Implementación y validación de herramientas de dosimetría ultra-rápida para IORT

Abstract

Intraoperative Radiation Therapy (IORT) is a special modality for cancer treatment that delivers a single high dose of radiation directly to the exposed tumor bed during the tumor resection surgery. One of the main limitations in IORT lies in the difficulties that the planning process entails, which limits the use of this technique, and a treatment planning has not been available in IORT up to now. Recently, a new tool has been introduced: radiance, the first Treatment Planning System (TPS) specifically designed for IORT. The main goal of this thesis has been the development, implementation and evaluation of a dosimetric tool capable of providing a realistic dose distribution from any intraoperative electron radiotherapy (IOERT) dedicated accelerator or Intrabeam applicator that can be used for dose treatment planning in the operating room (OR) during an IORT treatment. This dosimetric tool has been separated in three phases. First, a database of monoenergetic phase space (PHSP) files and depth dose profiles (DDPs) in water was computed with penEasy from detailed simulations of each IOERT accelerator and Intrabeam applicator. Then, the energy spectrum of these monoenergetic simulations was tuned for each device using simple experimental DDPs provided by the manufacturer to the user, obtaining an optimized PHSP file that reproduces the user's data. Finally, dose was calculated from this optimized PHSP file with an accelerated version of DPM in the case of electrons, or with the Hybrid Monte Carlo (HMC) code we have developed, in the case of the Intrabeam. The tools described in this thesis have been proven to be fast and accurate enough to be used as a TPS for any IORT device. They have been incorporated into radiance as the dose calculation algorithms of the TPS.