Focus on time-of-flight PET: the benefits of improved time resolution

TOF PET is characterized by a better trade-off between contrast and noise in the image. This property is enhanced in more challenging operating conditions, allowing for example shorter examinations or low counts, successful scanning of larger patients, low uptake, visualization of smaller lesions, and incomplete data sampling. In this paper, the correlation between the time resolution of a TOF PET scanner and the improvement in signal-to-noise in the image is introduced and discussed. A set of performance advantages is presented which include better image quality, shorter scan times, lower dose, higher spatial resolution, lower sensitivity to inconsistent data, and the opportunity for new architectures with missing angles. The recent scientific literature that reports the first experimental evidence of such advantages in oncology clinical data is reviewed. Finally, the directions for possible improvement of the time resolution of the present generation of TOF PET scanners are discussed.