宫颈癌调强放射治疗的临床剂量学研究

Clinical Dosimetry Study of Intensity Modulated Radiotherapy for Cervical Carcinoma

目的在传统的七野均分三维调强放射治疗计划基础上,探究同一布野条件下,适当降低靶区剂量均匀性对正常组织产生的影响。方法随机选取2018年11月至2019年4月在安徽医科大学第一附属医院接受调强放射治疗的Ⅲ、Ⅳ期晚期宫颈癌患者20例,对每例患者的计划靶区(PTV)分别设计常规七野(7F-Plan1)和适当降低靶区剂量均匀性后的新七野(7F-Plan2)两套IMRT计划,所有处方剂量均为50 Gy/25 f,分别对两套计划的靶区均匀性指数(HI)、适形指数(CI)、靶区和正常组织受照量及受照体积等参数进行统计学分析。结果 7F-plan1与7F-plan2相比:在满足肿瘤靶区处方剂量的前提下,7F-plan2中膀胱的Dmean、V40明显低于7F-plan1(P<0.05);7F-plan2中直肠的Dmean、V40明显低于7F-plan1(P<0.05);7F-plan2中脊髓Dmax明显低于7F-plan1(P<0.05);均具有统计学意义。结论在相同布野条件下,适当降低靶区剂量均匀性,在满足肿瘤靶区处方剂量的同时,能更好的保护膀胱、直肠和脊髓等正常组织,为临床治疗提供参考。

Objective In this paper,Based on the traditional 3D IMRT plan,we will explore the effect of appropriately reducing dose uniformity in target area on organs at risk under the same conditions.Methods From November 2018 to April 2019,20 patients with advanced stageⅢandⅣcervical cancer were treated in the first affiliated Hospital of Anhui Medical University.The traditional seven-field(7F-Plan1)and the new seven-field(7F-Plan2)were designed respectively for each patient with the same target(PTV).The prescribe doses is 50 Gy/25 f.Dosimetric evaluation was carried out by calculating the uniformity index(HI),conformal index(CI)and dose volume histogram of PTV and endangering organs respectively.Results Under the premise of ensuring the dose and uniformity of PTV,The Dmean,V40 of bladder and rectum in 7F-plan2 was significantly lower than that in 7F-plan1(P<0.05),and the Dmax of spinal cord in 7F-plan2 was significantly lower than that in 7F-plan1(P<0.05).Conclusion Under the same field conditions,the normal tissues can be better protected on the basis of reducing the dose uniformity of PTV,such as rectum、bladder and spinal cord.