摘要
Abstract
Background and purpose:In recent years,deep inspiration breath hold(DIBH)based on surface-guided radiation therapy(SGRT)has emerged as one of the most promising techniques in breast cancer radiotherapy.Conventionally,cone-beam CT(CBCT)is used before treatment to verify and correct patient positioning deviations.However,patient position may change during treatment,and pre-fraction CBCT cannot fully reflect real-time positional deviations.Therefore,this study aimed to introduce intra-fraction CBCT into left-sided breast DIBH radiotherapy to monitor and correct real-time deviations,verify whether patients achieve the desired position during treatment,and evaluate the clinical value of intra-fraction CBCT in left-breast radiotherapy.Methods:Clinical data from postoperative left-sided breast cancer patients treated at Fudan University Shanghai Cancer Center between June 2023 and January 2024 were collected.Patients with satisfactory cardiopulmonary function and stable DIBH compliance were included.Pre-fraction CBCT scans were performed before treatment,and data were recorded.During treatment,the gantry was rotated to-180° to trigger kV-level intra-fraction CBCT scanning.After gantry repositioning to the starting angle of the tangential field,MV beam delivery commenced.Intra-fraction CBCT scans were acquired for positional registration,and deviations were compared with pre-fraction CBCT results.Results:A total of 30 eligible patients were included,with 150 pairs of pre-fraction and intra-fraction CBCT images analyzed per patient.The mean registration deviations for intra-fraction CBCT were 26%,52%,and 51%lower than pre-fraction CBCT in the X,Y,and Z axes,respectively(P＜0.05),demonstrating significantly reduced real-time deviations.The probability of intra-fraction deviations being＜6 mm was 100.0%,100.0%,and 99.3%for the X,Y,and Z axes,respectively.Correlation analysis revealed a weak correlation between intra-fraction and pre-fraction deviations in the X-axis(P＜0.05),while no significant correlation was observed for the Y and Z axes(P＞0.05).Conclusion:Intra-fraction CBCT effectively monitors and corrects real-time positional deviations in left-sided breast DIBH radiotherapy,serving as a valuable supplement to conventional pre-fraction CBCT.It minimally impacts treatment efficiency while significantly improving positional accuracy,offering clinical and practical benefits for left-breast cancer radiotherapy.关键词
分次内CBCT/体表引导放射治疗/深吸气屏气技术/乳腺癌Key words
Intra-fraction CBCT/Surface-guided radiation therapy/Deep inspiration breath hold/Breast cancer分类
医药卫生
