Development of an innovative device for beam range monitoring in particle therapy

The Particle Therapy (PT) is a particular kind of radiation therapy in which accelerated light ions beams are exploited instead of photons, commonly used in conventional radiotherapy. One of the most advantageous PT features is its capability to achieve high localised dose distributions, allowing to concentrate most of the energy release in the tumour volume. As a results, the undesired amount of radiation absorbed by the healthy tissues is minimised, and the probability of side effects occurrence is reduced. One of the most important still open issue in PT is represented by the treatment quality assurance, since a control system capable to provide a real-time feedback on the dose distribution actually delivered to the patient is missing in the clinical practice. In PT the capability to deliver the dose at a certain depth depends from the capability to properly predict the beam range in the patient, then the scientific community have addressed several researches to develop on-line beam range verification techniques. In PT the primary beam particles does not escape from the patient, and the most followed approach consists of an indirect range measurement, exploiting the secondary particles produced due to the nuclear interaction between the beam projectiles and the crossed tissues nuclei. In this Ph.D. thesis an innovative range verification technique that exploits charged secondary fragments, particularly suitable for 12C ion treatments, is proposed. In particular, the development of a detector, named Dose Profiler (DP) and specifically designed for this purpose, is presented. The detector, assembled and tested using a proton beam in 2017, has been included in a clinical trial that will be performed at CNAO. The DP design and the performances measured using MIPs and protons are reviewed, as well the preliminary results obtained in a test with an anthropomorphic phantom. The feasibility of the proposed technique is discussed .