Open AccessIndividual volume‐based 3D gamma indices for pretreatment VMAT QA
Author(s) -
Yi Jinling,
Han Ce,
Zheng Xiaomin,
Zhou Yongqiang,
Deng Zhenxiang,
Xie Congying,
Jin Xiance,
Jin Fu
Publication year - 2017
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12062
Subject(s) - nuclear medicine , volume (thermodynamics) , dose volume histogram , radiation therapy , mathematics , histogram , correlation , radiation treatment planning , medicine , statistics , computer science , radiology , artificial intelligence , physics , geometry , quantum mechanics , image (mathematics)
Although gamma analysis is still a widely accepted quantitative tool to analyze and report patient‐specific QA for intensity‐modulated radiotherapy ( IMRT ) and volumetric‐modulated arc therapy ( VMAT ), the correlation between the 2D percentage gamma passing rate (% GP ), and the clinical dosimetric difference for IMRT and VMAT has been questioned. The purpose of this study was to investigate the feasibility of individual volume‐based 3D gamma indices for pretreatment VMAT QA . Percentage dosimetric errors (% DE ) of dose‐volume histogram metrics (includes target volumes and organ at risks) between the treatment planning system and QA ‐reconstructed dose distribution, % GPs for individual volume and global gamma indices, as well their correlations and sensitivities were investigated for one‐ and two‐arc VMAT plans. The % GP s of individual volumes had a higher percent of correlation with individual 15 % DE metrics compared with global % GP s. For two‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume % GP s were correlated with 9, 12, and 9 out of 15 % DE metrics, while global % GP s were correlated with only 2 out of 15 % DE metrics, respectively. For one‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume % GP s were correlated with 18, 16, and 13 out of 23 % DE metrics, and global % GP s were correlated with 19, 12, and 1 out 23 % DE metrics, respectively. The area under curves ( AUC ) of individual volume % GP s were higher than those of global % GP s for two‐arc VMAT plans, but with mixed results for one‐arc VMAT plans. In a conclusion, the idea of individual volume % GP was created and investigated to better serve for VMAT QA and individual volume‐based % GP had a higher percent of correlation with DVH 15 % DE metrics compared with global % GP for both one‐ and two‐arc VMAT plans.