Original Research
YU Liangjie, GAO Meimei, ZHANG Wenzheng, XUE Jun
Objective: This study aims to evaluate the correction effect of adaptive radiotherapy (ART) based on fan beam CT (FBCT) and image-guided radiotherapy (IGRT) using the uLinac HalosTx medical linear accelerator on the setup errors of tumor patients. It also analyzes the impact of the planning duration of ART on body position stability, with the intention of providing a reference for clinical optimization of ART procedures.
Methods: Using a retrospective cohort analysis, 27 patients with malignant tumors (5 patients with esophageal cancer, 13 patients with cervical cancer, and 9 patients with prostate cancer) admitted to Renji Hospital, Shanghai Jiao Tong University School of Medicine from September 2024 to March 2025 were included. Through FBCT three-dimensional registration technology, the setup errors in the X (Lat), Y (Lng), and Z (Vrt) directions were measured before and after the ART plan was formulated, and the impact of different durations of ART planning (0-20 min, >20-25 min, >25 min) on the setup errors was analyzed.
Results: The setup errors in the X (Lat), Y (Lng), and Z (Vrt) directions in patients with esophageal cancer decreased from 0.190±0.131 cm, 0.197±0.152 cm and 0.267±0.208 cm, respectively, to 0.098±0.062 cm, 0.094±0.092 cm and 0.074±0.057 cm (P<0.001); the setup errors in patients with cervical cancer decreased from 0.185±0.131 cm, 0.331±0.270 cm and 0.244±0.209 cm, respectively, to 0.066±0.085 cm, 0.133±0.096 cm and 0.087±0.073 cm (P<0.001); the setup errors in the patients with prostate cancer decreased from 0.169±0.137 cm, 0.294±0.221 cm and 0.279±0.177 cm, respectively, to 0.052±0.067 cm, 0.132±0.125 cm and 0.084±0.079 cm (P<0.001). The relationship between the duration of ART planning and setup errors showed that there were no significant differences in the setup errors in the X (Lat), Y (Lng) and Z (Vrt) directions in patients with esophageal cancer among different duration groups (P>0.05); however, there were significant differences in the setup errors in patients with pelvic malignancies among different duration groups (P<0.05), with increase in the setup errors in the three-dimensional directions as the duration of planning increased.
Conclusion: ART can effectively improve setup accuracy and significantly reduce the setup errors in patients with esophageal, cervical or prostate cancer. However, for patients with pelvic malignancies, it is recommended to strictly control the duration of ART planning to avoid the accumulation of setup errors caused by prolonged time.