Validating the Dosimetric Parameters of INTRABEAM Intraoperative Radiotherapy Machine

BACKGROUND AND OBJECTIVE: One of the methods for treating breast cancer is radiotherapy using low-kV X-rays in which a dedicated device called INTRABEAM is used along with a few spherical applicators for breast radiation. Due to the single-session nature of this treatment, evaluating the accuracy of the device used for treatment is essential. The aim of this study was to evaluate the dosimetric parameters of the INTRABEAM system with spherical applicators and validate the reported results for clinical use in intraoperative radiotherapy for breast tumors. METHODS: In this study, dosimetric parameters including percentage depth dose curve (PDD), transfer function (TF) and anisotropy were determined by MCNPX Monte Carlo Simulation Tool and practical dosimetry was done by Gafchromic EBT2 film. The results were quantitatively compared with the results reported by manufacturer of the device (Carl Zeiss) to evaluate the accuracy of the reported data for this treatment system. FINDINGS: The mean difference when comparing PDD curves was 1.7% and the mean difference between the compared TF values was about 2%. The anisotropy values obtained by Monte Carlo Simulation and Gafchromic EBT2 film were also within the range recommended by the manufacturer. CONCLUSION: Based on the results, it can be concluded that the dosimetric parameters reported by the manufacturer for spherical applicators of the INTRABEAM system are valid for designing the treatment and radiotherapy for patients