Impact of interfractional anatomical variation and setup correction methods on interfractional dose variation in IMPT and VMAT plans for pancreatic cancer patients: A planning study
Impact of interfractional anatomical variation and setup correction methods on interfractional dose variation in IMPT and VMAT plans for pancreatic cancer patients: A planning study
复制标题
DOI：
10.1002/acm2.12883
复制
发表时间：
2020-04-30
影响因子：
2.1
通讯作者：
Mizowaki, Takashi
中科院分区：
文献类型：
--
作者：
Ashida, Ryo;Nakamura, Mitsuhiro;Mizowaki, Takashi
目的探讨屏气条件下胰腺癌分次治疗中解剖结构的改变和摆位校正方法对剂量分布的影响。方法采用3种不同射束排列的强度调制质子治疗（IMPT）计划和1种体积调制弧形治疗（VMAT）计划，分别对10例胰腺癌患者进行了10次剂量治疗，并对治疗效果进行了评价。为10名患者制定了30次54戈伊的计划，这些患者接受了3次额外的CT扫描，间隔1-2周。在每例患者中，使用骨匹配（BM）和器官匹配（OM）方法将额外的CT集严格配准到模拟CT集。重新计算的剂量分布和剂量体积指数的额外的CT集，使用BM或OM方法进行了比较与模拟value.Results差异的总肿瘤体积D-98%值从模拟集的平均范围从-0.8到-5.9%。此外，对于两个IMPT计划，OM的变化大于BM。同时，在两个IMPT计划和VMAT计划上，OM显著改善了从大体肿瘤体积各向同性扩大5 mm的区域中D-98%值的差异。在危险的器官，剂量-体积指数显着改善OM只在十二指肠上所有plannes.Conclusion器官匹配可能是一个更好的设置校正技术比BM光子治疗和IMPT计划。然而，在IMPT的某些射束布置中，由于分次间解剖结构变化，使用OM时剂量分布可能会稍差。因此，选择不太可能受胃肠道气体体积变化影响的射束角度非常重要，尤其是在IMPT计划中。
Purpose To investigate the impact of interfractional anatomical changes and setup correction methods on dose distributions in pancreatic cancer patients under breath-hold conditions.Methods Three intensity-modulated proton therapy (IMPT) plans with different beam arrangements and one volumetric-modulated arc therapy (VMAT) plan prescribing 54 Gy in 30 fractions were created for 10 patients who underwent three additional CT scans performed at an interval of 1-2 weeks. The additional CT sets were rigidly registered to the simulation CT set using both bone-matching (BM) and organ-matching (OM) methods in each patient. Recalculated dose distributions and dose-volume indices on the additional CT sets using either the BM or the OM method were compared with the simulation values.Results Differences in the gross tumor volume D-98% value from the simulation sets ranged from -0.8 to -5.9% on average. In addition, the variations were larger with OM compared with BM for two IMPT plans. Meanwhile, differences in the D-98% value in the region isotropically enlarged by 5 mm from the gross tumor volume were significantly improved with OM on two IMPT plans and the VMAT plan. Among the organs at risk, the dose-volume indices were significantly improved with OM only in the duodenum on all plans.Conclusion Organ-matching may be a better setup correction technique than BM for both photon therapy and IMPT plans. However, in some beam arrangements of IMPT, the dose distribution may be somewhat worse using OM, due to interfractional anatomical variation. Therefore, it is important to choose beam angles that are less likely to be influenced by changes in the gastrointestinal gas volume, especially in IMPT plans.