The effect of age on skin elasticity and setup error in optical surface image-guided radiotherapy

Objective To investigate the correlation between skin elasticity and setup error in optical surface image-guided radiotherapy. Methods The skin elasticity (R7) data of the head, chest and abdomen were extracted and analyzed its correlation with age by systematic literature review. Fifty-four patients diagnosed with nasopharyngeal carcinoma, breast cancer and cervical cancer were recruited in this study. Firstly, the patients were positioned based on the room laser and markers. Subsequently, the patient position was verified by the Varian On-Board Imager, and then C-Rad Catalyst was adopted to obtain surface images in two states (mask or non-mask) as reference images. In the subsequent fraction treatment, after initial positioning, the local calibration was performed by Catalyst, and setup errors in three directions were recorded. Meanwhile, the patient setup was verified by CBCT twice a week. The Pearson correlation analysis was performed to analyze the correlation between setup error and age. Results The skin elasticity was negatively correlated with aging (P SI>AP. Conclusion In optical surface-guided radiotherapy of head and neck cancer, skin elasticity may be a significant index for assessing the setup errors in male patients. Key words: Skin elasticity; Surface image-guided radiotherapy; Set-up error