医科达Precise医用直线加速器系统误差的分布特征

Distribution Characteristics of Systematic Errors of Elekta Precise Linac

目的分析医科达Precise医用直线加速器系统误差的分布特征。方法读取医科达Precise医用直线加速器的服务器PreciseNet的日志文件,提取加速器的运行数据,计算系统误差,分析系统误差的分布特征及其与臂架角度的关系。结果通过历史数据对比发现,臂架角度、小机头角度、跳数的系统误差均值在0值附近,无明显分布特征;X1、X2钨门和Y1、Y2钨门及X1、X2多叶光栅的系统误差分别为0.30、0.22、0.50 mm,且偏差方向相反;X1、X2钨门的系统误差随臂架角度呈正弦三角函数变化,多叶光栅的系统误差随臂架角度呈正态分布。结论医科达Precise医用直线加速器的系统误差均在允许范围内,X1、X2钨门的系统误差随臂架角度呈正弦变化,多叶光栅的系统误差则服从正态分布,射野内、外多叶光栅的系统误差无明显差异,跳数几乎没有偏差,臂架角度、小机头角度及Y1、Y2钨门的系统误差无明显分布规律。

Objective The distribution characteristics of systematic errors of Elekta Precise linac were analyzed.Methods The log files were read from PreciseNet server of Elekta Precise linac.The operating data of the linac was extracted.The system errors were calculated.The distribution characteristics of the systematic errors and their relationship with the gantry angle were analyzed.Results Considered with the historical data,the means of the systematic errors of the gantry angle,diaphragm angle,JAW and monitor unit were all near 0,without obvious distribution characteristics.The systematic errors of transverse JAW(X1 and X2),longitudinal JAW(Y1 and Y2)and multi-leaf collimator(X1 and X2,leaf pair)were 0.30,0.22,0.50 mm and the deviation directions were opposite;The systematic errors of the JAW in X1 and X2 directions changed with the gantry angle as a sinusoidal trigonometric function,and the systematic errors of the multi-leaf collimator were normally distributed with the gantry angle.Conclusions All errors of Elekta Precise linac are in the permissible ranges.The systematic errors of the JAW in X1 and X2 directions changed with the gantry angle as a sinusoidal trigonometric function,and the systematic errors of the multi-leaf collimator are normally distributed with the gantry angle.There is no significant difference in the systematic error in and out field.There is almost no deviation in the monitor unit.The systematic errors of the gantry angle,diaphragm angle,JAW(Y1 and Y2)have no obvious distribution laws.