A study of the iso-center point coincidence between accelerator and radiotherapy planning system
10.3760/cma.j.issn.1004-4221.2016.06.018
- VernacularTitle:利用验证计划数据分析不同机器与计划中心点重合性
- Author:
Xiaoyang SUN
;
Bo YANG
;
Haowen PANG
;
Guangpeng ZHANG
;
Jing ZHANG
;
Renjin CHEN
;
Jingbo WU
- Publication Type:Journal Article
- Keywords:
Radiotherapy plan verification;
Gamma pass rate;
Center point;
Accelerator
- From:
Chinese Journal of Radiation Oncology
2016;25(6):625-627
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the iso-center point coincidence of two accelerators with treatment planning system (TPS) based on γ passing rates of intensity-modulated radiotherapy (IMRT) plan verification.Methods Twenty-one IMRT plans were verified by Varian accelerator and twenty by Elekta accelerator with a gamma criterion of 3 mm/3％.The passing rates were measured when the iso-center point of TPS had-2,-1,0,1,and 2 mm shift in the x or y direction.A binomial curve of γwas fit to figure out the values of the two accelerators on the x and y axes when γ value reached the maximum.The γ pass rate difference was analysed by x2 test.Results The mean values of γ-2,γ-1,γ0,γ1,and γ2 in the x direction were (92.56±3.27) ％,(96.53± 1.82) ％,(96.13± 1.41) ％,(90.14± 2.87) ％,and (82.28± 4.69) ％ for Varian accelerator,and (94.82± 2.04) ％,(97.05± 2.02) ％,(98.38± 1.33) ％,(97.96± 1.44) ％,and (94.49±2.34)％ for Elekta accelerator.There was no significant difference in the mean value of γ0between the two accelerators (P=0.332).When γvalue reached the maximum,the values on the x and y axes were0.65 and-0.30 mm for Varian accelerator and 0.01 and 0.30 mm for Elekta accelerator,respectively.Conclusions In the same TPS,different accelerators have different degrees of coincidence of the actual field center point with the iso-center point of TPS,to which more attention should be paid in clinical practice.
