ABSTRACT
Positron emission tomography (PET) and single-photon emission tomography (SPECT) detect radionuclides and their interactions with biochemical processes in living subjects. These radionuclide imaging modalities are routinely used in the clinic for a variety of diagnostic purposes. Due to their exquisite subnanomolar (10−11 to 10−10 M) sensitivity, PET and SPECT are able to measure biological processes at very low concentrations. The mass of radionuclides can be injected in tracer quantities and generally does not affect the biological system of the host.
