SiPM based preclinical PET/MR insert for a human 3T MR: first imaging experiments

Simultaneous PET/MRI is a hybrid imaging modality which promises to play an important role in the field of molecular imaging, as it combines the outstanding soft-tissue contrast of MRI with the metabolic and functional information of PET and MRI. In addition, the possibility for true simultaneous acquisition allows for improved 4D registration which in due course may lead to enhanced image quality and image quantification. The main technical challenges of simultaneous PET/MR are the MR-based attenuation correction and the development of an MR-compatible PET detector technology. Avalanche photo diode based detectors have been already successfully integrated into preclinical as well as human systems [1,2]. Low but noticeable interferences between PET and MRI have been reported so far. Unfortunately, these implementations do not offer the measurement of time of flight (TOF) information in the sub-ns range, which is one of the drivers for high quality clinical PET and has been state-of-the-art in clinical PET/CT for the last 5 years.