Compton imaging in proton therapy: reconstructed image of the simulated prompt-γ distribution
Résumé
Purpose: In proton therapy cancer treatments, interactions between the beam and the patient's body lead to nuclear reactions that produce secondary prompt-γ radiation. It was shown that some correlation exists between those photons and the Bragg peak position, and works are ongoing to design imaging systems in order to monitor the deposited dose by exploiting prompt-γ. Teams obtained encouraging results on the performance of the Compton camera for in vivo dosimetry in hadron therapy. The Compton camera detects a photon in two steps. The photon is scattered (at least once) in a first detector (in silicon in our case), then it is absorbed in a second detector (in LYSO). The hits, recorded with positions and energies, define an event. For each event, a Compton cone is defined and the incoming path of the initial ray lies on its surface. The image of the source is then calculated by tomographic reconstruction from projections calculated on conical surfaces. The goal of this work is to assess the ability of the reconstruction algorithms to faithfully calculate the image of the prompt-gamma distribution.