Investigation the impact of maximum control point on dose calculation in Eclipse treatment planning system for lung SBRT
Purpose: Choosing an appropriate parameter on the computerized treatment planning systems (TPSs) influences on the accuracy of dose calculation. Several dosimetric parameters have been studied to achieve a more accurate dose and qualitative plan. The purpose of this study was to determine the impact of maximum control point on the dose calculation on Eclipse TPSs for lung Stereotactic Body Radiation Therapy (SBRT) considering the plan quality, the computation time and the treatment file size.
Methods: Dose distributions for the 8 lung SBRT plans with varying maximum control point of 64, 166, and 320 were calculated by Eclipse TPSs with flattening filter free (FFF) beam. The treatment dose was prescribed at 85% isodose level of 54 Gy to the planning target volume (PTV). The dosimetric impact can be evaluated from target coverage, conformity index (CI), homogeneity index (HI), and organ at risk (OAR) doses, while the computation time and the file storage space were compared with the recommended number of control point.
Results: The use of 64 control points per subfields tended to increase the dose at PTV and OARs comparing with the 166 and 320 control point plans, while the HI and CI values were similar. The average increases of OARs doses including the spinal cord, heart, esophagus and total lung depended on the photon beam energy. The higher average control point (AVG) number leaded to increase the computation time and the file size for both 6X-FFF and 10X-FFF photon beams. The correlations between AVG and plan storaage space were observed in the same ratio as the computation time.
Conclusion: Using the minimal number of control point, the quantitative analysis in the PTV and OARs showed no clinically significant variation in dose, therefore choosing an optimal number of fixed control points leaded to balance the plan quality, the computation time and the file size.
Kong FM, Zhao J, Wang J, et al. Radiation dose effect in locally advanced non-small cell lung cancer. J Thorac Dis. 2014;6(4):336-47.
Huang B, Wu L, Lin P, et al. Dose calculation of Acuros XB and Anisotropic Analytical Algorithm in lung stereotactic body radiotherapy treatment with flattening filter free beams and the potential role of calculation grid size. Radiat Oncol. 2015;10:53.
Park JY, Kim S, Park HJ. Optimal set of grid size and angular increment for practical dose calculation using the dynamic conformal arc technique: a systemic stereotactic body radiation therapy. Radiat Oncol. 2014;9:5.
Chung H, Jin H, Palta J, et al. Dose variations with varying calculation grid size in head and neck IMRT. Phys Med Biol. 2006;51(19):4841-56.
Goraj A, De Boer SF. Impact of the number of control point has on isodose distributions in a dynamic multileaf collimator intensity modulated radiation therapy delivery. Med Dosim. 2014;37:412-6.
Convery DJ, Webb S. Generation of discrete beam-intensity modulation by dynamic multileaf collimator under minimum leaf separation constraint. Phys Med Biol. 1998;43(9):2521-38.
Varian medical system. Eclipse 10 inverse planning administration and physics rev. 6.1.1. 2011.
Benedict SH, Yenice KM, Followill D, et al. Stereotactic body radiation therapy: the report of AAPM task group 101. Med Phys. 2010;37(8):4078-101.
Shaw E, Kline R, Gillin M, et al. Radiation therapy oncology group; radiosurgery quality assurance guidelines. Int J Radiat Oncol Biol Phys. 1993;27(5):1231-9.
Feuvret L, Noel G, Mazeron JJ, et al. Conformity index: a review. Int J Radiat Oncol Biol Phys. 2006;64(2): 333-42.
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International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)
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