Final answer:
A positron emitting radiopharmaceutical, such as FDG, is used in PET scans to create three-dimensional images that show the functional metabolism of glucose in the body, which helps in diagnosing various health conditions, including cancer, heart disease, and brain disorders.
Step-by-step explanation:
A positron emitting radiopharmaceutical like fluorodeoxyglucose (FDG) is used in positron emission tomography (PET) scans to diagnose and track health conditions. FDG, a glucose analog tagged with a positron-emitting radioisotope like F-18, is injected into the patient. As cancer cells consume glucose at a higher rate, they take up more FDG, which emits positrons. Upon meeting electrons, annihilations occur that emit pairs of gamma rays traveling in opposite directions. These are detected by PET scanners, enabling the production of detailed, three-dimensional images that reveal functional information about the body's tissues and organs.
PET scans are particularly useful for detecting metabolically active cancerous tissue, assessing heart disease and damage, diagnosing Alzheimer's disease, and evaluating brain disorders. Unlike other imaging techniques such as MRI and CT, PET provides functional rather than structural information. It is now commonly paired with computed tomography (CT) scans to provide complementary diagnostic information.