The promise of nuclear medicine technology: status and future perspective of high-resolution whole-body PET.

Positron emission tomography has rapidly emerged over the past 50+ years resulting in highly sophisticated tools for medical diagnosis. However, spatial resolution is still one of the drawbacks of PET. Modern whole-body PET devices provide a spatial resolution in the range of 4-6mm FWHM. Physical constraints are equally responsible for limited spatial resolution as factors caused by geometrical effects or by detector crystal properties. This paper focuses on the question why it is still a major challenge--despite the invention of new crystals and readout electronics--to build a high-resolution whole-body PET system for humans. Physical constraints are discussed and possible solutions for high-resolution PET are presented.