Abstract Objective To investigate the factors of effecting with γ index analysis of delivery for helical tomotherapy (HT). Methods Measuring γ index with the ArcCheck device for introduced errors in HT. The errors include setup errors in three-dimensional, the gantry angle error, calculating the dose in the phantom, low dose rate. All the results were compared with the 3%/3 mm and 2%/2 mm criteria. The effect of the accuracy in the application of kilovoltage computed tomography (KVCT) and mega-voltage computed tomography (MVCT) images in HT was also analyzed. Paired-t test method was used for difference compared. Results When the errors were introduced to the HT, theγ passing rate of left-right, superior-inferior, anterior-posterior direction dropped 2.7%, 7.2%, 3.6% under the 3%/3 mm criteria (P=0.002,0.022,0.007), with 4.6%,15.7%,7.6% under the 2%/2 mm criteria (P=0.001,0.003,0.002) respectively. There was no statistical significance for theγ passing between scanning the ArcCheck phantom with the KVCT and MVCT under the 3%/3 mm and 2%/2 mm criteria (98.6% vs 98.7%,P=0.859 and 92.7% vs 92.8%,P=0.984). Conclusions The errors of the setup position and machine paraments can lead to the dose delivery errors in HT, the quality accurance of machine and plan should be enhanced to minimize the dose errors. The results also showed that there is no difference of KVCT and MVCT image on the delivery of HT.
Yue Qi,Duan Jimei,Wang Zhiwei et al. The research on the factors of effecting with γ passing rate of delivery quality assurance for helical tomotherapy[J]. Chinese Journal of Radiation Oncology, 2014, 23(3): 269-271.
Yue Qi,Duan Jimei,Wang Zhiwei et al. The research on the factors of effecting with γ passing rate of delivery quality assurance for helical tomotherapy[J]. Chinese Journal of Radiation Oncology, 2014, 23(3): 269-271.
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