Detailed dosimetric evaluation of intensity-modulated radiation therapy plans created for stage C prostate cancer based on a planning protocol
Detailed dosimetric evaluation of intensity-modulated radiation therapy plans created for stage C prostate cancer based on a planning protocol
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DOI：
10.1007/s10147-011-0324-1
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发表时间：
2012-10-01
影响因子：
3.3
通讯作者：
Hiraoka, Masahiro
中科院分区：
文献类型：
--
作者：
Norihisa, Yoshiki;Mizowaki, Takashi;Hiraoka, Masahiro
调强放射治疗（IMRT）是一种精确的放射治疗方法，对靶区具有较高的适形性。尽管许多研究报告了临床结局，但迄今为止尚未提及详细的治疗计划结果。本研究的目的是评估我们的局部晚期前列腺癌的调强放射治疗计划的剂量规格，回顾性分析了2003年9月至2005年12月间77例临床应用调强放射治疗计划，患者在俯卧位接受78戈伊的照射。详细评价了剂量体积直方图输出的剂量测定数据，平均剂量+/- A标准差、均匀性指数和与计划靶体积（PTV）的符合性指数分别为78.3 +/- A 0.7戈伊（100.4 +/- A 0.9%）、13.7 +/- A 3.0和0.83 +/- A 0.04。对于临床靶体积，平均剂量为80.3 +/- A 0.7戈伊（102.9 +/- A 0.9%）。直肠壁的V40、V60和V70戈伊分别为58.3 +/- A 2.8、29.6 +/- A 2.7和15.2 +/- A 3.0%。由于肠道位置的限制改变了PTV的剂量指数，因此在肠道向下移位的患者中遇到了计划困难。在许多情况下，需要额外的肠道优化参数来满足对风险器官的约束。然而，主要的偏差可以通过逆向计划与计算机优化来避免。IMRT允许创建可接受的和实用的治疗计划，局部晚期前列腺癌。关于详细剂量测定评价的报告是强制性的，用于解释未来的临床结局。
Intensity-modulated radiation therapy (IMRT) has been employed as a precision radiation therapy with higher conformity to the target. Although clinical outcomes have been reported for many investigations, detailed treatment planning results have not been mentioned to date. The aim of this study was to evaluate the dose specifications of our IMRT treatment plans for locally advanced prostate cancer.Seventy-seven clinically applied IMRT plans treated between September 2003 and December 2005, in which patients were irradiated with 78 Gy in the prone position, were retrospectively analyzed. Dosimetric data output from dose volume histograms were evaluated in detail.The mean dose +/- A standard deviation, homogeneity index, and conformity index to the planning target volume (PTV) were 78.3 +/- A 0.7 Gy (100.4 +/- A 0.9%), 13.7 +/- A 3.0, and 0.83 +/- A 0.04, respectively. For the clinical target volume, the mean dose was 80.3 +/- A 0.7 Gy (102.9 +/- A 0.9%).The V40, V60, and V70 Gy of the rectal wall were 58.3 +/- A 2.8, 29.6 +/- A 2.7, and 15.2 +/- A 3.0%, respectively. Planning difficulties were encountered in patients whose bowels were displaced downward, as constraints imposed by the bowel position altered the dose index of the PTV. In many cases, additional bowel optimization parameters were required to satisfy constraints for organs at risk. However, major deviation could be avoided by inverse planning with computer optimization.IMRT allowed the creation of acceptable and practical treatment plans for locally advanced prostate cancer. Reports regarding detailed dosimetric evaluations are mandatory for interpreting clinical outcomes in the future.