体表监测系统在胸部肿瘤调强放疗中的应用

Application of surface monitoring system for thoracic tumors treated with intensity modulated radio⁃therapy

目的 探讨体表监测系统(ExacTracDynamic, ETD)辅助摆位和体表监测功能在胸部肿瘤患者调强放疗中应用的可行性。方法 选取进行放疗的胸部肿瘤患者,入组患者交替行常规十字标记线摆位(对照组)和体表监测系统辅助摆位(观察组)。治疗前均用ETD的X线影像行摆位校准,在胸骨上勾画感兴趣区并实时体表监测患者治疗中的位置变化,治疗结束后再行X线影像验证。记录左右(X)、头脚(Y)、腹背(Z)、俯仰(Pitch)、横滚(Roll)、旋转(Yaw)方向上的数据并比较分析。结果 入组60例患者,对照组放疗754次,观察组718次。观察组在X和Z方向的摆位误差小于对照组(P <0.05);观察组在X≤0.50 cm、Y≤0.50 cm、Z≤0.50 cm和Roll≤1.00°方向的摆位误差次数均大于对照组(P <0.05);体表监测和治疗后的位置偏差在Y和Z方向上存在差异性(P <0.05),但均值在亚毫米级。结论 体表监测系统辅助摆位可提高胸部肿瘤患者放疗摆位的精度,尤其在X和Z方向。感兴趣区设置在胸骨上时,体表监测能较好地反映患者靶区内部位置的变化。

Objective To assess the feasibility of utilizing the ExacTracDynamic surface monitoring system(ETD)for setup and body surface monitoring in patients with thoracic tumors undergoing intensity-modulated radio-therapy(IMRT).Methods Patients receiving IMRT for thoracic tumors were included in this study.The enrolled patients were alternatively assigned to either conventional cross curve positioning(control group)or surface monitoring system-assisted positioning(experimental group).ETD X-ray images were utilized for calibration purposes prior to radiotherapy,enabling the determination of setup errors.A region of interest(ROI)was delineated on the body surface above the sternum,and real-time body surface monitoring was performed based on this ROI during radiotherapy.Post-radiotherapy X-ray images were obtained to verify patient position.Data regarding left-right(X),head-foot(Y),abdomen-back(Z),pitch,roll,and yaw directions were recorded and analyzed.Results A total of 60 patients were enrolled,with 754 fractions of radiotherapy in the control group and 718 fractions in the experimental group.The setup errors in the X and Z directions were significantly smaller in the experimental group compared to the control group(P<0.05).Moreover,there was a significant reduction in the number of setup errors≤0.50 cm for X,Y,and Z directions,as well as≤1.00°for Roll angle in the experimental group compared to the control group(P<0.05).Additionally,differences were observed between surface monitoring and X-ray image verification regarding position deviation along Y and Z directions(P<0.05),although these deviations remained within submillimeter levels on average.Conclusion Surface monitoring system-assisted positioning can enhance radiotherapy setup accuracy among thoracic tumor patients,particularly along X and Z directions.Furthermore,when setting ROI above sternum on body surface area,surface monitoring provides better reflection of target area's position deviation.