Varian 23EX加速器固定剂量率旋转调强技术的Portal Dosimetry验证  

Dose verification of constant dose rate-volumetric modulated arc therapy plan based on Varian 23EX accelerator via Portal Dosimetry

作　　者：王杰 邵凯南[2] 陈鹏 曾嵘 姜琦 郑士明 闵旭红 WANG Jie;SHAO Kainan;CHEN Peng;ZENG Rong;JIANG Qi;ZHENG Shiming;MIN Xuhong(Department of Radiation Oncology,Anhui Chest Hospital,Hefei 230022,China;Department of Radiation Physics,Zhejiang CancerHospital,Hangzhou 310022,China)

机构地区：[1]安徽省胸科医院肿瘤放疗科,安徽合肥230022 [2]浙江省肿瘤医院放射物理室,浙江杭州310022

出　　处：《中国医学物理学杂志》2019年第10期1134-1138,共5页Chinese Journal of Medical Physics

基　　金：国家卫生计生委医药卫生科技发展研究中心项目(W2015XR28)

摘　　要：目的:应用Varian公司的Portal Dosimetry系统和ScandiDos公司的Delta4三维半导体阵列对Varian 23EX加速器固定剂量率旋转调强(CDR-VMAT)计划进行验证并对比分析。方法:随机选取10例头颈部肿瘤患者、10例胸部肿瘤患者和10例腹部肿瘤患者,采用Ray Station计划系统在Varian 23EX加速器上设计CDR-VMAT。照射野根据肿瘤部位合理设计,射线能量为6MVX线,每个弧的剂量率和机架转速恒定并由计划系统优化给出。据此分别生成适用23EX自带EPID的Portal Dosimetry验证计划和适用Delta4的验证计划,按照3mmDTA、3%Dose标准分析其Gamma通过率,并进行配对t检验。结果:10例头颈部肿瘤CDR-VMAT计划Portal Dosimetry验证和Delta4验证的Gamma通过率分别为(97.9±1.1)%和(99.9±0.2)%,P<0.05。10例胸部肿瘤CDR-VMAT计划的Gamma通过率分别为(99.5±0.7)%和(99.7±0.4)%,P=0.09。10例腹部肿瘤CDR-VMAT计划的Gamma通过率分别为(99.5±0.3)%和(99.7±0.4)%,P=0.19。结论:CDR-VMAT技术作为Varian23EX加速器一种可选的放射治疗技术能够有效提高机器的计划执行效率,配合Varian Portal Dosimetry系统可以方便地对23EX加速器上的CDR-VMAT计划进行验证。通过与Delta4进行比较,对胸部和腹部肿瘤计划,其Gamma通过率均大于95%且无显著差异,对于头颈部肿瘤计划Gamma通过率有差异,但均满足大于95%的要求。Objective To verify and comparatively analyze the doses of constant dose rate-volumetric modulated arc therapy (CDRVMAT) plan based on Varian 23EX accelerator using Varian Portal Dosimetry system and ScandiDos Delta4 three-dimensional semiconductor array. Methods RayStation treatment planning system was used to design CDR-VMAT plans based on Varian 23EX accelerator for randomly selected 10 head and neck cancer patients, 10 chest cancer patients and 10 abdominal cancer patients. Radiation fields were designed according to tumor location, and 6 MV X ray was adopted. The constant dose rate of each arc and constant gantry speed were optimized by treatment planning system. Every CDR-VMAT plan was used to generate two verification plans, with one for Portal Dosimetry system of electronic portal imaging device of 23EX and the other for Delta4 chamber array detector. Gamma passing rate was analyzed based on the criteria of 3 mm DTAand 3% Dose, and the results were analyzed with paired t test. Results For 10 cases of head and neck cancer, the Gamma passing rates of CDR-VMAT plan verified with Portal Dosimetry system and Delta4 were (97.9±1.1)% and (99.9±0.2)%, respectively (P<0.05). For 10 cases of chest cancer, the Gamma passing rates were (99.5±0.7)%and (99.7±0.4)%, respectively (P=0.09). For 10 cases of abdominal cancer, the Gamma pass rates were (99.5±0.3)% and (99.7±0.4)%, respectively (P=0.19). Conclusion CDR-VMAT as an additional radiotherapy option for Varian 23EX accelerator can effectively improve delivery efficiency. The combination of CDR-VMAT and Varian Portal Dosimetry system can easily achieve the verification of CDR-VMAT plan based on 23EX accelerator. The comparative analysis on Gamma passing rates show that both the Gamma passing rates of CDR-VMAT plans for chest cancer and abdominal cancer are higher than 95%, without statistical differences, while there is difference in Gamma passing rate of CDR-VMAT plans for head and neck cancer, but both the Gamma passing rates are still above 95%, satisfying

关 键 词：加速器 固定剂量率 旋转调强 电子射野影像系统 剂量验证 

分 类 号：R811.1[医药卫生—放射医学] R312[医药卫生—临床医学]