A positron emission tomography scan can indicate heart disease, cancer, Alzheimer's and epilepsy, according to Medical News Today. Neurologists, cardiologists and oncologists frequently use PET scans in conjunction with X-rays, CT scans, ultrasound or MRIs to assess affected organs within the body.
PET scans are a form of radiology. A PET machine detects pairs of gamma rays that positron-emitting radionuclides give off and, in turn, creates three-dimensional, color images of processes within the body. A radiologist prepares a radionuclide, which may be a radioactive medicine, and tags it to a natural chemical that the body uses, states Medical News Today.
Radiologists use different types of radioactive medicines depending upon the suspected medical condition, which is typically indicated by preliminary tests. The PET machine then reveals how the body metabolizes the natural chemical tagged to a radioactive medicine, explains Johns Hopkins Medicine. Affected organs within the body use the tagged natural chemical in a particular way that reflects the nature of the ailment.
For example, the way that a particular organ's cells metabolize a radionuclide tagged to glucose potentially reveals the presence of cancer, because cancer cells use glucose differently than healthy cells, according to Medical News Today.
Another nucleotide tagged to amyloid beta, the amyloid plaques associated with Alzheimer's, enables PET machines to produce images that reveal the encroachment of brain plaque, states the Alzheimer's Association. The presence of brain plaque is not necessarily indicative of Alzheimer's, but PET scans are nonetheless useful for staging Alzheimer's in patients who have received a definite diagnosis.