2024-03-28T21:29:56Z
http://www.ijcto.org/index.php/IJCTO/oai
oai:ojs.ijcto.org:article/101
2014-05-14T17:01:16Z
IJCTO:CONF
On the evaluation of patient specific IMRT QA using EPID, dynalog files and patient anatomy
Defoor, Dewayne Lee; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Mavroidis, Panayiotis; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Quino, L Vazquez; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Gutierrez, Alonso; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Papanikolaou, Niko; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Stathakis, Sotiri; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Medical Physics
Purpose: This research, investigates the viability of using the Electronic portal imaging device (EPID) coupled with the treatment planning system (TPS), to calculate the doses delivered and verify agreement with the treatment plan. The results of QA analysis using the EPID, Delta4 and fluence calculations using the multi-leaf collimator (MLC) dynalog files on 10 IMRT patients are presented in this study.Methods: EPID Fluence Images in integrated mode and Dynalog files for each field were acquired for 10 IMRT (6MV) patients and processed through an in house MatLab program to create an opening density matrix (ODM) which was used as the input fluence for dose calculation with the TPS (Pinnacle3, Philips). The EPID used in this study was the aSi1000 Varian on a Novalis TX linac equipped with high definition MLC. The resulting dose distributions were then exported to VeriSoft (PTW) where a 3D gamma was calculated using 3 mm-3% criteria. The Scandidos Delta4 phantom was also used to measure a 2D dose distribution for all 10 patients and a 2D gamma was calculated for each patient using the Delta4 software.Results: The average 3D gamma for all 10 patients using the EPID images was 98.2% ± 2.6%. The average 3D gamma using the dynalog files was 94.6% ± 4.9%. The average 2D gamma from the Delta4 was 98.1% ± 2.5%. The minimum 3D gamma for the EPID and dynalog reconstructed dose distributions was found on the same patient which had a very large PTV, requiring the jaws to open to the maximum field size. Conclusion: Use of the EPID, combined with a TPS is a viable method for QA of IMRT plans. A larger ODM size can be implemented to accommodate larger field sizes. An adaptation of this process to Volumetric Arc Therapy (VMAT) is currently under way.-----------------------------Cite this article as: Defoor D, Mavroidis P, Quino L, Gutierrez A, Papanikolaou N, Stathakis S. On the evaluation of patient specific IMRT QA using EPID, dynalog files and patient anatomy. Int J Cancer Ther Oncol 2014; 2(2):020219. DOI: 10.14319/ijcto.0202.19
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Defoor
10.14319/ijcto.0202.19
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Defoor/ijcto.0102.19pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Defoor/ijcto.0202.19html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/117
2014-05-14T17:01:17Z
IJCTO:CONF
3D dictionary learning based iterative cone beam CT reconstruction
Bai, Ti; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Yan, Hao; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Shi, Feng; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Lou, Yifei; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Xu, Qiong; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Mou, Xuanqin; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Purpose: This work is to develop a 3D dictionary learning based cone beam CT (CBCT) reconstruction algorithm on graphic processing units (GPU) to improve the quality of sparse-view CBCT reconstruction with high efficiency. Methods: A 3D dictionary containing 256 small volumes (atoms) of 3 × 3 × 3 was trained from a large number of blocks extracted from a high quality volume image. On the basis, we utilized cholesky decomposition based orthogonal matching pursuit algorithm to find the sparse representation of each block. To accelerate the time-consuming sparse coding in the 3D case, we implemented the sparse coding in a parallel fashion by taking advantage of the tremendous computational power of GPU. Conjugate gradient least square algorithm was adopted to minimize the data fidelity term. Evaluations are performed based on a head-neck patient case. FDK reconstruction with full dataset of 364 projections is used as the reference. We compared the proposed 3D dictionary learning based method with tight frame (TF) by performing reconstructions on a subset data of 121 projections. Results: Compared to TF based CBCT reconstruction that shows good overall performance, our experiments indicated that 3D dictionary learning based CBCT reconstruction is able to recover finer structures, remove more streaking artifacts and also induce less blocky artifacts. Conclusion: 3D dictionary learning based CBCT reconstruction algorithm is able to sense the structural information while suppress the noise, and hence to achieve high quality reconstruction under the case of sparse view. The GPU realization of the whole algorithm offers a significant efficiency enhancement, making this algorithm more feasible for potential clinical application.-------------------------------Cite this article as: Bai T, Yan H, Shi F, Jia X, Lou Y, Xu Q, Jiang S, Mou X. 3D dictionary learning based iterative cone beam CT reconstruction. Int J Cancer Ther Oncol 2014; 2(2):020240. DOI: 10.14319/ijcto.0202.40
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Bai
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Bai/ijcto.0202.40pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Bai/ijcto.0202.40html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/287
2016-01-03T12:17:49Z
IJCTO:CONF
Development and biodistrubition modeling of 99mTc-DTPA
Bricha, Mohammed; Department of Radiopharmaceuticals Production, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
Hamzaoui, El-Mehdi; Department of IT Data Centre, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
Ben-Hamou, Kaddour; Department of Radiopharmaceuticals Production, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
Aboussaleh, Youssef; Department of Compartmental Neurosciences and Nutritional Health Team, Ibn Tofail University, Faculty of Sciences, Kenitra
Mesfioui, Abdelhalim; Department of Genitics - Neuroendocrinologiy and Biotechnology, Ibn Tofail University, Faculty of Sciences, Kenitra
Ettabia, Abdellah; Department of Radiopharmaceuticals Production, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
Moulahid, Hassan; Department of Radiopharmaceuticals Production, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
Zoubir, Brahim; Department of Radiopharmaceuticals Production, National Centre for Nuclear Energy, Sciences and Technologies, Rabat
El-Yahyaoui, Ahmed; Department of Radiochemistry and Nuclear Chemistry, Mohammed V University, Faculty of Sciences, Rabat
Nuclear Medicine
99m-Technitium; Biodistribution; Data Fitting; DTPA; Modeling; Urinary Excretion Kinetics; CNESTEN
Purpose: In this study, the team modeled the biodistribution and the efficiency of two 99m-technetium diethylene triamine penta acetate (99mTc-DTPA) based radiopharmaceuticals.Methods: The first radiopharmaceutical (DTPA-CNESTEN) is developed at the laboratories of the radiopharmaceutical production unit of the National Center for Nuclear Energy, Sciences and Technologies (CNESTEN-Morocco), and the second one is the commercial DTPA (DTPA-ref). Freeze-dried kits were successfully radiolabeled (radiochemical purity >95%) with the 99m Tc. Then drugs were injected to male BALB/c mice. In each 2 min, 5 min, 15 min, 1 h and 2 h time points after injections we evaluate tissue’s distributions characteristics. At the end, an automatic modeling of the data were recorded from thyroid, blood and urinary excretion kinetics and biodistribution in mice using both DTPA kits. The study aimed to extract the parameters of the function used to fit the recorded data. Results and Conclusion: the team concluded that the biodistribution of 99mTc-DTPA can be modeled using a combination of two exponential parts. Moreover, the resultant plots showed that there is strong correlation between the formula found in literature and the one derived on the basis of the fit of data sets in this study. In addition, it was found that the biodistribution behaviors of the developed kit and the commercial one were very close. The obtained results suggest that the developed DTPA has practically the same kinetics as the commercial one.
International Journal of Cancer Therapy and Oncology
2015-07-28
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.18
10.14319/ijcto.33.18
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.18/ijcto.33.18pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/19
2013-10-09T19:23:54Z
IJCTO:CONF
2nd Annual Conference of Bangladesh Medical Physics Society
(BMPS), Bangladesh Medical Physics Society; Ahsania Mission Cancer & General Hospital , Dhaka, Bangladesh & General Secretary
Bangladesh Medical Physics Society (BMPS).
Following abstracts proceedings are available in PDF:Challenges in brachytherapy dosimetryEssentials of periodic QA in radiation therapyInterventional radiotherapy or brachytherapy: new challenges for a successful techniqueExternal beam radiotherapy and high dose rate (HDR) brachytherapy treatment for carcinoma cervix practice in BPKMCH, Bharatpur, NepalTransition from 2D to 3D-CRT (NICRH experience)Conformal HDR brachytherapy for prostate cancer: comparison between boost and monotherapyImportance and procedures of quality control of diagnostic CT and CT simulator using for modern radiation therapyMedical physics and biomedical engineering education in Gono UniversityPlan verification in tomotherapy using 3D semiconductor detectorComparison of the miniaturized Co-60 and Ir-192 sources in HDR brachytherpy applicationsA Supine based cranio-spinal irradiation technique using moving field junctions radiotherapyStatistical variation and significance in the responses of thyroid follicular cells of two areas of Bangladesh due to radiotherapy into head and neck regionDetermining proper patient’s set-up parameters like IFD, gantry angles, and field width in Ca. breast to achieve precise treatment, in a center where TPS & simulators are not availableAccidental exposure of cancer patient and its preventionComparison of physical and enhanced dynamic wedges beam characteristics for 6 MV photon energy using pencil-beam convolution (PBC) algorithmProcedure to set up a radiotherapy unit & low cost unit analysisPatient setup verification and quality control (QC) of electronic portal imaging device (EPID)
International Journal of Cancer Therapy and Oncology
2013-09-15
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/BMPS
International Journal of Cancer Therapy and Oncology; Vol 1, No 1 (2013): September - October
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/BMPS/ijcto.0101.5pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/112
2014-05-14T17:01:17Z
IJCTO:CONF
GPU-Monte Carlo based fast IMRT plan optimization
Li, Yongbao; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Tian, Zhen; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Shi, Feng; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Purpose: Intensity-modulated radiation treatment (IMRT) plan optimization needs pre-calculated beamlet dose distribution. Pencil-beam or superposition/convolution type algorithms are typically used because of high computation speed. However, inaccurate beamlet dose distributions, particularly in cases with high levels of inhomogeneity, may mislead optimization, hindering the resulting plan quality. It is desire to use Monte Carlo (MC) methods for beamlet dose calculations. Yet, the long computational time from repeated dose calculations for a number of beamlets prevents this application. It is our objective to integrate a GPU-based MC dose engine in lung IMRT optimization using a novel two-steps workflow.Methods: A GPU-based MC code gDPM is used. Each particle is tagged with an index of a beamlet where the source particle is from. Deposit dose are stored separately for beamlets based on the index. Due to limited GPU memory size, a pyramid space is allocated for each beamlet, and dose outside the space is neglected. A two-steps optimization workflow is proposed for fast MC-based optimization. At first step, a rough dose calculation is conducted with only a few number of particle per beamlet. Plan optimization is followed to get an approximated fluence map. In the second step, more accurate beamlet doses are calculated, where sampled number of particles for a beamlet is proportional to the intensity determined previously. A second-round optimization is conducted, yielding the final result.Results: For a lung case with 5317 beamlets, 105 particles per beamlet in the first round, and 108 particles per beam in the second round are enough to get a good plan quality. The total simulation time is 96.4 sec.Conclusion: A fast GPU-based MC dose calculation method along with a novel two-step optimization workflow are developed. The high efficiency allows the use of MC for IMRT optimizations.--------------------------------Cite this article as: Li Y, Tian Z, Shi F, Jiang S, Jia X. GPU-Monte Carlo based fast IMRT plan optimization. Int J Cancer Ther Oncol 2014; 2(2):020244. DOI: 10.14319/ijcto.0202.44
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Li
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Li/ijcto.0202.44pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Li/ijcto.0202.44html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/281
2016-01-03T12:17:49Z
IJCTO:CONF
Volumic activities measurements and equivalent doses calculation of indoor 222Rn in Morocco
Choukri, Abdelmajid; Department of Physics, University of Ibn Tofail, Faculty of Sciences, Kenitra
Hakam, Oum Keltoum; Department of Physics, University of Ibn Tofail, Faculty of Sciences, Kenitra
Indoor Radon; Workplaces; Radioprotection; ionizing Radiations; Effective Dose; Natural Radioactivity
Purpose: As a way of prevention, we have measured the volumic activities of indoor 222Rn and we have calculated the corresponding effective dose in some dwellings and enclosed areas in Morocco. Seasonal variation of Radon activities and Relationships between variation of these activities and some parameters such height, depth and type of construction were also established in this work.Methods: The passive time-integrated method of using a solid state nuclear track detector (LR-115 type II) was employed. These films, cut in pieces of 3.4 ´ 2.5 cm2, were placed in detector holders and enclosed in heat-scaled polyethylene bags.Results: The measured volumic activities of radon vary in houses, between 31 and 136 Bq/m3 (0.55 and 2.39 mSv/year) with an average value of 80 Bq/m3 (1.41 mSv/year). In enclosed work area, they vary between 60 Bq/m3 (0.38 mSv/year) in an ordinary area to 1884 Bq/m3 (11.9 mSv/year) at not airy underground level of 12 m. the relatively higher volumic activities of 222Rn in houses were measured in Youssoufia and khouribga towns situated in regions rich in phosphate deposits. Measurements at the geophysical observatory of Berchid show that the volumic activity of radon increases with depth, this is most probably due to decreased ventilation. Conclusion: The obtained results show that the effective dose calculated for indoor dwellings are comparable to those obtained in other regions in the word. The risks related to the volumic activities of indoor radon could be avoided by simple precautions such the continuous ventilation. The reached high value of above 1884 Bq/m3 don't present any risk for workers health in the geophysical observatory of Berchid because workers spend only a few minutes by day in the cellar to control and reregister data.
International Journal of Cancer Therapy and Oncology
2015-03-29
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.1
10.14319/ijcto.33.1
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.1/ijcto.32.1pdf
http://www.ijcto.org/index.php/IJCTO/article/downloadSuppFile/ijcto.33.1/295
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/107
2014-05-14T17:01:16Z
IJCTO:CONF
Investigating the dosimetric effect of inter-fraction deformation in lung cancer stereotactic body radiotherapy (SBRT)
Jia, Jing
Tian, Zhen; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Gu, Xuejun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Yan, Hao; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Lung SBRT; Inter-Fraction Deformation; Dosimetric Effect; Adaptive Re-Planning
Purpose: We studied on the negative dosimetric effect of inter-fraction deformation in lung stereotactic body radiotherapy (SBRT), in order to see whether there is a need for adaptive re-planning of lung SBRT cases.Methods: Six lung cancer patients with different treatment fractions were retrospectively investigated. All the patients were immobilized and localized with a stereotactic body frame and were treated with cone-beam CT guidance for each fraction. We calculated the actual delivered dose of the treatment plan using the up-to-date patient geometry of each fraction, and compared the dose with the intended plan dose to investigate the dosimetric effect of the inter-fraction deformation. Due to the relatively poor image quality of CBCT, deformable registration was carried out between treatment planning CT and CBCT of each fraction to obtain deformed planning CT for more accurate dose calculation of delivered dose. The extent of the inter-fraction deformation was also evaluated by calculating the dice similarity coefficient between the contours on planning CT and those on deformed planning CT.Results: The average dice coefficients for PTV, spinal cord, esophagus were 0.87, 0.83 and 0.69, respectively. The volume of PTV covered by prescription dose was decreased by 23.78% on average for all fractions of all patients. For spinal cord and esophagus, the volumes covered by the constraint dose were increased by 4.57% and 3.83% in most fractions. The maximum dose was also increased by 4.11% for spinal cord and 4.29% for esophagus.Conclusion: Due to inter-fraction deformation, large deterioration was found in both PTV coverage and OAR sparing, which demonstrated the need for adaptive re-planning of lung SBRT cases to improve target coverage while reducing radiation dose to nearby normal tissues.----------------------------------------Cite this article as: Jia J, Tian Z, Gu X, Yan H, Jia X, Jiang S. Investigating the dosimetric effect of inter-fraction deformation in lung cancer stereotactic body radiotherapy (SBRT). Int J Cancer Ther Oncol 2014; 2(2):020225. DOI: 10.14319/ijcto.0202.25
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Jia
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Jia/ijcto.0202.25pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Jia/ijcto.0202.25html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/124
2014-05-14T17:01:18Z
IJCTO:CONF
An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems
Stanley, Dennis N; The University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Papanikolaou, Niko; The University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Gutierrez, Alonso N; The University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Medical Physics
Purpose: Quality assurance of the image quality for image guided localization systems is crucial to ensure accurate visualization and localization of target volumes. In this study, the stability of selected image parameters was assessed and evaluated for CBCT mode, planar radiographic kV mode and the radiographic MV EPID mode.Methods and Materials: The CATPHAN, QckV-1 and QC-3 phantoms were used to evaluate the image quality parameters. The planar radiographic images were analyzed in PIPSpro™ with spatial resolution (f30, f40, f50) being recorded. For OBI CBCT, High quality head Full-Fan acquisition and Pelvis Half-Fan acquisition modes were evaluated for Uniformity, Noise, Spatial Resolution, HU constancy and geometric distortion. Dose and kVp for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for planar kV and the CT detector for CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex Ion Chamber, webline electrometer and 1cm SolidWater™.Results: For each metric, values were normalized to the mean and the standard deviations were recorded. Table 1 shows the standard deviation for all results. Using this, tolerances can be reported as a warning threshold of 1σ and an action threshold of 2σ. Table 2 shows the warning and action tolerances for the planar radiographic modalities while Table 3 and 4 show tolerance levels for the Full-Fan and Half-Fan, respectively.Conclusion: A study was performed to assess the stability of the basic image quality parameters recommended by TG-142 for the Varian OBI and EPID Imaging systems. The two systems show consistent imaging and dosimetric properties over the evaluated time frame.----------------------------Cite this article as: Stanley DN, Papanikolaou N, Gutierrez AN. An evaluation of the stability of image quality parameters of Varian on-board imaging (OBI) and EPID imaging systems. Int J Cancer Ther Oncol 2014; 2(2):020236. DOI: 10.14319/ijcto.0202.36
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley/ijcto.0202.36pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley/ijcto.0202.36html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/103
2014-05-14T17:01:16Z
IJCTO:CONF
Upright CBCT: A novel imaging technique
Fave, Xenia J; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.
Yang, Jinzhong; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Balter, Peter A; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Court, Laurence E; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: We present a method for acquiring and correcting upright images using the on board CBCT imager. An upright imaging technique would allow for the introduction of upright radiation therapy treatments, which would benefit a variety of patients including those with thoracic cancers whose lung volumes are increased in an upright position and those who experience substantial discomfort during supine treatment positions.Methods: To acquire upright CBCT images, the linac head was positioned at 0 degrees, the KV imager and detector arms extended to their lateral positions, and the couch placed at 270 degrees. The KV imager was programmed to begin taking continuous fluoroscopic projections as the couch rotated from 270 to 90 degrees. The FOV was extended by performing this procedure twice, once with the detector shifted 14.5 cm towards the gantry and once with it shifted 14.5 cm away from the gantry. The two resulting sets of images were stitched together prior to reconstruction. The imaging parameters were chosen to deliver the some dose as that delivered during a simulation CT. A simulation CT was deformably registered to an upright CBCT reconstruction in order to evaluate the possibility of correcting the HU values via mapping.Results: Both spatial linearity and high contrast resolution were maintained in upright CBCT when compared to a simulation CT. Low contrast resolution and HU linearity decreased. Streaking artifacts were caused by the limited 180 degree arc angle and a sharp point artifact in the center of the axial slices resulted at the site of the stitching. A method for correcting the HUs was shown to be robust against these artifacts.Conclusion: Upright CBCT could be of great benefit to many patients. This study demonstrates its feasibility and presents solutions to some of its first hurdles before clinical implementation.--------------------------Cite this article as:Fave X, Yang J, Balter P, Court L. Upright CBCT: A novel imaging technique. Int J Cancer Ther Oncol 2014; 2(2):020221. DOI: 10.14319/ijcto.0202.21
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Fave
10.14319/ijcto.0202.21
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Fave/ijcto.0202.21pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Fave/ijcto.0202.21html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/118
2014-05-14T17:01:17Z
IJCTO:CONF
Measurement of exposure to personnel performing shielding evaluations
Page, Leland; Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Dodge, Cristina; Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Li, Guang; Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Wendt, Richard; Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: Determine the exposure to personnel accrued while performing shielding evaluations of diagnostic facilities.Methods: Shielding inspections were performed at three sites: a small animal imaging facility, an imaging center consisting of general x-ray, CT, and PET/CT rooms, and a cardiac catheterization lab. The small animal facility was evaluated using two 20 mCi Tc-99m uncollimated sources. The imaging center was evaluated using a 20 mCi source of F-18 for the PET/CT room and a collimated 25 mCi source of Tc-99m for the CT and x-ray rooms. The catheterization lab was evaluated using an uncollimated 35 mCi vial of Tc-99m. Electronic personal dosimeters (Rados RAD-60R, RADOS Technology Oy Turku, Finland) were worn by each of the personnel involved in performing shielding inspections. The cumulative exposure reading from the dosimeter for each surveyor was recorded.Results: The surveyor who positioned the open source at the small animal facility had an exposure reading of 3.5 mR in 5.5 hours. Those who were outside the room surveying the barriers had readings of 0 and 0.1 mR in 5 hours. For the cath lab, the surveyor positioning the source had a reading of 0.4 mR in 30 minutes, while those outside had readings of 0 mR. At the imaging center all personnel surveying the PET/CT room with an open F-18 source had readings of 2.0, 1.1, and 2.9 mR in 4 hours. Surveys of the CT and general radiography rooms with a collimated Tc-99m source had readings of 1.2, 0.9, and 0.2mR in 5 hours.Conclusion: The surveyors who were in the room with the sources had the highest exposures. Using a higher energy source (F-18) also led to higher exposures. By using a collimated source, the time to measure each barrier for penetrations was increased, but the surveyors’ exposures were lower.---------------------------------------Cite this article as: Page L, Dodge C, Li G, Wendt R. Measurement of exposure to personnel performing shielding evaluations. Int J Cancer Ther Oncol 2014; 2(2):020230. DOI: 10.14319/ijcto.0202.30
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Page
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Page/ijcto.0202.30pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Page/ijcto.0202.30html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/393
2016-01-03T12:17:49Z
IJCTO:CONF
Influence of Geant4 parameters on proton dose distribution
Merouani, Asad; Department of Physics, Faculty of Science, Mohammed V University, Rabat
El-Khayati, Naima; Department of Physics, Faculty of Science, Mohammed V University, Rabat
Amoros, Gabriel; Instituto de Física Corpuscular, Consejo Superior de Investigaciones Cientificas (CSIC/UV), Valencia
Proton Therapy; Monte Carlo Simulation; Geant4: Dose Distribution; Statistical Uncertainties
Purpose: The proton therapy presents a great precision during the radiation dose delivery. It is useful when the tumor is located in a sensitive area like brain or eyes. The Monte Carlo (MC) simulations are usually used in treatment planning system (TPS) to estimate the radiation dose. In this paper we are interested in estimating the proton dose statistical uncertainty generated by the MC simulations. Methods: Geant4 was used in the simulation of the eye’s treatment room for 62 MeV protons therapy, installed in the Istituto Nazionale Fisica Nucleare Laboratori Nazionali del Sud (LNS-INFN) facility in Catania. This code is a Monte Carlo based on software dedicated to simulate the passage of particles through the matter. In this work, we are interested in optimizing the Geant4 parameters on energy deposit distribution by proton to achieve the spatial resolution of dose distribution required for cancer therapy. We propose various simulations and compare the corresponding dose distribution inside water to evaluate the statistical uncertainties. Results: The simulated Bragg peak, based on facility model is in agreement with the experimental data, The calculations show that the mean statistical uncertainty is less than 1% for a simulation set with 5 × 104 events, 10-3 mm production threshold and a 10-2 mm step limit. Conclusion: The set of Geant4 cut and step limit values can be chosen in combination with the number of events to reach precision recommended from International Commission on Radiation Units and measurements (ICRU) in Monte Carlo codes for proton therapy treatment.
International Journal of Cancer Therapy and Oncology
2015-08-13
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.22
10.14319/ijcto.33.22
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.22/ijcto.33.22pdf
http://www.ijcto.org/index.php/IJCTO/article/downloadSuppFile/ijcto.33.22/419
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/39
2014-04-12T11:23:47Z
IJCTO:CONF
Water-light interaction: A novel pathway for multi hallmark therapy in cancer
Santana-Blank, Luis; Fundalas’ Cancer, Immunology and Neuroscience Programs, Venezuela.
Rodriguez-Santana, Elizabeth; Foundation for Interdisciplinary Research and Development Fundalas, Caracas 1020, Venezuela.
Reyes, Heberto; Clinica Avila, Radiology Department, Urbanizacion Altamira Caracas 1060, Venezuela.
J.M. Vargas Hospital, Radiology Department, Parroquia San Jose, Caracas 1010, Venezuela.
Santana-Rodriguez, Jesus; Foundation for Interdisciplinary Research and Development Fundalas, Caracas 1020, Venezuela.
Santana-Rodriguez, Karin; Foundation for Interdisciplinary Research and Development Fundalas, Caracas 1020, Venezuela.
Photobiomodulation
Laser photobiomodulation; Fourth phase of water; Cancer, Light-water interaction
Laser photobiomodulation (LPBM) has been proposed as a multi-target (multi-hallmark) therapy for cancer and other complex diseases based on an approach that aims to substitute and/or complement metabolic energy pathways through oxygen-dependent (e.g., cytochrome c oxidase (CcO)) and/or oxygen-independent (e.g., light-water interactions (e.g., F0-F1 motors)) mechanisms with critical signaling pathways in primarily aqueous media. Cellular and molecular bases for water-mediated, long-range, energy supplementation aimed at inducing and modulating physiologically reparative processes, including apoptosis, have been previously presented through a mechanism termed Photo Infrared Pulsed Biomodulation (PIPBM). Water’s role as an oscillator in LPBM has also been documented. These ideas were recently complemented by integrating the role of the quasi-crystalline exclusion zone (EZ) described by Pollack as the fourth phase of water. This is retrospective analysis of experimental and clinical data using an infrared pulsed laser device (IPLD). It found photo-induced effects over the water dynamics of burned rat tissue monitored by 1H-NMR transverse relaxation times (1/T2), indicating significantly greater structuring of water. In addition, a microdensitometry study of T2 weighted tumor heterogeneities from a phase I clinical trial of the IPLD in patients with advanced neoplasias and an algorithm for tumor characterization indicated significantly increased structuring of water, possibly proving a photobiomodulation effect over the EZ associated with histologically-confirmed selective photo-induced tumor cell death. To the best of our knowledge, this is the first clinical demonstration of light-induced effects over the EZ. It supports our premise that LPBM can increase potential energy in the EZ, which then acts as a rechargeable electrolytic bio-battery for the external selective supplementation of the energy demand required for cellular work, signaling pathways and gene expression in the presence of injury-induced redox potentials. It further suggests that EZ structuring may be used as a predicator of anticancer response before measurable tumor volume reduction.------------------------------------------------Cite this article as: Santana-Blank L, Rodriguez-Santana E, Reyes H, Santana- Rodriguez J, Santana- Rodriguez K. Water-light interaction: A novel pathway for multi hallmark therapy in cancer. Int J Cancer Ther Oncol 2014; 2(1):02012.DOI: http://dx.doi.org/10.14319/ijcto.0201.2
International Journal of Cancer Therapy and Oncology
2013-12-21
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Santana-Blank1
10.14319/ijcto.0201.2
International Journal of Cancer Therapy and Oncology; Vol 2, No 1 (2014): January - March
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Santana-Blank1/ijcto.0201.2pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Santana-Blank1/ijcto.0201.2html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/113
2014-05-14T17:01:17Z
IJCTO:CONF
Non-invasive pre-clinical MR imaging of prostate tumor hypoxia for radiation therapy prognosis
White, Derek; UT Arlington Biomedical Engineering, Texas, USA.
Mason, Ralph P; UT Southwestern Prognostic Radiology Lab, Texas, USA.
Medical Physics
Purpose: To investigate the usefulness of Oxygen-Enhanced Magnetic Resonance Imaging (OE-MRI) changes in signal intensity related to oxygen challenge for predicting tumor response to radiation therapy.Methods: Dynamic MR signal changes were acquired using Varian 4.7T small animal MR scanner prior to image-guided radiation therapy (IGRT) of small (n = 6) and large subcutaneous (n = 5) prostate tumors in adult male rats. An interleaved blood-oxygen level dependent (BOLD) and tissue-oxygen level dependent (TOLD) data acquisition or (IBT) was performed using a baseline of medical air as positive control and using medical oxygen as a breathing challenge. BOLD used a 2-D multi-slice spoiled gradient-echo with multi-echo sequence. TOLD used a 2-D multi-slice spoiled gradient-echo sequence. Voxel changes in signal intensity were determined by a correlation coefficient mapping technique. Irradiation technique planned consisted of 1F × 15 Gy AP/PA or 2F × 7.5 Gy AP/PA to the gross tumor volume (GTV). Tumor growth measurements were recorded over time to assess the response to IGRT.Results: BOLD and TOLD signals variously illustrated positive or negative impulse responses in the tumor ROI due to inhaling medical oxygen. Correlation coefficient mapping demonstrated heterogeneity in tumors after inhaling medical oxygen. BOLD and TOLD signals exhibited increased changes in signal intensities after the first fraction of dose. Multi-fractionation had minimum effect until the second fraction of dose was applied. Tumor growth delays were observed when inhaling medical oxygen during IGRT.Conclusion: OE-MRI is a non-invasive imaging modality that can provide insight to the oxygen status of tumors. Observed increase percent changes in BOLD and TOLD signal intensities after the first fraction of dose suggest tumors experienced reoxygenation. OE-MRI could be used for predicting tumor response to IGRT when using medical oxygen for increasing GTV radiosensitivity, suggesting patient stratification for clinical implementation.------------------------------Cite this article as: White DA, Mason RP. Non-invasive pre-clinical MR imaging of prostate tumor hypoxia for radiation therapy prognosis. Int J Cancer Ther Oncol 2014; 2(2):020243. DOI: 10.14319/ijcto.0202.43
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/White
10.14319/ijcto.0202.43
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/White/ijcto.0202.43pdf
http://www.ijcto.org/index.php/IJCTO/article/view/White/ijcto.0202.43html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/282
2016-01-03T12:17:49Z
IJCTO:CONF
Uranium and radium activities measurements and calculation of effective doses in some drinking water samples in Morocco
Hakam, Oum Keltoum; Department of Physics, University of Ibn Tofail, Faculty of Sciences, Kenitra
Choukri, Abdelmajid; Department of Physics, University of Ibn Tofail, Faculty of Sciences, Kenitra
Abbad, Aicha; Department of Geography, University of Ibn Tofail, Faculty of Human Sciences and Letters, Kenitra
Elharfi, Ahmed; Department of Chemistry, University of Ibn Tofail, Faculty of Sciences, Kenitra
Uranium; Radium; Public Health; Radioprotection; Effective Doses
Purpose: As a way of prevention, we have measured the activities of uranium and radium isotopes (234U, 238U, 226Ra, 228Ra) for 30 drinking water samples collected from 11 wells, 9 springs (6 hot and 3 cold), 3 commercialised mineral water, and 7 tap water samples. Methods: Activities of the Ra isotopes were measured by ultra-gamma spectrometry using a low background and high efficiency well type germanium detector. The U isotopes were counted in an alpha spectrometer.Results: The measured Uranium and radium activities are similar to those published for other non-polluting regions of the world. Except in one commercialised gaseous water sample, and in two hot spring water samples, the calculated effective doses during one year are inferior to the reference level of 0.1 mSv/year recommended by the International Commission on Radiological Protection. Conclusion: These activities don't present any risk for public health in Morocco. The sparkling water of Oulmes is occasionally consumed as table water and waters of warm springs are not used as main sources of drinking water.
International Journal of Cancer Therapy and Oncology
2015-03-29
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.2
10.14319/ijcto.33.2
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.2/ijcto.33.2pdf
http://www.ijcto.org/index.php/IJCTO/article/downloadSuppFile/ijcto.33.2/296
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/108
2014-05-14T17:01:17Z
IJCTO:CONF
Doppler string phantom for assessment of clinical doppler ultrasound velocity measurement
Zhang, Yi; Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
Lynch, Ted; Computerized Imaging Reference Systems, Inc, Norfolk, Virginia, USA.
Hangiandreou, Nicholas J; Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
Medical Physics
Purpose: The Doppler string phantom provides accurate velocity of the string motion; it can be used to calibrate Doppler ultrasound (US) velocity measurements and to evaluate variations due to intrinsic spectral broadening. We developed a semi‐automated method to estimate the mode velocity (Vmode) and peak velocity (Vmax) based on duplex US images from a string phantom, and use them to assess clinical Doppler US velocity measurement.Methods: Steady motion of a rubber O‐ring (20 – 110 cm/s) in a CIRS Doppler String phantom (Model 043) was studied using GE LOGIQ E9 system with a 9L probe. 5 s of Doppler spectral data was averaged to generate a mean spectral profile. It was fitted by a Gaussian function and Vmode was defined as the velocity of the Gaussian peak, while Vmax is defined as the velocity at which the spectral profile falls to within 1 SD of the background. Vmode and Vmax were evaluated against the prescribed motor velocity. Repeatability and variation to scanning parameters were analyzed and reported in % range, i.e. (max – min) / mean.Results: Vmode and Vmax had good repeatability over six days (6.0% for Vmode, 2.9% for Vmax). Gain, compression, scale, sample volume (SV) depth and length, frequency and beam steering all had minimal impact on Vmode and Vmax (variations ≤ 4.4%). Doppler angle θ had minimal effect on Vmode (2.2%) but a strong effect on Vmax (26% increase as θ increased from 10° to 60°). Vmode was linearly correlated with but overestimated the motor velocity (Pearson’s r = 1.05, R2 = 1).Conclusion: This study developed a simple yet robust Vmode and Vmax estimation method. Combined with a string phantom, these velocity estimators are shown to be a useful tool to evaluate clinical Doppler US system performance. For the tested system, only Doppler angle has an appreciable impact on Vmax estimation.--------------------------------------------Cite this article as: Zhang Y, Lynch T, Hangiandreou NJ. Doppler string phantom for assessment of clinical doppler ultrasound velocity measurement. Int J Cancer Ther Oncol 2014; 2(2):020246. DOI:10.14319/ijcto.0202.46
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Zhang
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Zhang/ijcto.0202.46pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Zhang/ijcto.0202.46html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/125
2014-05-14T17:01:18Z
IJCTO:CONF
Investigating magnetic field dose effects in small animals: a Monte Carlo study
Rubinstein, Ashley Erin; Departments of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Guindani, Michele; Departments of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Hazle, John D; Departments of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Court, Laurence E; Departments of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: In MRI-linac treatments, radiation dose distributions are affected by magnetic fields, especially at high-density/low-density interfaces. Radiobiological consequences of magnetic field dose effects are presently unknown and preclinical studies are desirable. This study investigates the optimal combination of beam energy and magnetic field strength needed for preclinical murine studies.Methods: The Monte Carlo code MCNP6 was used to simulate the effects of a magnetic field when irradiating a mouse lung phantom with a 1.0 cm × 1.0 cm photon beam. Magnetic field dose effects were examined using various beam energies (225 kVp, 662 keV [Cs-137], and 1.25MeV [Co-60]) and magnetic field strengths (0.75 T, 1.5 T, and 3 T). The resulting dose distributions were compared to Monte Carlo results for humans with various field sizes and patient geometries using a 6MV/1.5T MRI-linac.Results: In human simulations, the addition of a 1.5 T magnetic field causes an average dose increase of 49% (range: 36% - 60%) to lung at the soft tissue-lung interface and an average dose decrease of 30% (range: 25% - 36%) at the lung-soft tissue interface. In mouse simulations, no magnetic field dose effects were seen with the 225 kVp beam. The dose increase for the Cs-137 beam was 12%, 33%, and 49% for 0.75 T, 1.5 T, and 3.0 T magnetic fields, respectively while the dose decrease was 7%, 23%, and 33%. For the Co-60 beam the dose increase was 14%, 45%, and 41%, and the dose decrease was 18%, 35%, and 35%.Conclusion: The magnetic field dose effects observed in mouse phantoms using a Co-60 beam with 1.5 T or 3 T fields or a Cs-137 beam with a 3T field fall within the range seen in humans treated with an MRI-linac. These irradiator/magnet combinations are therefore suitable for preclinical studies investigating potential biological effects of delivering radiation therapy in the presence of a magnetic field.---------------------------Cite this article as: Rubinstein A, Guindani M, Hazle JD, Court LE. Investigating magnetic field dose effects in small animals: a Monte Carlo study. Int J Cancer Ther Oncol 2014; 2(2):020233. DOI: 10.14319/ijcto.0202.33
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Rubinstein
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Rubinstein/ijcto.0202.33pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Rubinstein/ijcto.0202.33html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/104
2014-05-14T17:01:16Z
IJCTO:CONF
A real-time virtual delivery system for photon radiotherapy delivery monitoring
Shi, Feng; Division of Medical Physics and Engineering, Department of Radiation Oncology University of Texas Southwestern Medical Center, Dallas, TX, USA.
Gu, Xuejun; Division of Medical Physics and Engineering, Department of Radiation Oncology University of Texas Southwestern Medical Center, Dallas, TX, USA.
Graves, Yan Jiang; Division of Medical Physics and Engineering, Department of Radiation Oncology University of Texas Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Division of Medical Physics and Engineering, Department of Radiation Oncology University of Texas Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Division of Medical Physics and Engineering, Department of Radiation Oncology University of Texas Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Purpose: Treatment delivery monitoring is important for radiotherapy, which enables catching dosimetric error at the earliest possible opportunity. This project develops a virtual delivery system to monitor the dose delivery process of photon radiotherapy in real-time using GPU-based Monte Carlo (MC) method.Methods: The simulation process consists of 3 parallel CPU threads. A thread T1 is responsible for communication with a linac, which acquires a set of linac status parameters, e.g. gantry angles, MLC configurations, and beam MUs every 20 ms. Since linac vendors currently do not offer interface to acquire data in real time, we mimic this process by fetching information from a linac dynalog file at the set frequency. Instantaneous beam fluence map (FM) is calculated based. A FM buffer is also created in T1 and the instantaneous FM is accumulated to it. This process continues, until a ready signal is received from thread T2 on which an in-house developed MC dose engine executes on GPU. At that moment, the accumulated FM is transferred to T2 for dose calculations, and the FM buffer in T1 is cleared. Once the dose calculation finishes, the resulting 3D dose distribution is directed to thread T3, which displays it in three orthogonal planes in color wash overlaid on the CT image. This process continues to monitor the 3D dose distribution in real-time.Results: An IMRT and a VMAT cases used in our patient-specific QA are studied. Maximum dose differences between our system and treatment planning system are 0.98% and 1.58% for the IMRT and VMAT cases, respectively. The update frequency is >10Hz and the relative uncertainty level is 2%.Conclusion: By embedding a GPU-based MC code in a novel data/work flow, it is possible to achieve real-time MC dose calculations to monitor delivery process.------------------------------Cite this article as: Shi F, Gu X, Graves YJ, Jiang S, Jia X. A real-time virtual delivery system for photon radiotherapy delivery monitoring. Int J Cancer Ther Oncol 2014; 2(2):020222. DOI: 10.14319/ijcto.0202.22
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Shi
10.14319/ijcto.0202.22
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Shi/ijcto.0202.22pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Shi/ijcto.0202.22html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/119
2014-05-14T17:01:18Z
IJCTO:CONF
Skeletal muscle lipid quantification in lean and diabetic subjects using in vivo proton MR spectroscopy
Valaparla, Sunil K; Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Boone, Goldie; Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Ripley, Erika M; Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Giuseppe, Daniele; Diabetes Division, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Duong, Timothy Q; Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Abdul-Ghani, Muhammad; Diabetes Division, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Clarke, Geoffrey D; Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, USA.
Medical Physics
Purpose: To quantify and compare the intramyocellular (IMCL), extramyocellular (EMCL) lipids and total fat fraction in human vastus lateralis muscle between lean and type 2 diabetic (T2DM) subjects using long echo time (TE) STEAM proton MR spectroscopy (1H-MRS). Methods: 1H-MRS using single voxel (15 × 15 × 15 mm3) stimulated acquisition mode (STEAM) was performed in right vastus lateralis m. on 10 lean controls (age: 28.3 ± 3.94 yo, BMI: 24.25 ± 3.20 kg/m2) and 7 type 2 diabetic (age: 54.28 ± 6.42 yo, BMI: 31.34 ± 3.13 kg/m2) subjects with Siemens 3T MRI and a four-channel flex coil. Unsuppressed water spectra (NSA = 16) with TR/TE = 3000/30 ms, TM = 10 ms BW = 2000 Hz, and water-suppressed spectra (NSA = 128) with TR/TE = 3000/270 ms, TM = 10 ms, fixed water suppression BW = 50 Hz were acquired. Spectral intensity ratios of IMCL-CH2, EMCL-CH2 and total lipid (IMCL + EMCL) with unsuppressed water signal (W) were converted into absolute concentrations expressed in mmol/kg. Fat fraction (100 × F/(W+F)) was also calculated, where F includes the signal intensities of IMCL and EMCL methylene (CH2)n, peaks only.Results: Comparison of IMCL (controls: 11.70 ± 6.7, T2DM: 21.74 ± 10.2, p < 0.01), EMCL (controls: 22.89 ± 18.42, T2DM: 77.21 ± 33.4, p < 0.001) and total lipid (64.35 mmol/kg less in controls, p < 0.001) showed statistical significance using two-tailed student’s t-test. Mean fat fraction (%) exhibited considerable inter-individual variability for controls (3.14 ± 2.09; range: 1.34 – 7.04) and T2DM (9.34 ± 2.88; range: 4.15 – 13.67) and deemed significant (p < 0.05). Conclusion: Single voxel STEAM 1H-MRS at long TE provides a robust non-invasive method for characterizing lipids within localized muscle regions, with well-resolved IMCL/EMCL peak separation. Regional lipid estimate and fat fraction in vastus lateralis muscle is significantly different in T2DM compared to normal lean controls.------------------------------Cite this article as: Valaparla SK, Boone GRE, Ripley EM, Giuseppe D, Duong TQ, Abdul-Ghani M, Clarke GD. Skeletal muscle lipid quantification in lean and diabetic subjects using in vivo proton MR spectroscopy. Int J Cancer Ther Oncol 2014; 2(2):020239. DOI: 10.14319/ijcto.0202.39
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Valaparla
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Valaparla/ijcto.0202.39pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Valaparla/ijcto.0202.39html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/395
2016-01-03T12:17:49Z
IJCTO:CONF
The effect of the presence of the patient on the particles dose estimations in high energy linear accelerator mazes
Ghassoun, Jillali; Department of Physics, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech
Medical Physics
Radiotherapy; Accelerator; Neutron; Gamma; Phantom; Dose; MCNP; Maze
Purpose: Medical accelerators operating above 10 MV are a source of undesirable neutron radiations which contaminate the therapeutic photon beam. These photo-neutrons which contaminate the therapeutic beam can also generate secondary gamma rays, via inelastic and capture reactions, which increase the undesirable dose to the patient body, the oncology staff and the general public. The purpose of the present work is to investigate, through Monte Carlo simulation, the effect of the presence of the patient on the neutron and gamma rays dose calculations. Methods: To illustrate this effect, the MCNP5 code was used to model a radiotherapy room of a medical linear accelerator operating at 18 MV and to calculate the neutron and the secondary gamma ray energy spectra and the dose equivalent, at various points along the centerline of the maze, in the absence and presence of the patient. Results and Conclusion: The obtained results show a significant change in the neutron energy spectra in the presence of the patient especially in the thermal neutron energy region. The results also indicate that the presence of a patient does not affect the simulated neutron and gamma rays dose equivalents at the maze entrance for mazes greater than 3 m long. A significant change in dose equivalent calculated values was observed when the length of the maze is less than 3 m.
International Journal of Cancer Therapy and Oncology
2015-09-01
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.21
10.14319/ijcto.33.21
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.21/ijcto.33.21pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/98
2014-05-14T17:01:16Z
IJCTO:CONF
Daily fraction dose recalculation based on rigid registration using Cone Beam CT
Bosse, Courtney; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Tuohy, Rachel; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Mavroidis, Panayiotis; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Shi, Zheng; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Crownover, Richard; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Gutierrez, Alonso; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Papanikolaou, Niko; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Stathakis, Sotiri; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Medical Physics
Purpose: To calculate the daily fraction dose for CBCT recalculations based on rigid registration and compare it to the planned CT doses.Methods: For this study, 30 patients that were previously treated (10 SBRT lung, 10 prostate and 10 abdomen) were considered. The daily CBCT images were imported into the Pinnacle treatment planning system from Mosaic. Pinnacle was used to re-contour the regions of interest (ROI) for the specific CBCT by copying the contours from the original CT plan, planned by the prescribing physician, onto each daily CBCT and then manually reshaping contours to match the ROIs. A new plan is then created with the re-contoured CBCT as primary image in order to calculate the daily dose delivered to each ROI. The DVH values are then exported into Excel and overlaid onto the original CT DVH to produce a graph.Results: For the SBRT lung patients, we found that there were small daily volume changes in the lungs, trachea and esophagus. For almost all regions of interest we found that the dose received each day was less than the predicted dose of the planned CT while the PTV dose was relatively the same each day. The results for the prostate patients were similar, showing slight differences in the DVH values for different days in the rectum and bladder but similar PTV.Conclusion: By comparing daily fraction dose between the re-contoured CBCT images and the original planned CT show that PTV coverage for both prostate and SBRT, it has been shown that for PTV coverage, a planned CT is adequate. However, there are differences between the dose for the organs surrounding the PTV. The dose difference is less than the planned in most instances.-----------------------Cite this article as: Bosse C, Tuohy R, Mavroidis P, Shi Z, Crownover R, Gutierrez A, Papanikolaou N, Stathakis S. Daily fraction dose recalculation based on rigid registration using Cone Beam CT. Int J Cancer Ther Oncol 2014; 2(2):020217. DOI: 10.14319/ijcto.0202.17
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Bosse
10.14319/ijcto.0202.17
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Bosse/ijcto.0202.17pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Bosse/ijcto.0202.17html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/114
2014-05-14T17:01:17Z
IJCTO:CONF
Characterization of tumor dose heterogeneity for 90Y microsphere therapies using voxel- based dosimetry
Mikell, Justin; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Mourtada, Firas; Christiana Care, Newark, DE, USA.
Mahvash, Armeen; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Kappadath, S Cheenu; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: Dosimetry for 90Y microsphere therapies (YMT) with Standard (SM) and Partition (PM) models provide only uniform dose estimates to tumor and liver. Our objective is to calculate tumor dose heterogeneity, known to effect response, using voxel-based dosimetry and investigate the limitations of SM and PM.Methods: Voxel-based dosimetry was performed on 17 YMT patients using Monte Carlo DOSXYZnrc. 90Y activity and tissue/density distributions were based on quantitative 90Y bremsstrahlung SPECT/CT. Tumors (n=31), liver, and treatment lobe/segments were segmented on diagnostic CT or MR. Dose volume histograms (DVH) were created for tumors and normal liver. Bland-Altman analysis compared voxel-based mean absorbed doses to tumor and liver with SM and PM. Tumor and normal liver absorbed dose heterogeneity were investigated through metrics: integral uniformity (IU), D10/D90, COV. Correlations of heterogeneity with voxel-based mean doses and volumes were evaluated.Results: Heterogeneity metrics (mean ± 1σ) for tumor dose were COV = 0.48 ± 0.28, D10/D90 = 4.7 ± 3.9, and IU = 0.8 ± 0.18. Heterogeneity metrics correlated with tumor volume (r > 0.58) but not tumor mean doses (r < 0.20). Voxel-based tumor mean doses correlated with PM (r = 0.84) but not SM (r = 0.08). Both yielded poor limits of agreement with of 83 ± 174 and -28 ± 181 Gy, respectively. Normal liver heterogeneity metrics (mean ± 1σ) were COV = 0.83 ± 0.29, D10/D90 = 12 ± 15, and IU = 0.97 ± 0.03. Only D10/D90 (r = 0.49) correlated with mean normal liver absorbed dose. Voxel-based normal liver/lobe mean doses correlated with PM (r = 0.96), but had poor limits of agreement (26 ± 29 Gy).Conclusion: Tumor doses have high levels of heterogeneity that increase with volume but are independent of dose. Voxel-based DVH and dose heterogeneity metrics will promote accurate characterization of tumor response following YMT.--------------------------------------Cite this article as: Mikell J, Mourtada F, Mahvash A, Kappadath SC. Characterization of tumor dose heterogeneity for 90Y microsphere therapies using voxel- based dosimetry. Int J Cancer Ther Oncol 2014; 2(2):020228. DOI: 10.14319/ijcto.0202.28
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Mikell
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Mikell/ijcto.0202.28pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Mikell/ijcto.0202.28html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/283
2016-01-03T12:17:49Z
IJCTO:CONF
Dosimetry estimation of SPECT/CT for iodine 123-labeled metaiodobenzylguanidine in children
Mhiri, Aida; Department of Nuclear Medicine, Salah Azaiez Institute, Tunis
Slim, Ihsen; Department of Nuclear Medicine, Salah Azaiez Institute, Tunis
Slimène, Mohamed; Department of Nuclear Medicine, Salah Azaiez Institute, Tunis
Radiation oncology
123II-Metaiodobenzylguanidine; SPECT-CT- Pediatric; Dosimetry
Purpose: To evaluate the additional radiation exposure in terms of effective dose incurred by patients in the CT (computed tomography) portion of 123I-MIBG (123II-metaiodobenzylguanidine) study with SPECT/CT (Single photon emission computed tomography associated to computed tomography) in some pediatric patients of our department. Methods: Data from 123II-MIBG scans comprising 50 children were presented in this study. The contribution of total effective dose imparted by the nuclear tracer and patient's age was calculated. Effective dose from the CT portion of the examination is also estimated.SPECT acquisitions were performed with a dual-headed SPECT unit with an integrated 2-slice CT scanner (Symbia T E-Cam, Siemens Medical Systems, Erlangen, Germany). The CT acquisition were performed using a tube current modulation system (Care Dose 4D). Parameters used were: tube current of 30 - 60 mAs, slice thickness of 3-5 mm, and tube voltage of 110 kV. Results: Our results show that SPECT dosimetry depends on administered activity and patient’s age and weight. For CT scan, effective dose is affected by tube current (mA), tube potential (kVp), rotation speed, pitch, slice thickness, patient mass, and the exact volume of the patient that is being imaged. Conclusion: For children, 123II-MIBG study with SPECT/CT should be performed using the lowest available voltage and current. A sensible choice of these two parameters used can significantly reduce radiation dose, without any compromise in the quality of the diagnostic information.
International Journal of Cancer Therapy and Oncology
2015-03-29
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.3
10.14319/ijcto.33.3
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.3/ijcto.33.3pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/109
2014-05-14T17:01:17Z
IJCTO:CONF
Mathematical analysis of approximate biological effective dose (BED) calculation for multi-phase radiotherapy treatment plans
Kauweloa, Kevin I; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Gutierrez, Alonso N; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Bergamo, Angelo; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Stathakis, Sotirios; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Papanikolaou, Niko; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Mavroidis, Panayiotis; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Medical Physics
Purpose: There is growing interest about biological effective dose (BED) and its application in treatment plan evaluation due to its stronger correlation with treatment outcome. An approximate biological effective dose (BEDA) equation was introduced in order to simplify BED calculations by treatment planning systems in multi-phase treatments. The purpose of this work is to reveal its mathematical properties relative to the true, multi-phase BED (BEDT) equation.Methods: The BEDT equation was derived and used to reveal the mathematical properties of BEDA. MATLAB (MathWorks, Natick, MA) was used to simulate and analyze common and extreme clinical multi-phase cases. In those cases, percent error and Bland-Altman analysis were used to study the significance of the inaccuracies of BEDA for different combinations of total doses, numbers of fractions, doses per fractions and α/β values. All the calculations were performed on a voxel-basis in order to study how dose distributions would affect the accuracy of BEDA.Results: When the voxel dose-per-fractions (DPF) delivered by both phases are equal, BEDA and BEDT are equal (0% error). In heterogeneous dose distributions, which significantly vary between the phases, there are fewer occurrences of equal DPFs and hence the imprecision of BEDA is greater. It was shown that as the α/β ratio increased the accuracy of BEDA would improve. Examining twenty-four cases, it was shown that the range of DPF ratios for 3% Perror varied from 0.32 to 7.50Gy, whereas for Perror of 1% the range varied from 0.50 to 2.96Gy.Conclusion: The DPF between the different phases should be equal in order to render BEDA accurate. OARs typically receive heterogeneous dose distributions hence the probability of equal DPFs is low. Consequently, the BEDA equation should only be used for targets or OARs that receive uniform or very similar dose distributions by the different treatment phases.---------------------------Cite this article as: Kauweloa KI, Gutierrez AN, Bergamo A, Stathakis S, Papaniko-laou N, Mavroidis P. Mathematical analysis of approximate biological effective dose (BED) calculation for multi-phase radiotherapy treatment plans. Int J Cancer Ther Oncol 2014; 2(2):020226. DOI: 10.14319/ijcto.0202.26
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Kauweloa
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Kauweloa/ijcto.0202.26pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Kauweloa/ijcto.0202.26html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/126
2014-05-14T17:01:18Z
IJCTO:CONF
SPECT deadtime count loss correction using monitor source method
Siman, Wendy; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Kappadath, Cheenu S; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: Deadtime-count-loss (DTloss) correction using monitor source (MS) requires: 1) uniform fractional DTloss across FOV, 2) high statistics MS images both with & without the object. The aims are validating condition 1 and developing a practical protocol that satisfies conditions 2 with minimal additional study duration.Methods and Materials: SPECT images of non-uniform phantoms (4GBq 99mTc) along with MS (20MBq 99mTc) attached to each detector were acquired multiple times over 48 hours in photopeak and scatter energy window (EW) using Siemens-SymbiaS and GE-D670. Planar images of the MS alone were acquired. Photopeak counts for the MS ROIs were > 100kcts. Fractional DTloss uniformity across the FOV was evaluated by correlating count rates in different ROIs on projection images at different DTloss levels. The correction factor for each SPECT projection at every time point was calculated as the ratio of time-corrected MS count rates with & without the phantom.The DTloss-corrected projections for each SPECT acquisition were decay corrected to one time point. The correction accuracy was assessed against DTloss estimated by paralyzable model. The accuracy of projection-based DTloss correction for SPECT was evaluated. A method to model projection DTloss based on a subset of measured projection DTloss was investigated. The relation of DTloss between photopeak and scatter EW was explored.Results: The fractional DTloss was uniform across the FOV (r > 0.99), validating condition 1. The MS method was accurate to > 99% for planar and SPECT. Measured DTloss from 3-to-5 projections/detector may be used to estimate DTloss with accuracy > 98% for all SPECT projections by modeling DTloss with measured projection rate. The correction factor in photopeak and scatter EW are equivalent with > 99% agreement.Conclusion: MS method can accurately correct planar and SPECT DTloss. Sparse sampling of the projection DTloss allows acquiring MS counts with high statistics with minimal additional study duration making it clinically practical.--------------------------------------Cite this article as: Siman W, Kappadath SC. SPECT deadtime count loss correction using monitor source method. Int J Cancer Ther Oncol 2014; 2(2):020234. DOI: 10.14319/ijcto.0202.34
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Siman
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Siman/ijcto.0202.34pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Siman/ijcto.0202.34html
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oai:ojs.ijcto.org:article/102
2014-05-14T17:01:16Z
IJCTO:CONF
Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios
Dodge, Cristina T; Department of Imaging Physics, M.D. Anderson Cancer Center, Houston, Texas, USA.
Gress, Dustin; Department of Imaging Physics, M.D. Anderson Cancer Center, Houston, Texas, USA.
Medical Physics
Purpose: To validate the use of the 16 cm CTDI phantom to estimate the 32 cm phantom CTDIw with tabulated data from previous years.Methods: A retrospective analysis of CTDI measurements was performed from the annual physics testing reports of four Siemens Symbia (Emotion) T6, one Siemens Symbia (Emotion) T16, one Siemens Sensation Open, one Siemens Sensation 16, one Siemens Sensation 32, two GE LightSpeed 16 and five GE VCT CT scanners. For each annual report, the ratio of the 16 cm: 32 cm CTDI phantom measurements was calculated from mAs-normalized CTDI100. The ratios from a) the acceptance test, b) one year after the acceptance test or c) an average ratio of all of the previous years (range 4-8 years), were then used to estimate 32 cm CTDI phantom measurements based on active 16 cm CTDI measurements. The average percent difference between measured and calculated CTDIw was determined per scanner for all years.Results: The most accurate results were obtained when using the average ratios of all the previous years, -2% to 3% difference across all scanner models. For the ratios of the year after the acceptance test, the difference ranged from -3% to 7%, while the data estimated from the acceptance testing results yielded the largest percent difference -4% to 8%. The 64-detector row system estimates displayed the greatest variation, followed by the 16-detector row scanners, while the 6-detector row system estimates were the most accurate.Conclusion: Compared to the Siemens and GE specified CTDI limits of ± 15-30% , the variation in the estimated 32 cm phantom CTDIw values was 2-15 times lower, dependent on the scanner model and method of estimation. The variation was considerably less (2-3%) with ratios of all the previous years, perhaps indicative of year to year variations that can result in greater error.------------------------------Cite this article as: Dodge C, Gress D. Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios. Int J Cancer Ther Oncol 2014; 2(2):020220. DOI: 10.14319/ijcto.0202.20
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Dodge
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Dodge/ijcto.0202.20pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Dodge/ijcto.0202.20html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/120
2014-05-14T17:01:18Z
IJCTO:CONF
2D vs 3D gamma analysis: Establishment of comparable clinical action limits
Pulliam, Kiley B; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.
Huang, Jessie Y; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.
Bosca, Ryan; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.
Followill, David; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Kry, Stephen F; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance; these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, because of the different search space available. We compared the results of 2D and 3D gamma analysis (where both datasets were generated the same way) for clinical treatment plans. Methods: 50 IMRT plans were selected from our database and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated”) and Monte Carlo-recalculated (“reference”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma and percentage of pixels passing gamma.Results: Average gamma and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. Average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a differences ranging from 0.8% to 1.5%. No appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs. 3D) were observed.Conclusion: We found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. Factors such as inherent dosimeter differences may be an important additional consideration to the extra dimension of available data that was evaluated in this study.------------------------------------Cite this article as: Pulliam KB, Huang JY, Bosca R, Followill D, Kry SF. 2D vs. 3D gamma analysis: Establishment of comparable clinical action limits. Int J Cancer Ther Oncol 2014; 2(2):020231. DOI: 10.14319/ijcto.0202.31
International Journal of Cancer Therapy and Oncology
2014-04-09
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info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Pulliam
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Pulliam/ijcto.0202.31pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Pulliam/ijcto.0202.31html
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oai:ojs.ijcto.org:article/397
2016-01-03T12:17:49Z
IJCTO:CONF
Study the effects of radon inhalation on biomechanical properties of blood in rats
Fawzy Eissa, Mostafa; Department of Physics, Faculty of Science, Beni-Suef University, Beni-Suef
Ahmed, Ashour; Department of Physics, Faculty of Science, Beni-Suef University, Beni-Suef
Abdel-Salam, Omar; National Research Centre, Dokki, Cairo
Shahin, Fayez; Department of Physics, Faculty of Science, Beni-Suef University, Beni-Suef
Radon Gas, CR-39 Detector; Biomedical Properties; Red Blood Cells; Osmotic Fragility; Viscosity
Purpose: To investigate the effect of inhalation radon gas (Rn) on the biomechanical properties of red blood cell of rats. Methods: 20 young healthy adult male albino rats were divided into equally 4 groups. The first group (0) served as control group, while the other three groups (I, II and III) were exposed to Rn gas inside a chamber for 3, 5 and 7 weeks. The biomechanical properties of red blood cell of rats was performed by determine the rheological properties of blood and the osmotic fragility of red blood cells (RBCs). Results: The Rn doses received by every group of rats were found to 34.84, 58.07 and 81.30 mSv for 3, 5 and 7 weeks respectively (based on 12 exposure hours per week). The obtained results indicate that the viscosity, consistency index, yield stress and aggregation index increase with Rn doses. The osmotic fragility curves of irradiated groups shift toward lower values of NaCl concentration. The dispersion of hemolysis (S) increased, at the same time an average osmotic fragility (H50%) decreased. Conclusion: The results indicates that the exposure to radon alters the mechanical properties of red blood cells membrane (permeability and elasticity) reflecting a change in its physiological properties. This mean that low levels of Rn gas are harmful to biological systems and the degree of damage was dose-dependent.
International Journal of Cancer Therapy and Oncology
2015-10-03
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.26
10.14319/ijcto.33.26
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.26/ijcto.33.26pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/99
2014-05-14T17:01:16Z
IJCTO:CONF
Energy dependence of polymer gels in the orthovoltage energy range
Roed, Yvonne; Department of Physics, University of Houston, Houston, TX, USA.
Tailor, Ramesh; Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX, USA.
Pinksy, L; Department of Physics, University of Houston, Houston, TX, USA.
Ibbott, Geoffrey; Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: Ortho-voltage energies are often used for treatment of patients’ superficial lesions, and also for small- animal irradiations. Polymer-Gel dosimeters such as MAGAT (Methacrylic acid Gel and THPC) are finding increasing use for 3-dimensional verification of radiation doses in a given treatment geometry. For mega-voltage beams, energy dependence of MAGAT has been quoted as nearly energy-independent. In the kilo-voltage range, there is hardly any literature to shade light on its energy dependence.Methods: MAGAT was used to measure depth-dose for 250 kVp beam. Comparison with ion-chamber data showed a discrepancy increasing significantly with depth. An over-response as much as 25% was observed at a depth of 6 cm.Results and Conclusion: Investigation concluded that 6 cm water in the beam resulted in a half-value-layer (HVL) change from 1.05 to 1.32 mm Cu. This amounts to an effective-energy change from 81.3 to 89.5 keV. Response measurements of MAGAT at these two energies explained the observed discrepancy in depth-dose measurements. Dose-calibration curves of MAGAT for (i) 250 kVp beam, and (ii) 250 kVp beam through 6 cm of water column are presented showing significant energy dependence.-------------------Cite this article as: Roed Y, Tailor R, Pinksy L, Ibbott G. Energy dependence of polymer gels in the orthovoltage energy range. Int J Cancer Ther Oncol 2014; 2(2):020232. DOI: 10.14319/ijcto.0202.32
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Roed
10.14319/ijcto.0202.32
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Roed/ijcto.0202.32pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Roed/ijcto.0202.32html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/115
2014-05-14T17:01:17Z
IJCTO:CONF
A plan quality classifier derived with overlap-wall-histogram of hollow organs for automatic IMRT plan quality control of prostate cancer cases
Song, Ting; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Tian, Zhen; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Zhou, Linghong; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Gu, Xuejun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Purpose: We developed a plan quality classification model to assess IMRT plan quality of prostate cancer patients for automatic plan quality control. Methods: For hollow organs such as rectum and bladder, dose-wall-histogram (DWH) was used to evaluate OAR dose sparing in our institution. Correspondingly, we proposed a new descriptor called overlap-wall-histogram (OWH) to describe the complex spatial relationship between PTV and a hollow organ. Two metrics calculated from the OWH and DWH are introduced to quantitatively evaluate the difficulty of patient geometry for planning and plan quality in terms of OAR sparing, respectively. A linear correlation between these two metrics was observed after plotting plan quality metric as a function of geometry difficulty metric studied from a database of prostate cases treated in our institution with acceptable plan quality. Thus, a fitting line was built acting as the boundary of high quality and poor quality plans. A query plan falling above the boundary is assessed as high quality, vice versa poor quality. Results: 15 prostate IMRT plans were used to test our model. One was identified as poor quality and the others were common-level. After re-planning all plans, the dose constraints for bladder wall W75 (percentage of wall receiving more than 75Gy), W70, W65 and W60 can be reduced by 3.34%, 3%, 6.99%, 6.54% for that poor quality plan and 1.11%, 0.95%, 1.45% and 1.81% averagely for the common-level quality group, without sacrificing PTV coverage and rectum dose sparing. Conclusion: An effective model was built to provide automatic IMRT plan quality control by evaluating hollow OAR dose sparing for prostate cancer patients. Furthermore, for the query plan with poor quality, potential improvement of plan quality can be estimated and a good reference plan with similar or harder geometry can be automatically chosen from our database to help guide the re-planning if necessary.---------------------------Cite this article as: Song T, Tian Z, Jia X, Zhou L, Jiang SB, Gu X. A plan quality classifier derived with overlap-wall-histogram of hollow organs for automatic IMRT plan quality control of prostate cancer cases. Int J Cancer Ther Oncol 2014; 2(2):020241. DOI: 10.14319/ijcto.0202.41
International Journal of Cancer Therapy and Oncology
2014-04-09
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info:eu-repo/semantics/publishedVersion
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http://www.ijcto.org/index.php/IJCTO/article/view/Song
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Song/ijcto.0202.41pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Song/ijcto.0202.41html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/294
2016-01-03T12:17:49Z
IJCTO:CONF
The value of Gleason score and prostate-specific antigen level in predicting the need for a baseline nuclear bone scan in patients with newly diagnosed 84 prostate cancer cases
Chorfi, Hind; Department of Nuclear Medicine, University Hospital Hassan II, FES
Ismaili Alaoui, Nadia; Department of Nuclear Medicine, University Hospital Hassan II, FES
Prostate Cancer; PSA level; Gleason Score; Bone Scan
Purpose: The objective of the present study was to correlate the prostate-specific antigen (PSA) level and Gleason score with the baseline bone scan results in patients with newly diagnosed prostate cancer and try to determine a group of patients whose risk of bone metastases is low enough to omit safely this staging modality.Methods: This retrospective study included 84 consecutive patients with newly diagnosed prostate cancer (Pca) who underwent a staging bone scan in Nuclear Medicine department between August 2013 and August 2014. Data were collected on age, bony pain, prostate-specific antigen (PSA) level and Gleason score, then, bone scan results were analyzed with respect to these parameters. Bone scan was recorded as positive, negative or equivocal. In case of equivocal lesions, a single-photon emission computed tomography combined with computed tomography (SPECT-CT) was performed allowing a better morphological precision. Results: The median age of the patients was 71, 38 years. Bone metastases were detected in 41 patients (49% of cases), bony pain was a reliable presenting sign of skeletal involvement. Both prostate-specific antigen (PSA) level and Gleason score were independent predictors of positive bone scan. However, the combination of these two parameters enhanced predictability of bone scan results. According to this study, the risk to develop a bone metastasis was very low in asymptomatic patients with PSA level < 20 ng/ml irrespective of the Gleason score or with PSA level < 30 ng/ml associated to a Gleason score < 7. Conclusion: The present study discourages the routine use of bone scan as a pre-treatment staging modality in asymptomatic patients with PSA level < 20 ng/ml irrespective of the Gleason score or with PSA level < 30 ng/ml associated to a Gleason score < 7, allowing considerable cost savings and decreasing time from diagnosis to treatment.
International Journal of Cancer Therapy and Oncology
2015-07-22
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.16
10.14319/ijcto.33.16
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.16/ijcto.33.16pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/110
2014-05-14T17:01:17Z
IJCTO:CONF
Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation
Xu, Yuan; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Bai, Ti; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Yan, Hao; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Ouyang, Luo; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Wang, Jing; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Pompos, Arnold; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Zhou, Linghong; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jiang, Steve; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Jia, Xun; Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
Medical Physics
Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT). We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC) simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1) FDK reconstruction using raw projection data; 2) Rigid Registration of planning CT to the FDK results; 3) MC scatter calculation at sparse view angles using the planning CT; 4) Interpolation of the calculated scatter signals to other angles; 5) Removal of scatter from the raw projections; 6) FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this article as: Xu Y, Bai T, Yan H, Ouyang L, Wang J, Pompos A, Zhou L, Jiang SB, Jia X. Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation. Int J Cancer Ther Oncol 2014; 2(2):020245. DOI: 10.14319/ijcto.0202.45
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Xu
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Xu/ijcto.0202.45
http://www.ijcto.org/index.php/IJCTO/article/view/Xu/ijcto.0202.45html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/127
2014-05-14T17:01:18Z
IJCTO:CONF
90Y PET/CT quantitative accuracy and image quality
Siman, Wendy; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Mawlawi, Osama R; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Kappadath, Cheenu S; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: To optimize 90Y-PET/CT image reconstruction for quantitative accuracy and optimal image quality.Methods: PET/CT scans of a NEMA IEC phantom (3GBq 90YCl2, sphere uptake ratio of ~7) were acquired on 4 GE (BGO:DSTE, DST & LYSO:DRX, D690) and 1 Siemens (LSO:mCT) scanners in 3D list mode with 30 min/bed; replayed to 20, 15, 10 min/bed. Iterative reconstruction parameters explored were SUB × IT (3 – 80) and post-reconstruction filters: transaxial: 5 – 25 mm cutoff & z-axis (GE only): std vs. heavy. The effects of PSF modeling and TOF correction were evaluated for D690 and mCT. VOIs were drawn inside spheres and in adjacent background regions. The accuracy of sphere activity concentration (AC in kBq/mL) and contrast to noise ratio (CNR) was calculated as function of SUB × IT. Reconstructed PET images were also evaluated qualitatively for sphere detectability and artifacts.Results: AC converged to 70 – 90% accuracy for 37 mm sphere and further degraded for smaller spheres. Spheres at max CNR might not reach AC convergence yet. Smaller spheres have slower convergence but reach CNR max together with other spheres. Scan duration did not strongly affect sphere convergence but shorter scans increased noise and reduced detectability; 13 mm spheres were not visible going from 30 to 15 min/bed. Heavy z-axis (GE) and transaxial filter with 10 – 15 mm cutoff helped suppress noise and increase sphere detectability at the expense of accuracy. Images with PSF+TOF corrections had higher sphere detectability and converged faster. Hot cluster artifacts 5 – 7 times the background were seen in some cases with SUB × IT near convergence and lower filtration.Conclusion: Accurate 90Y AC was not achieved even at convergence and noise is a major concern. 90YPET/CT reconstruction parameters are different than those for 18F and benefit substantially from PSF+TOF corrections. Optimum image quality and accurate AC may not be simultaneously achievable.----------------------------------------Cite this article as: Siman W, Mawlawi O, Kappadath SC. 90Y PET/CT quantitative accuracy and image quality. Int J Cancer Ther Oncol 2014; 2(2):020235. DOI: 10.14319/ijcto.0202.35
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Siman1
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Siman1/ijcto.0202.35pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Siman1/ijcto.0202.35html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/105
2014-05-14T17:01:16Z
IJCTO:CONF
Pretreatment CT texture features for prognostication in patient with Stage III Non-Small Cell Lung Cancer
Fried, David Vincent; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Tucker, SL; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Zhou, S; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Liao, ZX; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Ibbott, Geoffrey; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Court, Laurence; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: To determine whether CT texture features can yield prognostic information in addition to conventional prognostic factors in stage III non-small cell lung cancer (NSCLC).Methods: We conducted a retrospective review of 91 patients with stage III NSCLC treated with definitive chemoradiation. All patients received a four-dimensional (4D) CT simulation, where we utilized the average image (average-CT) and an expiratory image (T50-CT), and a diagnostic contrast enhanced CT image (CE-CT). A penalized cox regression model was used for covariate selection and model development. Models incorporating texture features from the 3 image types and clinical factors were compared to models incorporating clinical factors alone for overall survival (OS), local-regional control (LRC), and freedom from distant metastases (FFDM). Predictive Kaplan-Meier curves were generated using leave-one-out cross-validation. Stratification into low-risk and high-risk groups was based on a patient’s predicted outcome being greater or less than the median. Reproducibility of texture features was evaluated using test-retest scans from independent patients. The concordance correlation coefficient (CCC) was used to assess texture feature reproducibility and classification accuracy was used to assess reproducibility of texture features within the context of our models. Results: Models incorporating both texture and clinical features demonstrated a significant improvement in stratification compared to models using clinical features alone in cross-validated Kaplan-Meier curves in terms of OS (p = 0.046), LRC (p = 0.01), and FFDM (p = 0.005). The average CCC was 0.89, 0.91, and 0.67 for texture features extracted from the average-CT, T50-CT, and CE-CT, respectively. Incorporating reproducibility uncertainties within our model yielded 80.4 (SD = 3.7), 78.3 (SD = 4.0), and 78.8 (SD = 3.9) percent classification accuracy for OS, LRC, and FFDM, respectively. Conclusion: Pretreatment tumor texture may provide prognostic information in additional to routinely obtained clinical features. Reproducibility of CE-CT appears inferior to average-CT and T50-CT; however model classification accuracy rates of ~80% were still achieved.----------------------Cite this article as: Fried DV, Tucker SL, Zhou S, Liao ZX, Ibbott GS, Court LE. Pretreatment CT texture features for prognostication in patient with Stage III Non-Small Cell Lung Cancer. Int J Cancer Ther Oncol 2014; 2(2):020223. DOI: 10.14319/ijcto.0202.23
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Fried
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Fried/ijcto.0202.23pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Fried/ijcto.0202.23html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/121
2014-05-14T17:01:18Z
IJCTO:CONF
Are output measurements always necessary after CT tube replacement?
Stauduhar, Paul J; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Jones, Aaron Kyle; The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: TX regulations and the ACR require that CT radiation output be measured within 30 days of major service. The most common major service is tube replacement. We hypothesized that historical QC data could be used instead to determine if output measurements are necessary, reducing the need for costly output measurements.Methods: We reviewed 66 records of tube replacements to determine with what frequency output falls outside specifications. We also conducted an experiment to verify that clinically significant output changes could be identified by comparing image noise in historical QC data with the same data after tube replacement. We used 30 days of historical QC data to establish a baseline noise level and 95% confidence interval (CI) for individual noise measurements. To simulate output changes, we acquired phantom images with our QC protocol while manually changing output (mA). We acquired 10 images using the baseline output and 10 images at each different “output”. We evaluated individual images and subsets of images at each “output” to determine if the system was within the manufacturer’s specifications.Results: None of the 66 tube replacements resulted in an output change that exceeded specifications. Analysis of 30 days of historic QC data for our experimental system indicated a mean noise of 5.4 HU with 95% CI of 5.1 ‒ 5.7 HU. When using the mean noise of 10 images acquired at each of the varying outputs, we were able to identify, with 100% accuracy, images acquired at outputs outside manufacturer’s specifications.Conclusion: The results of our review of historical tube replacement data indicated the likelihood of output falling outside manufacturer’s specifications is low. Considering this, it is likely that by using QC data from programs required by regulation and the ACR physicists can reliably verify radiation output stability remotely instead of making physical measurements.--------------------Cite this article as: P Stauduhar, A Jones. Are output measurements always necessary after CT tube replacement? Int J Cancer Ther Oncol 2014; 2(2):020238. DOI: 10.14319/ijcto.0202.38
International Journal of Cancer Therapy and Oncology
2014-04-09
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Stauduhar
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Stauduhar/ijcto.0202.38pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Stauduhar/ijcto.0202.38html
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oai:ojs.ijcto.org:article/394
2016-07-16T10:06:47Z
IJCTO:CONF
A survey of paediatric CT radiation doses in two selected hospitals in Kampala, Uganda: a radiation safety concern
Kisembo, Harriet
Purpose: We describe radiation doses imparted to paediatric patients during Computerised (CT) scan examinations by estimation Weighted CT dose index (CTDIw) and Dose Length Product (DLP) and compare these doses with the International dose reference values.Methods: Demographic data and acquisition parameters of 257paediatric CT scans done using Multi-Slice CT (MSCT) and Dual Slice CT (DSCT) were collected from request forms and CT scan consoles. The values of CTDIw, CTDIvol and DLP were calculated using ImPACT (Imaging Performance and Assessment of Computed Tomography) dosimetry software for Philips MX-1800 scanner and GE Hispeed Dual scanner. Data was analysed using mean, range, 3rd quartile, as well as chi square.Results: The commonest indication was head injury with the majority patient aged 0-4 years and 10-14 years for MSCT and DSCT, respectively. There were significantly higher doses imparted by MSCT compared to DSCT on both the head CTDIw (mGy) (40 vs 22, p = 0.000), CTDIvol (mGy) (60 vs 7, p = 0.000), DLPmGy.cm (1022 vs 114, p = 0.000) and body CTDIw (mGy) (41 vs 18, p =0.000), CTDIvol (mGy) (27 vs 6 p-value=0.000) and DLP (782 vs 73 p-value=0.001) respectively. Paediatric 3rd quartile values for CTDIvol (mGy) (57.7 vs 31) 0-1 year, (74.5 vs 47) 4-7 years and DLP mGy.cm (1068 vs 333) 0-1 year and (1168 vs 374) 4-6 years respectively for MSCT were higher than the recommended international values. The calculated CTDIvol for the head were significantly higher than the values displayed on the console (p-value=0.000, 95%CI) for MSCT.Conclusion: The radiation dose values for CTDIw, CTDIvol and DLP for MSCT were significantly higher than those for DSCT and other countries which raise a radiation safety concern. Studies to establish the factors responsible for these high doses are recommended.
International Journal of Cancer Therapy and Oncology
2015-09-15
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.27
10.14319/ijcto.33.27
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.27/ijcto.3327pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/100
2014-05-14T17:01:16Z
IJCTO:CONF
Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volume modulated arc therapy (VMAT)
Casey, Kevin; Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Wang, Pei-Fong; Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Tung, Samuel; Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Rosenthal, David; Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Medical Physics
Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT).Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor site. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs and a second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient’s treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the deformed low neck contours.Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3.Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT.-------------------------------------------Cite this article as: Casey K, Wang P, Tung S, Rosenthal D. Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volume modulated arc therapy (VMAT). Int J Cancer Ther Oncol 2014; 2(2):020218. DOI: 10.14319/ijcto.0202.18
International Journal of Cancer Therapy and Oncology
2014-04-08
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info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Casey
10.14319/ijcto.0202.18
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Casey/ijcto.0202.18pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Casey/ijcto.0202.18html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/116
2014-05-14T17:01:17Z
IJCTO:CONF
Voxel-based partial volume correction for accurate quantitative voxel values
Mikell, Justin; Department of Imaging Physics, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center Houston, TX, USA.
Kappadath, S Cheenu; Department of Imaging Physics, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center Houston, TX, USA.
Medical Physics
Purpose: The accuracy of voxelized information in emission imaging is limited by spatial resolution (FWHM = 2.35σ) producing biases for objects smaller than 3 FWHM. If the signal distribution is non‐uniform within 3σ of the voxel of interest then equilibrium does not exist and partial volume effect (PVE) compromises voxel accuracy. We propose a mathematical model to improve the accuracy of quantitative images of arbitrary distribution by bounding true voxel signal and estimating PVE for each voxel.Methods: A monotonically increasing parametric dataset is created for each voxel of an emission image by radial integration from the voxel center to radius = 6σ. Each cumulative integration plot from r = 3σ to 6σ is fit to a function A*4π /3*r3 + B*ΔV derived assuming a local uniform signal distribution (A) where ΔV is the voxel volume. The constant BΔV represents the converged within 3σ integral of PVE. B > 0 implies spill‐out, B < 0 spill‐in, and B = 0 no PVE. We tested the proposed model on simulations of 1D&2D datasets containing known signal distributions and 18F‐PET/CT images of a 6cc lung lesion and bladder.Results: Signal accuracy was > 99% in simulated 1D & 2D datasets. For the tumor, the original maximum value was 10kBq/ml. We obtained A = 3.5kBq/ml and B = 14kBq/ml for a total of 17.7kBq/ml. This yields (A+B)/original = 1.8 indicating substantial spill‐out of ~80% and a large error for the original voxel value. For a voxel in the center of the bladder, the original value was 46kBq/ml with A = 44kBq/ml, B = 7kBq/ml. (A+B)/original = 1.11 indicating near‐equilibrium at center of bladder and low spill-out of ~11% as expected. Local signal images (A) resemble low‐pass filtered original image and (B) shows the magnitude and direction of PVE. Conclusion: A new mathematical model to estimate the accuracy of voxels in quantitative images of arbitrary distribution has been developed. Analysis of additional patients is underway.-------------------------------------Cite this article as: Mikell J, Kappadath SC. Voxel-based partial volume correction for accurate quantitative voxel values. Int J Cancer Ther Oncol 2014; 2(2):020229. DOI: 10.14319/ijcto.0202.29
International Journal of Cancer Therapy and Oncology
2014-04-09
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info:eu-repo/semantics/publishedVersion
application/pdf
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http://www.ijcto.org/index.php/IJCTO/article/view/Mikell1
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Mikell1/ijcto.0202.29pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Mikell1/ijcto.0202.29html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/293
2016-01-03T12:17:49Z
IJCTO:CONF
Measurement of radium isotope activities in reservoir and spring water in the Cameroon Central Region
Marie, Rose Lydie; Department of Radiation Emergencies, National Radiation Protection Agency, Yaoundé
Hakam, Oum Keltoum; Department of Physics, University Ibn Tofaïl, Kenitra
Choukri, Abdelmajid; Department of Physics, University Ibn Tofaïl, Kenitra
Nuclear Physics
Water; Natural Radionuclide; Concentration; Gamma Spectrometry
Purpose: To determine the activities of 226Ra and 228Ra in the reservoir and spring water samples respectively during the dry and the rainy seasons; and to calculate the annual intake Ii (Bq/y) for each type of water samples. Methods: Using both well calibrated Canberra NaI(Tl) and HPGe detector systems, it was possible to determine the average specific activity of those radium’s isotopes in water samples which were collected in 2010, from Reservoirs and springs in Cameroon central region including Ngoaekelle, Minboman, Etoudi and Njoungolo. Results: The average specific activity values obtained for 226Ra and 228Ra in reservoir water samples were 8.76 ± 3.50 BqL-1 and 0.64 ± 0.28 BqL-1 during the dry season and, 8.24 ±3.48 BqL-1 and 0.58 ± 0.24 BqL-1 during the rainy season respectively. For spring water, the average values were 3.50 ± 0.63 BqL-1 and below 0.0002 BqL-1 (detection limit of 228Ra in water) during the dry season; 3.20 ± 0.60 BqL-1 and below 0.0002 BqL-1 (detection limit of 228Ra in water) during the rainy season respectively. Assuming that the volume of drinking water for adult is 2.5 litres per day, the average annual intakes of 226Ra and 228Ra through ingestion in these water samples were 7702 Bq/y and 575 Bq/y for reservoir water; 2993 Bq/y and < 0.25 for spring water respectively. Conclusion: The results have indicated that the annual intake by the population of sampling region as a result of 226Ra in these drinking waters is 7.7 × 103Bq/y more than the maximum limit fixed by ICRP which is 7 × 103 Bq/y. There is a need for regular monitoring the radiological water quality aspect in this region.
International Journal of Cancer Therapy and Oncology
2015-07-23
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.17
10.14319/ijcto.33.17
International Journal of Cancer Therapy and Oncology; Vol 3, No 3 (2015): July - September
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/ijcto.33.17/ijcto.33.17pdf
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/111
2014-05-14T17:01:17Z
IJCTO:CONF
Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy
Lewis, Dana J; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Summers, Paige A; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Followill, David S; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Sahoo, Narayan; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Mahajan, Anita; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX, USA.
Stingo, Francesco C; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX, USA.
Kry, Stephen F; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX, USA.
Medical Physics
Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC) Houston QA Center (formerly RPC).Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS), and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD)-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP) and Hounsfield unit (HU) values. Each material was CT scanned at 120 kVp, and the RSP was obtained from depth ionization scans using the Zebra multi-layer ion chamber (MLIC) at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU.Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc.), solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%.Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma analysis criterion for the film planes.--------------------------------------Cite this article as: Lewis DJ, Summers PA, Followill DS, Sahoo N, Mahajan A, Stingo FC, Kry SF. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy. Int J Cancer Ther Oncol 2014; 2(2):020227. DOI: 10.14319/ijcto.0202.27
International Journal of Cancer Therapy and Oncology
2014-04-09
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info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Lewis
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Lewis/ijcto.0202.27pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Lewis/ijcto.0202.27html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/128
2014-05-14T17:01:18Z
IJCTO:CONF
Deformable image and dose registration evaluation using two commercial programs
Tuohy, Rachel; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Bosse, Courtney; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Mavroidis, Panayiotis; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Shi, Zheng; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Crownover, Richard; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Papanikolaou, Niko; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Stathakis, Sotirios; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Cancer Therapy and Research Center, San Antonio, TX, USA.
Medical Physics
Purpose: To evaluate the daily dose delivered to the patients using daily imaging.Methods: Thirty (n = 30) patients that were previously treated in our clinic (10 prostate, 10 SBRT lung and 10 abdomen) were used in this study. The patients’ plans were optimized and calculated using the Pinnacle treatment planning system. The daily CBCT scans were retrieved and imported into the Velocity and RayStation software along with the corresponding planning CTs, structure sets and 3D dose distributions. In addition, the critical structures were contoured on each CBCT by the prescribing physician and were included in the evaluation of the daily delivered dose. After registering each CBCT scan to the planning CT using deformable registration, the dose volume histograms (DVH) for the organs at risk (OAR) and the respective planning target volumes (PTV) were calculated in Velocity and Raystation.Results: For the prostate patients, we observed daily volume changes for the bladder, rectum and sigmoid. The DVH analysis for those patients showed variation in the sparing of the critical structures while PTV coverage showed no significant changes. Similar results were observed for patients with abdominal targets. In contrast, in SBRT lung patients, the DVH for the critical structures and the PTV were comparable to those from the initial treatment plan. By using daily CBCT dose reconstruction, we proved PTV coverage for prostate and abdominal targets is adequate. However, there is significant dosimetric change for the OAR. These changes were random with no apparent trending. For lung SBRT patients, the delivered daily dose for both PTV and OAR is comparable to the planned dose with no significant differences.Conclusion: Daily tracking of the delivered dose is feasible. The doses can be evaluated only if the OARs have been segmented taken into account any daily anatomical changes and not by deformation of the structures along.-------------------Cite this article as: Tuohy R, Bosse C, Mavroidis P, Shi Z, Crownover R, Papanikolaou N, Stathakis S. Deformable image and dose registration evaluation using two commercial programs. Int J Cancer Ther Oncol 2014; 2(2):020242. DOI: 10.14319/ijcto.0202.42
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Tuohy
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Tuohy/ijcto.0202.42pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Tuohy/ijcto.0202.42html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/106
2014-05-14T17:01:16Z
IJCTO:CONF
Evaluation of three commercial metal artifact reduction methods for CT simulations in radiation therapy
Huang, Jessie Y; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Kerns, James R; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Nute, Jessica L; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX, USA.
Liu, Xinming; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX, USA.
Stingo, Francesco C; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Followill, David S; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Mirkovic, Dragan; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Howell, Rebecca M; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Kry, Stephen F; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Medical Physics
Purpose: To evaluate the success of three commercial metal artifact reduction methods (MAR) in the context of radiation therapy treatment planning.Methods: Three MAR strategies were evaluated: Philips O-MAR, monochromatic imaging using Gemstone Spectral Imaging (GSI) dual energy CT, and monochromatic imaging with metal artifact reduction software (GSI-MARs). The Gammex RMI 467 tissue characterization phantom with several metal rods and two anthropomorphic phantoms (pelvic phantom with hip prosthesis and head phantom with dental fillings), were scanned with and without metals (baseline). Each MAR method was evaluated based on CT number accuracy, metal size accuracy, and reduction in the severity of streak artifacts. CT number difference maps between the baseline and metal scan images were calculated, and the severity of streak artifacts was quantified using the percentage of pixels with > 40 HU error (“bad pixels”).Results: Philips O-MAR generally reduced HU errors in the RMI phantom. However, increased errors and induced artifacts were observed for lung materials. GSI monochromatic 70keV images generally showed similar HU errors as conventional 120kVp imaging, while 140keV images reduced HU errors. All the imaging techniques represented the diameter of a stainless steel rod to within ±1.6mm (2 pixels). For the hip prosthesis, O-MAR reduced the average % bad pixels from 47% to 32%. For GSI 140keV imaging, the % bad pixels was reduced from 37% to 29% compared to 120kVp imaging, and GSI-MARs further reduced it to 12%. For the head phantom, none of the MAR methods was particularly successful.Conclusion: O-MAR resulted in consistent artifact reduction but exhibited induced artifacts for metals located near lung tissue. GSI imaging at 140keV gave consistent reduction in HU errors and severity of artifacts. GSI-MARs at 140keV was the most successful MAR method for the hip prosthesis but exhibited induced artifacts at the edges of metals in some cases.---------------------------------Cite this article as: Huang JY, Kerns JR, Nute JL, Liu X, Stingo FC, Followill DS, Mirkovic D, Howell RM, Kry SF. Evaluation of three commercial metal artifact reduction methods for CT simulations in radiation therapy. Int J Cancer Ther Oncol 2014; 2(2):020224. DOI: 10.14319/ijcto.0202.24
International Journal of Cancer Therapy and Oncology
2014-04-09
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http://www.ijcto.org/index.php/IJCTO/article/view/Huang
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Huang/ijcto.0202.24pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Huang/ijcto.0202.24html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
oai:ojs.ijcto.org:article/122
2014-05-14T17:01:18Z
IJCTO:CONF
Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients
Stanley, Dennis N; University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Narayanasamy, G; University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Breton, C
Papanikolaou, Niko; University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Gutierrez, Alonso N; University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Medical Physics
Purpose: To evaluate the low contrast detectability sensitivity among 4-slice, 8-slice and 16-slice CT units using various mAs settings. Findings of the study may elucidate the most optimal imaging parameter for stereotactic radiosurgery (SRS) patients who are not MRI compatible.Methods and Materials: Low contrast targets in the CATPHAN phantom (model: CTP 504, The Phantom Laboratory) were imaged on a 4-slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) and a 16- slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) in 8-slice and 16-slice mode. The CATPHAN CTP515 low contrast targets of size 15, 9, 8, 7, 6, 5, 4, 3 and 2 mm for each contrast difference of 1%, 0.5% and 0.3% from the water-equivalent background was imaged using a SRS protocol. Two image sets per setting were acquired for mAs parameters of 300, 350 and 440. Images were evaluated in a blind study by three independent reviewers.Results: Using 300,350 and 440mAs settings on the 4-slice scanner, the average smallest diameters recorded at 1% contrast were 5 ± 1 mm, 5 ± 1 mm and 5 ± 0 mm and at 0.5% were 7 ± 2 mm, 7 ± 1 mm and 6 ± 1 mm. For the 8 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 0 mm, 6 ± 0 mm and 5 ± 0 mm, and at 0.5% were 12 ± 3 mm, 9 ± 1 mm and 6 ± 1 mm. For the 16 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 1 mm, 7 ± 1 mm and 6 ± 1 mm, and at 0.5% were 11 ± 3 mm, 8 ± 1 mm and 8 ± 1 mm. A difference was observed between the 4 and 8 - slice scanners at 300mAs (p < 0.01) for each contrast level as well as the 4 and 16 slice at 440 (p < 0.01) and 350 (p < 0.01) mAs. Additionally, a difference was observed between each mAs for the 8 slice at 1% (p < 0.01) and 0.5% (p < 0.01) contrast.Conclusion: Results demonstrate consistently improved low contrast detectability as mAs was increased. CT simulation imaging parameters can be optimized to improve low contrast sensitivity for non MRI compatible SRS patients.----------------Cite this article as: Stanley D, Narayanasamy G, Breton C, Papanikolaou N, Gutierrez AN. Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients. Int J Cancer Ther Oncol 2014; 2(2):020237. DOI: 10.14319/ijcto.0202.37
International Journal of Cancer Therapy and Oncology
2014-04-08
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
text/html
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley1
International Journal of Cancer Therapy and Oncology; Vol 2, No 2 (2014): April - June
23304049
eng
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley1/ijcto.0202.37pdf
http://www.ijcto.org/index.php/IJCTO/article/view/Stanley1/ijcto.0202.37html
Authors who publish with this journal agree to the following terms:Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).