IMPACT OF INTRAFRACTIONAL BOWEL GAS MOVEMENT ON CARBON ION BEAM DOSE DISTRIBUTION IN PANCREATIC RADIOTHERAPY
IMPACT OF INTRAFRACTIONAL BOWEL GAS MOVEMENT ON CARBON ION BEAM DOSE DISTRIBUTION IN PANCREATIC RADIOTHERAPY
复制标题
DOI：
10.1016/j.ijrobp.2008.10.055
复制
发表时间：
2009-03-15
影响因子：
7
通讯作者：
Kamada, Tadashi
中科院分区：
文献类型：
--
作者：
Kumagai, Motoki;Hara, Ryusuke;Kamada, Tadashi
目的：探讨胰腺放射治疗中碳离子束因肠气运动引起的剂量变化。方法与材料：对10例住院胰腺癌患者在屏气条件下行诊断性对比增强动态螺旋CT检查，包括动脉期、静脉期和延迟期多期动态CT检查。动-静脉期和动脉-延迟期间隔分别为35 s和145 s。一个补偿丸被设计来覆盖在动脉期获得的目标。通过将bolus应用于其他两个阶段的CT数据集来计算碳离子剂量分布。结果：由于肠道气体运动导致的光束过调/过调降低了剂量对临床靶体积的构象。145 s时，临床靶体积D95从处方剂量的98.2%（范围98.0 ~ 99.1%）降至94.7%（范围88.0 ~ 99.0%）。正常组织的过量剂量因组织而异，例如为12.2 GyE/13.1。脐带GyE（0秒/145秒）和十二指肠GyE (38.8 GyE/39.8 GyE（0秒/145秒）。光束过冲/欠冲的程度从前方向和左方向特别加剧。结论：肠气体运动引起放射治疗过程中靶的剂量变化。肠道气体运动的影响随光束角度的不同而不同，对前后梁和左右梁的影响最大。(C) 2009爱思唯尔公司
Purpose: To assess carbon ion beam dose variation due to bowel gas movement in pancreatic radiotherapy.Methods and Materials: Ten pancreatic cancer inpatients were subject to diagnostic contrast-enhanced dynamic helical CT examination under breath-holding conditions, which included multiple-phase dynamic CT with arterial, venous, and delayed phases. The arterial-venous phase and arterial-delayed phase intervals were 35 and 145 s, respectively. A compensating bolus was designed to cover the target obtained at the arterial phase. Carbon ion dose distribution was calculated by applying the bolus to the CT data sets at the other two phases.Results: Dose conformation to the clinical target volume was degraded by beam overshoot/undershoot due to bowel gas movement. The D95 for clinical target volume was degraded from 98.2% (range, 98.0-99.1%) of the prescribed dose to 94.7% (range, 88.0-99.0%) at 145 s. Excessive dosing to normal tissues varied among tissues and was, for example, 12.2 GyE/13.1. GyE (0 s/145 s) for the cord and 38.8 GyE/39.8 GyE (0 s/145 s) for the duodenum. The magnitude of beam overshoot/undershoot was particularly exacerbated from the anterior and left directions.Conclusions: Bowel gas movement causes dosimetric variation to the target during treatment for radiotherapy. The effect of bowel gas movement varies with beam angle, with greatest influence on the anterior-posterior and left-right beams. (C) 2009 Elsevier Inc.