摘要
Abstract
Objective To investigate how pitch choice affects positioning errors during megavoltage computed tomography(MVCT)scanning using the Onrad system,a tomography radial radiotherapy system,for cervical cancer treatment.Methods A total of 16 cervical cancer patients who underwent Onrad system treatment in Department of Radiotherapy Shenzhen People's Hospital from October 2023 to January 2024 were chosen.The patients were split into two groups:Normal group(n=8)and Coarse group(n=8)based on the pitch utilized during MVCT scanning.Every day,an MVCT scan was conducted.By comparing the results with the positioning CT picture,the XYZ three-dimensional translation error and rolling error around the Y axis(Roll)were determined.Both the error data and the scanning time were tracked down and examined.Results In the Normal group and the Coarse group,200 sets of displacement error data in total were collected.The three-dimensional translation errors of Normal group were X=1.80±1.28 mm,Y=2.22±1.43 mm,Z=1.78±1.30 mm,and the rolling error was Roll=0.32±0.41°.The 3D translation errors of Coarse group were X=1.98±1.18 mm,Y=2.38±1.34 mm,Z=1.96±1.27 mm,and rolling error was Roll=0.31±0.47°.For both the rolling error Roll(P=0.71)and the translation errors X,Y,Z(P=0.15,0.23,0.17),there was no discernible difference in the positioning errors between the two groups.When the pitch was set to Normal,the scanning time was substantially greater than when the pitch was set to Coarse in terms of scanning efficiency(253.4±9.7 vs 173.3±7.9 s,P<0.001).Conclusion For position calibration,MVCT images are scanned with Normal and Coarse pitch when the Onrad system is utilized for cervical cancer radiation therapy.The XYZ 3D translation errors and rolling error do not differ.Nevertheless,Coarse pitch selection increased scanning efficiency.There fore,Coarse pitch was advised.关键词
MVCT/Onrad系统/摆位误差/宫颈癌Key words
MVCT/onrad system/positioning error/cervical cancer
