Multileaf-collimator daily quality assurance of Vero4DRT system: our one-year experience

Hideharu Miura, Shuichi Ozawa, Shintaro Tsuda, Kiyoshi Yamada, Yasushi Nagata

Abstract


Purpose: We assessed the daily quality assurance (QA) of multi-leaf collimator (MLC) using the Vero4DRT system.

Methods: As part of daily MLC QA, the irradiation field was set to 100 × 150 mm2 with a gantry angle of 0 º. Only the leaf positioning error values only were displayed. We developed an in-house program to easily acquire these values using an open source optical character recognition engine. This test was implemented between 24 August 2015 and 23 August 2016.

Results: The maximum leaf positioning error was 0.40 mm in both banks. In addition, the maximum deviation was 0.10 mm in both banks. The average and standard deviation for left and right banks were 0.19 mm ± 0.11 mm and 0.15 mm ± 0.09 mm, respectively. In our one-year measurement, the leaf positioning error was less than 0.50 mm. Therefore, if the leaf position error for daily MLC QA exceeded 0.50 mm, then an external intervention is required.

Conclusion: The daily MLC QA of our one-year evaluation of the Vero4DRT system demonstrates an excellent leaf accuracy and reproducibility, thereby giving confidence in the quality of the treatment.


Keywords


Multileaf-collimator daily quality assurance of Vero4DRT system: Our one-year experience

Full Text:

PDF

References


LoSasso T, Chui CS, Ling CC. Physical and dosimetric aspects of a multileaf collimator system used in the dynamic mode for implementing intensity modulated radiotherapy. Med Phys. 1998;25:1919-27.

Kuperman VY, Lam WC. Improving delivery of segments with small MU in Step-and-Shoot IMRT. Med Phys. 2006;33;1067-73.

Sastre-Padro M, van der Heide UA, Welleweerd H. An accurate calibration method of the multileaf collimator valid for conformal and intensity modulated radiation treatments. Phys Med Biol. 2004;49:2631–43.

Sastre-Padro M, Welleweerd J, Malinen E, et al. Consequences of leaf calibration errors on IMRT delivery. Phys Med Biol. 2007;52:1147–56.

Chui CS, Spirou S, LoSasso T. Testing of dynamic multileaf collimation. Med Phys. 1996;23:635–41.

Vieira SC, Dirkx MLP, Pasma KL, et al. Fast and accurate leaf verification for dynamic multileaf collimation using an electronic portal imaging device. Med Phys. 2002;29:2034–40.

Mamalui-Hunter M, Li H, Low DA. MLC quality assurance using EPID: a fitting technique with subpixel precision. Med Phys 2008;35:2347–55.

Kamino Y, Takayama K, Kokubo M, et al. Development of a four-dimensional image-guided radiotherapy system with a gimbaled X-ray head. Int J Radiat Oncol Biol Phys. 2006;66:271–78.

Kamino Y, Miura S, Kokubo M, et al. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. Med Phys. 2007;34:1797–808.

Klein EE, Hanley J, Bayouth J, et al. Task Group 142 report: quality assurance of medical accelerators. Med Phys. 2009;36:4197–212.

Kutcher GJ, Coia L, Gillin M, et al. Comprehensive QA for radiation oncology: report of AAPM Radiation Therapy Committee Task Group 40. Med Phys. 1994;21:581–618.

Nakamura M, Sawada A, Ishihara Y, et al. Dosimetric characterization of a multileaf collimator for a new four-dimensional image-guided radiotherapy system with a gimbaled x-ray head, MHI-TM2000. Medical Physics 2010;37: 4684-91.

Tesseract Homepage. Available at https://code.google.com/p/tesseract-ocr/

Palta JR, Mackie TR. Intensity-modulated radiation therapy: the state of the art. Madison. Medical Physics Publishing, 2003.

Parent L, Seco J, Evans PM, et al. Evaluation of two methods of predicting MLC leaf positions using EPID measurements. Med Phys. 2006;33:3174-82.

Bayouth JE, Wendt D, Morrill SM. MLC quality assurance techniques for IMRT applications. Med Phys.2003;30:743–50

Okumura M, Obata Y, Shimomura K, et al. The effect of gantry and collimator angles on leaf limited velocity and position in dynamic multileaf collimator intensity-modulated radiation therapy. Phys Med Biol. 2010;55:3101-13.




DOI: http://dx.doi.org/10.14319/ijcto.51.12

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

------------------------------------------------------------

International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)

© International Journal of Cancer Therapy and Oncology (IJCTO)

To make sure that you can receive messages from us, please add the 'ijcto.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.

------------------------------------------------------------

Number of visits since October, 2013
AmazingCounters.com