直肠癌调强放疗计划中六维随机摆位误差的剂量学影响研究  

The dosimetric effect of random six-dimensional setup error in intensity-modulated radiotherapy planning for rectal cancer

作　　者：郑佳俊 游鸿强 徐庚[1] 翟振宇[1] 何侠[1] 孙丽[1] Zheng Jiajun;You Hongqiang;Xu Geng;Zhai Zhenyu;He Xia;Sun Li(Department of Radiation Oncology,Jiangsu Cancer Hospital,Jiangsu Institute of Cancer Research,Affiliated Cancer Hospital of Nanjing Medical University,Nanjing 210009,China;School of Biomedical Engineering and Informatics,Nanjing Medical University,Nanjing 211103,China;Department of Radiation Oncology,Affliated Cancer Hospital of Fuzhou Medical University,Fujian Cancer Hospital,Fuzhou 350014,China;School of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China)

机构地区：[1]江苏省肿瘤医院江苏省肿瘤防治研究所南京医科大学附属肿瘤医院放疗科,南京210009 [2]南京医科大学生物医学工程与信息学院,南京211103 [3]福建医科大学肿瘤临床医学院福建省肿瘤医院放疗中心,福州350014 [4]南京航空航天大学材料科学与技术学院,南京211106

出　　处：《中华放射医学与防护杂志》2023年第11期881-887,共7页Chinese Journal of Radiological Medicine and Protection

基　　金：国家重点研发计划项目(2022YFC2404605)。

摘　　要：目的设计一种软件将随机六维摆位误差引入到直肠癌调强放疗(IMRT)计划中,并评估其剂量学影响。方法随机选取21例直肠癌IMRT计划作为参考计划(单次剂量2 Gy,共50 Gy;PTV为CTV均匀外扩5 mm)。对参考计划的每个分次,通过调整射野几何参数的方法引入随机生成的六维摆位误差,并重新完成剂量计算。再将各分次剂量累加后得到存在摆位误差情况下的总剂量分布。基于美国瓦里安Eclipse脚本应用程序接口(ESAPI)开发能够自动完成上述流程的治疗模拟软件,将服从两种预设分布[分布1:平移误差服从N(0,4^(2)),旋转误差服从N(0,2^(2));分布2:平移误差服从N(0,2^(2)),旋转误差服从N(0,1^(2))]的六维摆位误差引入参考计划,并评估剂量学影响。结果参考计划、误差分布1和误差分布2情况下,CTV的D_(min)分别为(49.4±0.41)、(47.56±0.76)和(49.17±0.64)Gy;CTV的D 98%分别为(50.23±0.07)、(49.98±0.10)和(50.27±0.09)Gy;主体靶区(靶区除去边缘后的内核部分)D_(98%)为(50.25±0.08)、(50.42±0.13)和(50.33±0.10)Gy;边缘靶区D_(98%)为(50.22±0.10)、(49.88±0.11)和(50.26±0.10)G_(y)。另外,相比参考计划,误差分布1和2的情况下,膀胱和股骨头平均受量的变化差异均无统计学意义(P>0.05),剂量分布的适形指数虽有微弱降低,但临床意义有限。结论本方法及据此开发的治疗模拟软件可以根据需要将服从不同分布的六维摆位误差引入到直肠癌IMRT计划中,并给出总体剂量学变化情况。ObjectiveTo design a method to introduce random six-dimensional setup error(6D-SE)into the intensity-modulated radiotherapy(IMRT)planning for rectal cancer and evaluate its dosimetric effect.MethodsA total of 21 IMRT plans for patients with rectal cancer were randomly selected as reference plans[2 Gy per fraction for a total of 50 Gy;a 5 mm uniform margin around the clinical target volume(CTV)was taken as the planning target volume(PTV)].For each fraction of the reference plan,a randomly generated 6D-SE was introduced by adjusting the geometrical parameters of the radiation field,and the dose was recalculated.The overall dose distribution with 6D-SE was obtained by adding up the dose of each fraction.A treatment simulation program that could complete the above workflow was developed using the Varian Eclipse scripting API(ESAPI).6D-SEs that obey two preset distributions[distribution 1:translational error obey N(0,4^(2)),and rotational error obey N(0,2^(2));distribution 2:translational error obey N(0,2^(2)),and rotational error obey N(0,1^(2))]were introduced into the reference plans,and the dosimetric effects were assessed.Results When the reference plans,error distribution 1,and error distribution 2 were applied,the D_(min) values of the CTV were(49.4±0.41),(47.56±0.76),and(49.17±0.64)Gy,respectively;the D_(98%)values of the CTV were(50.23±0.07),(49.98±0.10),and(50.27±0.09)Gy,respectively;the D_(98%)values of the primary target area(the kernel part of the target area,excluding the margins)were(50.25±0.08),(50.4^(2)±0.13),and(50.33±0.10)Gy,respectively;the D_(98%)values of the marginal area were(50.2^(2)±0.10),(49.88±0.11),and(50.26±0.10)Gy,respectively.In addition,compared with the result of the reference plans,the result of errors 1 and 2 showed no significant changes in the mean dose of the bladder and femoral heads(P>0.05),despite slight decreases in the conformity index of the dose distribution with limited clinical significance.ConclusionThe proposed method and the treatment simulation program de

关 键 词：直肠癌 调强放疗 六维摆位误差 ESAPI 剂量学 

分 类 号：R735.37[医药卫生—肿瘤] R730.55[医药卫生—临床医学]