David Santiago Ayala Alvarez

Miniature kV x-ray tubes for electronic brachytherapy are used in intraoperative radiotherapy (IORT) applications to improve the outcome of cancer treatments. The implemented low-energy electronic method is found to be a convenient alternative to interstitial brachytherapy with radionuclides, reducing the inherent safety risks and shielding, yet with a higher dose rate. The INTRABEAM system is one of the most distributed examples of these sources, which is calibrated using the manufacturer’s own protocol. A comprehensive and feasible dosimetry protocol for electronic brachytherapy is essential and is in active research. In our project, a brachytherapy dosimetry model based on a modified version of the TG-43 protocol for the INTRABEAM source was developed. In addition, the dose distributions in water were determined with the PTW TN60019 synthetic diamond detector, which presents improved characteristics over the PTW 34013 such as precisely defined dimensions and a reduced radiation sensitive volume. Monte Carlo models for both methods were validated based on measurements in water. The validated methods will be used to calculate dose to patient tissues and to establish optimized combinations of INTRABEAM with EBRT, studying the radiobiological implications.