PET technology has been applied to the early diagnosis and therapeutic responses in lung, colorectal, breast, ovarian, lymphoma, melanoma, and prostate cancers.
Recently, Phelps and his co-workers developed an approach to imaging gene expression that promises to be an important contribution to the rapidly expanding field of molecular medicine.
Phelps' initial work dealt with the application of basic nuclear physics, chemistry, and mathematics to biomedical imaging.
He combined a number of original insights in developing PET: First, he recognized that positron decay provides the opportunity for a unique coincidence detection system, with opposing detectors.
Second, using the principle of coincidence detection, he configured a circumferential array of detectors and associated electronics and a mathematical algorithm for forming three-dimensional tomographic images of biological probes of the living human body.
Finally, he recognized that the positron-emitting forms of oxygen, nitrogen, carbon and fluorine provide the tools to "label" biochemical molecules for their use as probes, to non-invasive image biological processes in living individuals.