Skin marker combined with surface‐guided auto‐positioning for breast DIBH radiotherapy daily initial patient setup: An optimal schedule for both accuracy and efficiency.

Background and purpose: By employing three surface‐guided radiotherapy (SGRT)‐assisted positioning methods, we conducted a prospective study of patients undergoing SGRT‐based deep inspiration breath‐hold (DIBH) radiotherapy using a Sentine/Catalys system. The aim of this study was to optimize the initial positioning workflow of SGRT‐DIBH radiotherapy for breast cancer. Materials and methods: A total of 124 patients were divided into three groups to conduct a prospective comparative study of the setup accuracy and efficiency for the daily initial setup of SGRT‐DIBH breast radiotherapy. Group A was subjected to skin marker plus SGRT verification, Group B underwent SGRT optical feedback plus auto‐positioning, and Group C was subjected to skin marker plus SGRT auto‐positioning. We evaluated setup accuracy and efficiency using cone‐beam computed tomography (CBCT) verification data and the total setup time. Results: In groups A, B, and C, the mean and standard deviation of the translational setup‐error vectors were small, with the highest values of the three directions observed in group A (2.4 ± 1.6, 2.9 ± 1.8, and 2.8 ± 2.1 mm). The rotational vectors in group B (1.8 ± 0.7°, 2.1 ± 0.8°, and 1.8 ± 0.7°) were significantly larger than those in groups A and C, and the Group C setup required the shortest amount of time, at 1.5 ± 0.3 min, while that of Group B took the longest time, at 2.6 ± 0.9 min. Conclusion: SGRT one‐key calibration was found to be more suitable when followed by skin marker/tattoo and in‐room laser positioning, establishing it as an optimal daily initial set‐up protocol for breast DIBH radiotherapy. This modality also proved to be suitable for free‐breathing breast cancer radiotherapy, and its widespread clinical use is recommended. [ABSTRACT FROM AUTHOR]