Analysis of setup error and setup efficiency in SBRT for non-small cell lung cancer via a surface-guided radiation therapy system.

PURPOSE: This study evaluated setup error and efficiency in patients with non-small cell lung cancer (NSCLC) receiving stereotactic body radiation therapy (SBRT), comparing surface-guided radiation therapy (SGRT) combined with a laser alignment system versus laser alignment alone, to assess the clinical value of the SGRT-assisted setup method in SBRT for NSCLC. METHODS: A total of 80 patients with NSCLC were divided into an experimental group and a control group according to the treatment setup method. In the experimental group, an integrated fixation platform, vacuum cushions, and a cervicothoracic thermoplastic mask were used for immobilization, and a SGRT system and laser alignment system were used for setup. In the control group, the same immobilization devices were used, but only a laser alignment system was used for setup. All patients underwent pretreatment cone‒beam computed tomography (CBCT) scans. The CBCT images were registered to planning computed tomography (CT) images using grayscale registration. Translational setup errors in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP) directions and rotational errors in the pitch, roll, and rotation directions were recorded. The setup time was also recorded and compared between the groups. RESULTS: Significant differences in the overall mean setup error in all six degrees of freedom were observed between the experimental and control groups (P ≤ 0.001). Within the experimental group, the overall mean setup error differed significantly between the LR and SI directions (P = 0.006). Within the control group, significant differences were found between the SI and AP directions (P < 0.001), as well as between pitch and rotation (P = 0.001) and between roll and rotation (P < 0.001). The overall mean setup time also significantly differed between the two groups (P < 0.001). CONCLUSION: Compared with the conventional laser-guided setup method, the combination of SGRT and a laser alignment system significantly reduced setup error and shortened the setup time in SBRT for NSCLC. This approach improves setup accuracy and treatment workflow efficiency, demonstrating clinical feasibility and potential for clinical application.