Improving MACACO, a Compton Telescope for Treatment Monitoring in Hadron Therapy

The IRIS group of IFIC-Valencia has developed and fully characterized a first version of MACACO (Medical Applications CompAct COmpton camera), a three-layer Compton telescope based on LaBr ₃ crystals and SiPMs for treatment monitoring in hadron therapy. Results obtained in laboratory and beam tests have demonstrated the feasibility of the proposed technology. The limitations of this first version of MACACO have been identified, being energy resolution one of the most critical parameters in the system performance. For this reason, an improved version of the detectors employing a new SiPM array has been assembled. Characterization tests have been performed. Also, coincidence tests have been carried out with two new detectors operated in time coincidence. Point-like sources and an array of 37 point-like sources have been imaged. Tests with the new detectors show a general improvement of the device performance.