宫颈癌放疗计划中小肠3种勾画方法比较

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45 Gy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D_max、D_mean、CI、HI和小肠肠管D_max、D_mean、V₅—V₄₅差异并配对t检验。结果 BL与BB计划相比,PTV在D_max、CI、HI上相近(P=0.171、0.076、0.192),D_mean不同(P=0.017);小肠肠管D_max不同(P=0.038),V₅—V₄₅相近(P=0.315~0.855)。BL与PS计划下相比,PTV的D_max、D_mean、CI、HI均不同(P=0.033、0.044、0.046、0.041),小肠肠管D_max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D_max控制方面,勾画肠袋较腹膜腔似乎更好一些。

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

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),D of PTV and Dmax of bowel loops had difference (P=0.017,0.038).Comparison between BL and PS plan,Dmax,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≤20％.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.