Fujimoto Sachie, Ono Kaoru, Furukawa Kengo, Kudo Tsuyoshi, Akagi Yukio, Koyama Tadashi, Hirokawa Yutaka, Kawai Shintarou, Nakashima Takeo
State of the Art Treatment Center, Hiroshima Heiwa Clinic.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2012;68(7):825-34. doi: 10.6009/jjrt.2012_jsrt_68.7.825.
The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber. The dosimetric impact of treatment planning for 3DCRT and IMRT of prostate cancer for ten clinical cases using two MLC systems was evaluated quantitatively. 3DCRT was divided to 3DCRT(middle) as fitting at middle of leaf tip and 3DCRT(outside) as fitting at outside of leaf tip. The leaf transmission factor and DLG of HD120 MLC for 6 and 10 MV X-ray decreased by 0.2% and 1 mm, respectively, compared to M120 MLC. The mean conformity index of PTV of treatment planning for prostate 3DCRT(middle), 3DCRT(outside) , and IMRT decreased by 0.9%, 6.6%, and 0.9% and the mean homogeneity index increased 2.3%, 13.0%, and 4.2%, respectively. The mean V20, V40, and V65 decreased by 2.4%, 6.6%, and 4.5% for bladder and 3.3%, 6.1%, and 5.9% for rectum, respectively. The results of this work demonstrated that the dose conformity of PTV improved and the dose of bladder and rectum decreased for 3DCRT and IMRT of prostate cancer using HD120 MLC compared to M120 MLC, because of reduction of leaf width, leaf transmission, and rounded leaf end transmission.
本研究的重点是使用叶宽为2.5 mm的瓦里安/ BrainLAB 120叶高清多叶准直器（HD120 MLC）和叶宽为5 mm的瓦里安120叶千年多叶准直器（M120 MLC），评估前列腺癌三维适形放疗（3DCRT）和调强放疗（IMRT）治疗计划的剂量学影响。我们使用 Farmer电离室测量了两种多叶准直器（MLC）系统的叶片透射率和剂量学叶片间隙（DLG）。定量评估了使用两种MLC系统对10例临床病例进行前列腺癌3DCRT和IMRT治疗计划的剂量学影响。3DCRT分为3DCRT（中间），即拟合在叶片尖端中间，以及3DCRT（外部），即拟合在叶片尖端外部。与M120 MLC相比，HD120 MLC在6和10 MV X射线下的叶片透射因子和DLG分别降低了0.2%和1 mm。前列腺3DCRT（中间）、3DCRT（外部）和IMRT治疗计划PTV的平均适形指数分别降低了0.9%、6.6%和0.9%，平均均匀性指数分别提高了2.3%、13.0%和4.2%。膀胱的平均V20、V40和V65分别降低了2.4%、6.6%和4.5%，直肠的平均V20、V40和V65分别降低了3.3%、6.1%和5.9%。本研究结果表明，与M120 MLC相比，使用HD120 MLC进行前列腺癌3DCRT和IMRT时，PTV的剂量适形性得到改善，膀胱和直肠的剂量降低，这是由于叶宽减小、叶片透射率降低以及叶片末端圆形透射率降低所致。
Zotero 插件