Positioning error and dose verification of stereotactic radiotherapy for lung cancer based on cone beam CT
[Objective]To study the impact of different arm fixation methods on patient position error and dose verification analysis in stereotactic body radiation therapy(SBRT)for lung cancer.[Methods]Thirty-four patients who were admitted to the Oncology Department of the Third Xiangya Hospital Affiliated to Central South University and underwent pulmonary SBRT from March 2019 to December 2022 were selected,and their arms were fixed by holding the rod with both hands crossed(Control group)and holding the elbows with both hands on the forehead(Observation group).Cone beam computed tomography(CBCT)was used for each patient's treatment.The CBCT scan image was automatically matched with the image during CT simulation positioning,and the target area and bony landmarks were adjusted.The patient's error in the X,Y,and Z axis directions was calculated and analyzed.At the same time,the threshold standards as(2％,2mm,10％)and(3％,3mm,10％)were selected to analyze and compare the ArcCHECK phantom.The difference between the theoretically calculated dose and the measured dose on the ArcCHECK phantom was analyzed.[Results]A total of 510 sets of CBCT images were obtained from 34 research subjects.The position errors of patients in Control group and Observation group before each treatment were respectively LAT(1.69±4.43 and 2.25±1.54)in the left and right directions,LNG(1.88±1.39 and 2.40±1.61)in the head and foot directions,and ventral and dorsal VRT(1.26±0.98 and 1.70±1.08).The error values of Control group in the three directions of X,Y,and Z were smaller than those of Observation group,and the differences were statistically significant(P＜0.05).When the threshold standard is(2％,2mm,10％),the absolute pass rates of both groups of SBRT plans are greater than 95％;when the threshold standard is(3％,3mm,10％),the absolute pass rates of both groups of SBRT plans are all greater than 90％,meeting clinical treatment requirements.[Conclusion]In the SBRT treatment of lung cancer,the absolute dose pass rates of the two arm fixation methods verified based on the ArcCHECK phantom meet clinical requirements,but the arm fixation method with hands crossed and holding the rod has better repeatability and accuracy for patient positioning.
cone beam CTstereotactic body radiotherapypositioning errordose verification
万方数据
维普
