Positron emission tomography

Abstract

The potential of the coincidence technique in positron imaging was recognized early on and pilot experiments were performed as early as the 1950s. In combination with the tomographic technique, it was possible in the late 1970s to demonstrate a new principle for medical diagnosis, positron emission tomography (PET). In more recent years PET has matured and has become an important clinical research tool, as well as a routine diagnostic modality. PET is a multidisciplinary undertaking. However, in this paper we mainly emphasize the contribution from nuclear physics, radionuclide production and detector development. New crystal materials with high density, high light output and short pulse length will, in the near future, improve the resolution and counting properties of PET instrumentation. The experience gained in the development of -detectors in nuclear and particle physics is applied to increase the solid angle and hence the sensitivity. Other factors must also be considered. There is interest in using positron-emitting nuclides with longer half-lives than those mainly associated with PET. Many of these long-lived nuclides, e.g. ( h) and ( h), emit high-energy gamma radiation in coincidence with the positron radiation, which will affect the detection and quantification abilities of PET. PET primarily yields functional and physiological information, and anatomical structures are sometimes difficult to identify. High-quality PET data usually have to be combined with an anatomical method like CT or MRI. The future will, besides highly sophisticated and dedicated PET systems for research, probably see clinically suited rotating gamma cameras integrated with CT or MR, which can efficiently be used both for SPECT and PET.