摘要
The purpose of this study was to evaluate the clinical application of a rotating pod and assess its dosimetric considerations,positional accuracy,and anatomical structure stability.A pre-dosimetric study conducted on 11 patients revealed the potential for lung dose reduction using the rotational pod.Subsequently,seven patients underwent treatment with the rotational pod,and the target coverage and organs at risk doses were compared with those of conventional methods.The positional accuracy of the rotational pod,in collaboration with the imaging guidance system,was analyzed.The Dice similarity coefficient(DSC)was used to assess the settlement of tumors,trachea,and thoracic vertebrae after rotation for 20 min.In the pre-dosimetric study,there was no statistically significant difference in the volume of the internal gross tumor volume receiving≥99%of the prescription dose between the pod and conventional couch plans.However,compared to conventional couch plans,pod plans demonstrated a significant reduction in the average lung dose by 5-53%(p<0.01).Patient accrual,comprising seven cases,revealed reduced lung doses(9-26%)in four patients.For the other three patients,although there was no significant reduction in the lung dose,the use of the 90°beamline contributed to a decrease in the patient admission waiting time.The positional errors between the beams for lateral,longitudinal,vertical,ISO,pitch,and roll directions were 0.0 mm±5.3 mm,-1.2 mm±2.3 mm,-1.1 mm±2.7 mm,0.0°±0.6°,-0.1°±0.5°,and 0.0°±0.8°,respectively.The DSC for the target region and thoracic vertebrae between CT images captured before and after a 20-min rotation was higher than 0.85,whereas the DSC for the trachea was approximately 0.8.The preliminary clinical application of the rotational pod for lung tumors in fixed ion beamlines shows promise for achieving target coverage,reducing lung dose,and maintaining position accuracy.
基金
supported by the Shanghai Municipal Health Commission Funds(No.20214Y0026).
