Inverse planning approach for 3-D MRI-based pulse-dose rate intracavitary brachytherapy in cervix cancer
Inverse planning approach for 3-D MRI-based pulse-dose rate intracavitary brachytherapy in cervix cancer
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DOI：
10.1016/j.ijrobp.2007.07.2321
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发表时间：
2007-11-01
影响因子：
7
通讯作者：
Haie-Meder, Christine
中科院分区：
文献类型：
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作者：
Chajon, Enrique;Dumas, Isabelle;Haie-Meder, Christine
目的：评价反向规划模拟退火法(IPSA)软件在宫颈癌MRI腔内脉冲剂量率近距离放射治疗中剂量分布的优化作用。方法与材料：选择30例采用定制阴道模型的宫颈癌患者。将IPSA方法获得的剂量-体积参数与经典的人工优化方法(MOM)进行了比较。根据妇科近距离放射治疗小组/欧洲治疗放射学和肿瘤学学会的建议，描绘了目标体积和危险器官。由于脉冲剂量率方案是基于低剂量率的临床经验，因此要求停留时间值尽可能均匀。为实现这一目标，对IPSA程序进行了不同的修改。结果：由IPSA算法计算的第一剂量分布提出了停留时间位置的非均匀分布。当应用约束时，两种方法计算的平均值D90、D100和V100没有显著差异。对于膀胱，根据MOM计算的ICRU参考点的剂量与IPSA方法计算的剂量有显著差异(平均分别为58.4Gyvs.55Gy.p=0.0001)。对于直肠，用IPSA方法计算的ICRU参考点的剂量也明显较低。结论：逆向计划方法为剂量分布的优化提供了快速、自动的解决方案。然而，直接使用IPSA在停留时间值上产生了显著的异质性。因此，建议在使用反向优化工具进行新剂量学规则的临床相关性研究时要谨慎。(C)2007年爱思唯尔公司。
Purpose: The purpose of this study was to evaluate the inverse planning simulated annealing (IPSA) software for the optimization of dose distribution in patients with cervix carcinoma treated with MRI-based pulsed-dose rate intracavitary brachytherapy.Methods and Materials: Thirty patients treated with a technique using a customized vaginal mold were selected. Dose-volume parameters obtained using the IPSA method were compared with the classic manual optimization method (MOM). Target volumes and organs at risk were delineated according to the Gynecological Brachytherapy Group/European Society for Therapeutic Radiology and Oncology recommendations. Because the pulsed dose rate program was based on clinical experience with low dose rate, dwell time values were required to be as homogeneous as possible. To achieve this goal, different modifications of the IPSA program were applied.Results: The first dose distribution calculated by the IPSA algorithm proposed a heterogeneous distribution of dwell time positions. The mean D90, D100, and V100 calculated with both methods did not differ significantly when the constraints were applied. For the bladder, doses calculated at the ICRU reference point derived from the MOM differed significantly from the doses calculated by the IPSA method (mean, 58.4 vs. 55 Gy respectively; p = 0.0001). For the rectum, the doses calculated at the ICRU reference point were also significantly lower with the IPSA method.Conclusions: The inverse planning method provided fast and automatic solutions for the optimization of dose distribution. However, the straightforward use of IPSA generated significant heterogeneity in dwell time values. Caution is therefore recommended in the use of inverse optimization tools with clinical relevance study of new dosimetric rules. (C) 2007 Elsevier Inc.