Abstract: The IRIS group at IFIC-Valencia has developed a second version of a Compton camera prototype for hadron therapy treatment monitoring, with the aim of improving the performance with respect to its predecessor. The system is composed of three Lanthanum (III) bromide (LaBr3) crystals coupled to silicon photomultipliers (SiPMs). The detector energy resolution has been improved to 5.6% FWHM at 511 keV and an angular resolution of 8.0 degrees has been obtained. Images of a Na-22 point-like source have been reconstructed selecting two and three interaction events. Moreover, the experimental data have been reproduced with Monte Carlo simulations using a Compton camera module (CCMod) in GATE v8.2 obtaining a good correlation.