ABSTRACT
This chapter describes the physics of positron emission tomography (PET) together with a short overview of data quantification and reconstruction and data analysis and interpretation. A PET scanner is designed to provide a measurement of the spatial distribution of a PET radiotracer within a subject. PET utilizes radiotracers labeled with positron-emitting radionuclides designed to selectively target specific processes or sites of interest. A valid PET event is comprised of the detection of the two annihilation photons within a temporal interval by two different, opposing detectors. The definition of detector pairs that can accept a coincident event defines the imaging field of view. Modern small animal PET scanners have detectors that provide sufficiently high spatial resolution for the positron range–derived image degradation to be noticeable. An important characteristic of PET is its potential to provide quantitative data, that is, to provide a measure of counts that is proportional to the underlying radioactivity concentration anywhere in the object.
