Orateur
Description
Proton therapy is a method of particle therapy that uses a beam of protons to irradiate deep-seated tumours. Unlike other forms of radiotherapy, it offers greater precision in dose deposition and cancer treatment. Dose deposition occurs mainly at the end of the proton path and there is virtually no energy deposition before that.
However, the accuracy of dose deposition is limited by uncertainties related to the range of protons inside the patient. Improving the localisation of the proton range would allow the planning target volume (PTV) to be defined closer to the tumour, making the therapy more effective.
In the context of the TIARA (Time-of-flight Imaging ARrAy) project, our aim is to monitor in real time the range of protons inside the patient during treatment by imaging the emission vertices of Prompt Gammas (PGs) resulting from nuclear interactions of protons inside the patient. This can be achieved by measuring the cumulative Time-Of-Flight (TOF) of the proton and the PG. For this, we use a beam monitor to detect protons passing through it (used as a start signal) and a number of gamma ray detectors distributed around the PTV to detect PGs (used as a stop signal). This new imaging technique is called Prompt Gamma Time Imaging (PGTI) [1].
To contribute to the development of the PGTI, we have developed a full Monte Carlo simulation using the Geant4 toolbox of the TIARA demonstrator, which includes the beam monitor and 30 PbF2 Cherenkov radiators placed around a target phantom. The simulated data is then used as a validation set for a non-trivial iterative joint inversion of the proton velocity profile and energy loss as a function of proton range from measured TOFs.
[1] M. Jacquet et al., A high sensitivity Cherenkov detector for prompt gamma timing and time imaging, Sci. Rep. 13 (2023) 3609
