We developed a PET detector prototype based on detection of prompt Cherenkov light (ARRS J2-1735 grant) and demonstrated a twofold improvement in time-of-flight (TOF) resolution compared to current state-of-the-art commercial scanners. In a simulation study, we showed that with sufficient advance in photodetector technology, this novel detection approach has the potential of tenfold improvement in TOF. Using Cherenkov light also enabled us to construct a PET detector module from materials enabling a fivefold reduction in price. A simulation evaluation of the silicon PET probe insert showed that a significant improvement is gained if a probe is placed in proximity of the image object, evaluated through standard image quality measures.