Study on efficacy improvements and quality of the protontherapy treatments

Abstract

The research in protontherapy is being configured today a new era where new objectives in term of quality treatment improvement are reached and new methodologies to increase the radiobiological effect are investigated. This thesis includes both these aspects. The first part of the work is dedicated to a new proposed methodology based on a nuclear reaction triggered by clinical protons. I report the first experimental proof of the PBCT (Proton Boron Capture Therapy) technique based on the use of the p+11B=>3a nuclear fusion reaction to enhance proton biological effectiveness exclusively in the tumour region through the generation of short-range high-LET alpha particles, thus being of potential clinical worth. Another important item in the protontherapy research consists of investigations about the improvements in the treatments quality. In this thesis, Monte Carlo approach has been evaluated as a new promising strategy for the calculation of the main parameters of interest in medical physics and radiobiological applications. A systematic study to identify the best algorithm for the Linear Energy Transfer (LET) calculation has been performed. This resulted in a new proposed algorithm and its application for the radiobiological effect estimation (or RBE). A work on the proton therapy quality improvement cannot neglect a precise beam characterization as well as the optimisation of its transport parameters. Accordingly, a special task was focused on the improvement of the INFN (Istituto Nazionale di Fisica Nucleare) multidisciplinary facilities: LNS (Laboratori Nazionali del Sud) and TIFPA (Trento Institute for Fundamentals Physics Applications). The main intent has been to increase the beam quality and the techniques for its monitoring. Systematics studies to realize a scattering system for high energy proton and light ions beams (12C, 4He, 16O) as a well as a passive system for the beam energy modulation have been performed. In the end, a new detector for the online dose profiler acquisition has been developed and characterized for its future installation in the abovementioned facilities.