基于先验知识的宫颈癌调强计划自动优化的可行性研究

Feasibility of knowledge-based IMRT planning automatic optimization for cervical cancer

目的通过比较宫颈癌经验引导调强(knowledge-based intensity-modulated radiotherapy,K-IMRT)与常规调强(conventional intensity-modulated radiotherapy,C-IMRT)在计划靶区(planning target volume,PTV)和危及器官(organ at risk,OAR)的剂量学差异,探讨基于先验知识的宫颈癌调强计划自动优化的可行性。方法选取山东省肿瘤医院2014-05-01-2014-09-01宫颈癌术后患者10例,进行CT模拟定位、靶区和危及器官的勾画,用Eclipse 13.0治疗计划系统基于同一CT图像进行K-IMRT和C-IMRT调强计划设计。在95%体积的PTV达到处方剂量的条件下,比较两种调强计划的剂量体积直方图(dose volume histogram,DVH),分析靶区均匀性指数(homogeneity index,HI)、适形度指数(conformity index,CI)、OAR受照剂量和计划时间。结果 K-IMRT计划与C-IMRT计划在靶区受照剂量、HI和CI差异均无统计学意义,P>0.05。膀胱V30、左股骨头V40、右股骨头V20、V30和D50K-IMRT计划明显优于C-IMRT计划,差异有统计学意义,P<0.05。膀胱V20、V30和D50,直肠V20、V30和V50及左右股骨头受照剂量均值都低于C-IMRT计划。计划时间K-IMRT明显缩短。结论宫颈癌术后基于先验知识的调强计划自动优化结果可以达到与C-IMRT计划相似的靶区剂量分布,能够降低危及器官的受照受量,在计划优化应用中是可行的。

OBJECTIVE To discuss the feasibility of knowledge-based IMRT planning automatic optimization for cervical cancer by comparing the dosimetric differences of the planning target volume （PTV） and the organ at risk （OAR） for postoperative patients with cervical cancer on knowledge-based radiation therapy（K-IMRT） and conventional intensity- modulated radiotherapy（C-IMRT）. METHODS From May 1,2014 to September 1,2014,ten postoperative patients with cervical cancer were chosen and their CT scan, PTV and OAR contouring were obtained. K-IMRT plan and C-IMRT plan were performed for each CT image respectively with Eclipse 13, 0 system. Under the condition of 95%~ volume of PTV of prescription dose, DVH of two treatment plans, conformal dose of target volume and OARs, HI,CI and planning time were compared. RESULTS The K-IMRT plan compared with C-IMRT planning, dose of PTV, HI and CI had no signifi- cant differences（P〉0.05）. There were significant differences in V20, V30, D50 of bladder, V20 , V30, V50 of rectum and fe- mur（P〈0.05）. CONCLUSION K-IMRT plans, keeping with C-IMRT plans in dose distribution of the target reduces the dose of OARs and are feasible in the plan optimization application.