End-To-End Procedure For IORT in Brain Metastases and Film Dosimetry

PURPOSE: The study is intended to perform an end-to-end test of the entire intraoperative process using cadaver heads. A simulation of tumor removal was performed, followed by irradiation of the bed and measurement of absorbed doses with radiochromic films. MATERIALS AND METHODS: Low-energy X-ray intraoperative radiotherapy (IORT) was used for irradiation. A computed tomography study was performed at each site and the absorbed doses calculated by the treatment planning system, as well as absorbed doses with radiochromic films, were studied. RESULTS: The absorbed doses in the organs at risk (OAR) were evaluated in each case, obtaining maximum doses within the tolerance limits. The absorbed doses in the target were verified and the deviations were <1%. CONCLUSIONS: These tests demonstrated that this comprehensive procedure is a reproducible quality assurance tool which allows continuous assessment of the dosimetric and geometric accuracy of clinical brain IORT treatments. Furthermore, the absorbed doses measured in both target and OAR are optimal for these treatments.