Establishment and evaluation of a daily quality assurance tool for LINAC based on electronic portal image device
10.3760/cma.j.issn.0254-5098.2019.04.007
- VernacularTitle:基于电子射野影像系统建立医用直线加速器晨检工具的临床测试
- Author:
Yangguang MA
1
;
Tao WANG
;
Shuaipeng LIU
;
Hongwei LI
;
Chuanxian JI
;
Jia HUO
;
Xuemin WANG
;
Rui NIU
;
Yuexin GUO
Author Information
1. 郑州大学第一附属医院放射治疗部 450052
- Keywords:
Electron portal image device;
Linac;
Daily quality assurance;
Quality control
- From:
Chinese Journal of Radiological Medicine and Protection
2019;39(4):280-284
- CountryChina
- Language:Chinese
-
Abstract:
Objective To establish and evaluate a morning check system for linac based on electronic portal image device (EPID).Methods Delivered fluence maps of open and wedge fields at 10 cm×10 cm field size of Synergy Linac were measured by EPID.Figure features from these two images were extracted with matlab codes and analyzed to realize a quick morning check.The repeatability of dose response and mechanical setup,relationship between gray value and machine unit (MU),accuracy of output and field size test were investigated with both EPID and DailyQA3.The status of Synergy linac was monitored both by DailyQA3 and EPID for two months.Results EPID was able to test the linac consistently with a testing error of 0.50 mm,1.00 mm for field size and center,respectively.Both of the test accuracy for flatness and symmetry was 0.17％.The mechanical accuracy test and dosimetric repeatability test were also consistent.The dose response of EPID was linearly related to the linac output (R2＞0.999).EPID was highly sensitive to the change of output and radiation field size.The measurement deviations between EPID and DailyQA3 were consistent and within clinical acceptable tolerance.Conclusions EPID showed great accuracy and stability on monitoring the performance of linac.The established daily check tool based-on EPID is accurate and reliable for clinical usage.
