Preliminary study of physical model test and clinical application based on EPID-based in-vivo dose verification system
10.3760/cma.j.cn113030-20200721-00372
- VernacularTitle:基于EPID在体三维剂量验证系统的物理模型测试及初步临床探索
- Author:
Ronghu MAO
1
;
Wei GUO
;
Bing LI
;
Yong ZHANG
;
Qingjie WANG
;
Xiuyan CHENG
;
Hong GE
;
Hongchang LEI
Author Information
1. 郑州大学附属肿瘤医院 河南省肿瘤医院放疗科 450008
- Keywords:
Electronic portal imaging device;
In-vivo dose verification;
γpassing rate
- From:
Chinese Journal of Radiation Oncology
2021;30(10):1065-1070
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To validate the accuracy of physical model of in-vivo 3D dose verification based on electronic portal imaging device (EPID) using the phantom and preliminarily analyze the clinical application.Methods:Two phantoms (uniform and non-uniform phantoms) were involved in this study. The system of in-vivo 3D dose verification based on EPID was employed to acquire the images of square fields (SF) and combined fields of intensity-modulated radiotherapy (CFIMRT). The physical model of different media was constructed using the system. The factor of γ passing rate under different dose/distance criteria was statistically compared. For clinical cases, the dose-volume histograms were adopted to analyze the dose distribution of target volume and organs at risk (OARs).Results:For the SF in the uniform phantom, the average γ passing rate (3%/3 mm) was (97.49±1.11)%, and (94.06±5.11)% for the SF in the non-uniform phantom ( P>0.05). No statistical significance was noted in IMRT using different delivery methods (all P>0.05). For clinical cases, the average γ passing rate (3%/2 mm) was (97.96±1.84)% in the pre-treatment dose verification, and (90.51±6.96)%(3%/3 mm) for the in-vivo 3D dose verification. For clinical cases, significant dose deviation was observed in OARs with small size and large volume changes. Conclusion:The in-vivo 3D dose verification model based on EPID can be effectively applied in inter-fraction dose verification, providing technical support for adaptive radiotherapy in clinical practice.
