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

CHEN Ying; CHEN Fei; GONG Xiaoqin; HUANG Jian; YANG Wuyang; YOU Tao; DAI Chunhua; HU Jing

doi:10.3969/j.issn.1006-5725.2024.17.014

Abstract：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.