宫颈癌放疗计划中小肠3种勾画方法比较

The comparison of three bowel delineation strategies in the radiation therapy of cervical cancer

目的基于3种方法勾画小肠并分别制定放疗计划，评估小肠肠管受照剂量体积差异及3种勾画方法的可行性。方法选择宫颈癌初期患者12例，处方剂量45Gy分25次，分别以勾画小肠肠管法（BL）、肠袋法（BB）和勾画整个腹膜腔法（PS）为目标函数制定放疗计划，评估PTV的Dmax、Dmean、CI、HI和小肠肠管Dmax、Dmean、V5-V45差异并配对t检验。结果BL与BB计划相比，PTV在Dmax、CI、HI上相近（P=0．171、0．076、0．192），Dmean不同（P=0．017）；小肠肠管Dmax不同（P=0．038），V5-V45相近（P=0．315～0．855）。BL与PS计划下相比，PTV的Dmax、Dmean、CI、HI均不同（P=0．033、0．044、0．046、0．041），小肠肠管Dmax不同（P=0．013），V5-V45相近（P=0．416—0．977）。从计划结果看要想使小肠肠管V40≤15％，肠袋和腹膜腔V40应≤20％。结论采用3种勾画方法制定的放疗计划都能使小肠肠管达到相似剂量体积，从PTV的CI、HI及小肠肠管Dmax控制方面，勾画肠袋较腹膜腔似乎更好一些。

Objective To study three contouring approaches of the bowel and evaluate the bowel dose volume with cervical cancer patient. Methods Twelve patients were selected, prescribed dose 45 Gy/ 25f. For each patient we contoured the bowel according to three different definitions：bowel loops, bowel bag and peritoneal space. Then we generated three rival plans each considering a different bowel definition and to evaluate dose differences of the HI, CI of PTV and D D V5-V45 of bowel loops with paired t-test. Results Comparison between BL and BB plan, Dmax, HI and CI of PTV, V5-V45 of bowel loops were not significantly different （P=0. 171,0. 076,0. 192,P= 0. 315-0. 855）, Dmean of PTV and Dmax of bowel loops had difference （P=0. 017,0. 038） .Comparison between BL and PS plan,D D HI and CI of PTV and Dmax of bowel loops had differences （ P= 0. 033,0. 044,0. 046,0. 041,0. 013 ） , V5-V45 of bowel loops were not significantly different （ P= 0. 416-0. 977 ）. If the bowel loops V40 ≤ 15%, and bowel bag and peritoneal space V40≤420%. Conclusions All definitions provided a very similar dose volume of bowel loops. Taking into account HI and CI of PTV and max dose of bowel loops, BB seems better than PS.