Optical surface monitoring-based real-time 3D in vivo dose verification for patients with left breast cancer undergoing deep inspiration breath-hold radiotherapy
Objective To perform optical surface monitoring-based three-dimensional(3D)in vivo dose verification for patients with left breast cancer undergoing deep inspiration breath-hold surface-guided radiation therapy(DIBH-SGRT)and to investigate the dosimetric differences in the target volumes and related factors affecting γ pass rates.Methods Totally 20 patients with left breast cancer who received DIBH-SGRT at the Department of Radiation Oncology,Women's Hospital,School of Medicine,Zhejiang University were selected.The optical surface monitoring-based intrafractional displacement deviations of the patients during DIBH were recorded.Meanwhile,electronic portal imaging device(EPID)-based in vivo dosimetry(EIVD)verification was performed for patients during the DIBH-SGRT,and γ pass rates were measured with the criteria of 2 mm/2％,3 mm/3％,and 3 mm/5％.The dosimetric differences between planning target volumes(PTVs)and organs at risk(OARs)were analyzed based on dose-volume histograms(DVHs).Furthermore,Pearson correlation analysis was employed to determine the correlation of three γ pass rates with dosimetric differences and displacement deviations.Results The average pass rates with the criteria of 2 mm/2％,3 mm/3％,and 3 mm/5％were determined at 73.43％,86.00％,and 92.96％,respectively,and the average deviations between EIVD measured doses and planned doses in PTV_TB and PTV Dmean were proved to be 0.23％and 0.59％,respectively(P＞0.05).Pearson analysis revealed that the γ pass rates exhibited a weak correlation with dosimetric differences in PTVs(R＜0.7)but strong correlations with intrafractional displacement deviations in Lat and Vert directions during DIBH(R＞0.7).Conclusions EIVD verification can ensure the high accuracy of dose delivery in PTVs during DIBH-SGRT for left breast cancer.Additionally,the EIVD verification system has the potential to detect displacement deviations during breath holding.
Left breast cancerDeep inspiration breath-hold surface guided radiation therapy3D in vivo dose verificationγ pass rate
万方数据
维普
