First Results from All-Digital PET Dual Heads for In-Beam Beam-On Proton Therapy Monitoring

Novel technological solutions for the design of positron emission tomography (PET) systems to be used in the in-beam beam-on monitoring of proton tracks within biological tissues represent the frontier of the instrumentation in proton therapy. We report a novel all-digital PET dual heads prototype based on the multivoltage threshold (MVT) technology, able to operate in beam-on modality. We demonstrate in phantom and animal experiments that, by using an event selection based on the energy of singles and on the delay with respect to the radio-frequency period of the proton beam bunches, the monitoring PET system is able to image the induced activity by both pristine and pencil proton beam with energy ranging between 70 and 150 MeV during irradiation.