The new opportunities for high time resolution clinical TOF PET

Time-of-flight (TOF) positron emission tomography (PET) traces its origins to the beginning of PET itself. A brief historical review will be followed by a discussion of the recent development in silicon photomultipliers (SiPM), which has generated a quality leap in TOF performance. The principles of TOF PET physics and a discussion of the technical and clinical advantages of TOF PET compared to conventional PET will be presented: the concept of time resolution and its effect on TOF gain in signal-to-noise ratio, together with other properties such as reconstruction robustness to inconsistent data, convergence, and convergence speed. Finally, new exciting challenging applications enabled by very high-performance TOF PET scanners in the field of low count imaging, such as 90 Y imaging and theranostics, will be discussed.