摘要目的 比较分析局部晚期宫颈癌腔内联合组织间插植近距离治疗计划3种优化方法的剂量学差异.方法 回顾性选取局部晚期宫颈癌患者20例,对每例患者根据不同优化方法,分别制定3种计划,分别为手动计划组,基于图形优化;逆向1计划组,基于模拟退火优化算法;逆向2计划组,在逆向1组基础上增加了靶区(CTV)最大剂量限定.比较计划中CTV的体积剂量参数V200、V150、V100、D100、D90、均匀性指数(HI),以及直肠、膀胱、乙状结肠的剂量参数D0.1cm3、D1cm3、D2cm3.结果 CTV方面,手动组和2个逆向组的D100参数差异无统计学意义(P＞0.05),但2个逆向组的V200、V150、V100、HI参数明显优于手动组(t=-3.422～9.910,P＜0.05).逆向1组的V100和D100优于逆向2组(t=7.238、5.032,P＜0.05).危及器官(OARs)方面,与手动组相比,2个逆向组中直肠、膀胱、乙状结肠的D0.1 cm3、D1 cm3和D2 cm3明显降低(t=2.235 ～5.819,P ＜0.05).结论 对于局部晚期宫颈癌腔内联合组织间插植技术,基于3组优化方法的计划均能满足临床需求,且使用逆向优化方法保证了靶区剂量覆盖,同时减少直肠、膀胱、乙状结肠的最大受量.

abstractsObjective To compare and analyze the dosimetric discrepancy of combind intracavitary/interstitial brachytherapy using three different kinds of optimization method in locally advanced cervical cancer.Methods Totally 20 cases of locally advanced cervical cancer were selected and divided into three groups according to different optimization method which include manual optimization group (MO) based on graphical optimization,inverse planning simulated annealing (IPSA 1)based on simulated annealing optimization algorithm,IPSA 2 based on IPSA 1 with limitation on maximum dose of target.The dose volume histogram parameters of the targets (V200,V150,V100,D100,D90,HI) and the OARs(D0.1 cm3,D1 cm3 and D2 cm3) were analyzed.Results For CTV,compared with MO,there was no significantly statistical difference in D100between IPSA 1 and IPSA 2(P ＞ 0.05).However,V200,V150,V100 and HI for ISPA1 were better than for ISPA2 (t =-3.422-9.910,P ＜ 0.05).In addition,V100 and D100 in ISPA1 were better than in ISPA2 (t =7.238,5.032,P ＜0.05).For OARs,D0.1 cm3,D1 cm3 and D2 cm3 in rectum,bladder,sigmoid colon of both ISPA 1 and ISPA 2 were dramatically lower than those of MO (t =2.235 5.819,P ＜ 0.05),without significantly statistical difference found between ISPA1 and ISPA2.Conclusions For combined intracavitary/interstitial brachytherapy in locally advanced cervical cancer,all treatment plans based on three different kinds of optimization methods can meet the clinical need.Moreover,inverse optimization can ensure dose coverage over target and reduce maximum dose of rectum,bladder and sigmoid colon.