what is a pet scan (pet/ct scan)? A PET scan is a powerful tool used by doctors when evaluating patients who may or may not have cancer. PET is a primary imaging modality for the detection and tracking of cancer. Nuclear imaging (PET and SPECT) are also considered a standard of care for myocardial perfusion exams to see if there is a lack of blood flow to the heart muscle due to a heart attack. It allows them to effectively diagnose and evaluate cancer and whether or not it has spread to other areas of the body. Positron Emission Tomography (PET) Imaging Diagram courtesy of Bioteach at UBC Positron emission tomography (PET) imaging is a nuclear medicine imaging technique that can be used to non-invasively elucidate biochemical processes, diagnose disease and track the impact of experimental drugs in clinical trials – all in living human subjects.