机器视觉在分次放射治疗中的应用研究

Application of machine vision in fractionated radiotherapy

目的开发一款精准位移实时智能捕捉系统,应用于肿瘤放射治疗过程中分次内体位误差偏移监测。方法在实验室和治疗室内模拟放射治疗环境,使用xyz三轴位移平台(LD60⁃LM)和千分表作为位移测量工具,同时运用精准位移实时智能捕捉系统监测位置偏移。另入组23例放疗患者,利用该系统监测分次内体位误差偏移。将摄像机采集到的数据与实际位移对应的偏差值进行相关的描述性分析,计算出平均值和标准偏差。结果实验室校准监测发现在20 mm以内位移的差值≤0.5 mm,50 mm位移的最大差值为1.47 mm;治疗室校准结果发现左、右摄像头均显示在yz轴对应的偏差值为±0.2 mm,中间摄像头显示在xz轴对应的偏差值为±0.31 mm;23例患者的37次放疗过程中监测中间摄像头发现5次偏离5 mm阈值,偏差最大时长和位移分别为57.2 s和9.24 mm。结论基于机器视觉原理研发的精准位移实时智能捕捉系统在肿瘤放射治疗过程中能实现实时体位偏移误差监测,但仍需进一步完善系统和服役检测。

Objective To monitor intra⁃fractional set⁃up errors in tumor radiotherapy using a real⁃time intelligent capture system for precision displacement.Methods A simulated radiotherapy environment was created in both the laboratory and the treatment room.A three⁃axis(xyz)displacement platform(LD60⁃LM)and dial gauges were used as displacement measurement tools.Moreover,a real⁃time intelligent capture system for precision displacement was developed for displacement monitoring.With 23 patients treated with radiotherapy enrolled in this study,the above system was employed to monitor their intra⁃fractional set⁃up errors in fractionated radiotherapy.Descriptive analyses were conducted on the deviations between the data captured by cameras and the actual displacement,obtaining the mean values and standard deviation.Results The monitoring calibration data from the laboratory revealed displacement differences of≤0.5 mm within 20 mm and a maximum displacement difference of 1.47 mm for 50 mm.In contrast,the calibration result from the treatment room exhibited deviations of±0.2 mm on the y-z axes,as displayed by both the left and right cameras,and±0.31 mm on the x-z axes,as displayed by the middle camera.During 37 radiotherapy sessions in 23 patients,the monitoring result from the middle camera revealed five deviations exceeding the threshold of 5 mm,with the maximum deviation duration and displacement of 57.2 s and 9.24 mm,respectively.Conclusions The real⁃time intelligent capture system for precision displacement based on machine vision can achieve real⁃time monitoring of set⁃up errors during tumor radiotherapy.Nevertheless,further improvements and service testing are necessary for this system.