Abstract: Background and purpose: Currently, intraoperative radiation therapy (IORT) has become the adjuvant therapy of cancer. The study was to establish the daily quality assurance (QA) program and analyze dosimetric characteristics’ long-term stability for mobile IORT accelerator. Methods: The QA program of this study included two parts: safety and functionality and energy and output. The two years’ QA datasets were acquired and analyzed to investigate the stability of energy and output. Results: All safety and functionality tests passed on a daily basis. The energy index was (0.666±0.015)mm, (0.839±0.009)mm, (0.781±0.010)mm, (0.724±0.009)mm and the output dose error was (0.511 ± 0.671)%, (0.278 ± 0.516)%, (0.368 ± 0.532)%, (0.382 ± 0.912)% for all energy, respectively. There was no significant time trend in the dosimetric characteristics. Conclusion: The daily QA program is suitable for mobile IORT accelerator. The long-term stability is acceptable for IORT in clinical use.

Key words: Intraoperative radiation therapy, Quality assurance, Long-term stability