Rectal dose variation during the course of image-guided radiation therapy of prostate cancer
Rectal dose variation during the course of image-guided radiation therapy of prostate cancer
复制标题
DOI：
10.1016/j.radonc.2010.02.023
复制
发表时间：
2010-05-01
影响因子：
5.7
通讯作者：
Ma, C. M. Charlie
中科院分区：
文献类型：
--
作者：
Chen, Lili;Paskalev, Kamen;Ma, C. M. Charlie
背景与目的：探讨影像引导下前列腺癌调强放疗（IMRT）治疗过程中直肠剂量的变化。材料与方法：回顾性研究20例前列腺癌患者。所有患者均接受了IMRT治疗。每个病人。将MR和CT图像进行融合，对目标和关键结构进行描绘。对模拟CT图像进行IMRT治疗计划。在治疗过程中，使用CT-on-rails系统纠正了分数间运动。直肠的轮廓在最初的治疗计划和随后的日常CT图像上都是由同一研究者绘制的。在原始治疗方案的基础上，使用叶片序列/MUs重新计算这些每日CT图像上的剂量分布，并相对于模拟CT图像进行等中心移位。根据我们的临床接受标准，将随后每日CT的直肠剂量与模拟CT上计划的原始剂量进行比较。结果：基于20例患者139台每日CT， 28%的后续治疗剂量分布不符合我们的标准V-40 < 35%。27%不符合V-65 < 17%的标准。对于某些患者，分数间直肠容积变化是显著的。结论：由于直肠容积分数间差异较大，以空直肠为基础进行前列腺IMRT计划，对空直肠患者进行治疗更为有利。超过70%的实际治疗显示直肠剂量优于我们的临床接受标准。很大一部分（27%）的实际治疗将受益于基于日常CT图像的自适应图像引导放疗。2010爱思唯尔爱尔兰有限公司版权所有。放射治疗与肿瘤学95 (2010)198-202
Background and purpose: To investigate the change in rectal dose during the treatment course for intensity-modulated radiotherapy (IMRT) of prostate cancer with image-guidance.Materials and methods: Twenty prostate cancer patients were recruited for this retrospective study. All patients have been treated with IMRT. For each patient. MR and CT images were fused for target and critical structure delineation. IMRT treatment planning was performed on the simulation CT images. Inter-fractional motion during the course of treatment was corrected using a CT-on-rails system. The rectum was outlined on both the original treatment plan and the subsequent daily CT images from the CT-on-rails by the same investigator. Dose distributions on these daily CT images were recalculated with the isocenter shifts relative to the simulation CT images using the leaf sequences/MUs based on the original treatment plan. The rectal doses from the subsequent daily CTs were compared with the original doses planned on the simulation CT using our clinical acceptance criteria.Results: Based on 20 patients with 139 daily CT sets, 28% of the subsequent treatment dose distributions did not meet our criterion of V-40 < 35%. and 27% did not meet our criterion of V-65 < 17%. The inter-fractional rectal volume variation is significant for some patients.Conclusions: Due to the large inter-fractional variation of the rectal volume, it is more favorable to plan prostate IMRT based on an empty rectum and deliver treatment to patients with an empty rectum. Over 70% of actual treatments showed better rectal doses than our clinical acceptance criteria. A significant fraction (27%) of the actual treatments would benefit from adaptive image-guided radiotherapy based on daily CT images. (C) 2010 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 95 (2010) 198-202