Zhang Haiqin, Wang Renben, Yan Hongjiang, Zhao Wei, Feng Rui, Jiang Shumei, Yu Jinming
Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
Asian Pac J Cancer Prev. 2011;12(11):2969-72.
A prospective study was undertaken to reduce bladder volume variation and the irradiated small bowel injury by irrigating the bladder during postoperative pelvic IMRT in rectal cancer patients.
12 consecutive patients underwent three sets of computed tomography scans during the treatment course: Group I, a distended (not empty) bladder before the radiation course; Group II, a distended bladder at the end of the fourth week; Group III, an irrigated bladder at the end of the fourth week. A seven-field coplanar intensity- modulated radiotherapy plan of 50.4 Gy was made to the clinical target volume. The total volume of regions of interest and volume within every isodose level, their maximum dose and mean dose were analysed.
Compared with group I, the median reduction of bladder volume was 147.7 cm3 (24.3%), and the median increment of small bowel was 122.4 cm3 in group II. The volume of small bowel within every isodose level was increased (P<0.05). Statistical analysis showed a correlation between the volume change of bladder and small bowel. The mean radiation dose (Dmean) of small bowel and bladder was increased in group II compared to groups I and III (P<0.05).
Bladder volume declines significantly during the course of radiotherapy, leading to an increment in irradiated small bowel volume. Bladder irrigation is a feasible method to guarantee a consistent bladder volume and reduce small bowel radiation exposure.
进行一项前瞻性研究，通过在直肠癌患者术后盆腔调强放疗（IMRT）期间对膀胱进行冲洗，以减少膀胱体积变化和小肠受照损伤。
12例连续患者在治疗过程中接受了三组计算机断层扫描：第一组，放疗疗程开始前膀胱充盈（非排空）；第二组，第四周结束时膀胱充盈；第三组，第四周结束时膀胱冲洗。对临床靶体积制定了50.4 Gy的七野共面调强放疗计划。分析感兴趣区域的总体积和每个等剂量水平内的体积、其最大剂量和平均剂量。
与第一组相比，第二组膀胱体积中位数减少147.7 cm³（24.3%），小肠体积中位数增加122.4 cm³。每个等剂量水平内的小肠体积均增加（P<0.05）。统计分析显示膀胱和小肠的体积变化之间存在相关性。与第一组和第三组相比，第二组小肠和膀胱的平均辐射剂量（Dmean）增加（P<0．０５）。
放疗过程中膀胱体积显著下降，导致受照小肠体积增加。膀胱冲洗是保证膀胱体积一致并减少小肠辐射暴露的一种可行方法。
