A positron emission tomography scan is conducted by administering a radioactive tracer chemical to the patient and using a full-body scanner to detect how the substance interacts with tissues, organs and blood, states MedlinePlus. The radioactive signals tracked by the scanner are converted into electronic images.
PET scans are used to evaluate the functionality of organs, identify signs of organ failure and analyze the body's response to medical treatments, Medical News Today notes. The patient is instructed to abstain from eating for at least four hours before the scan, and the radiotracer is administered by needle injection or inhalation. The body is given 30 to 90 minutes to fully circulate the radiotracer.
During the test, the patient lies still on a table that slides inside the large scanner. The radiotracer indirectly marks its path through the body by emitting positively charged particles, or positrons, according to MNT. The scanner picks up on this residual energy, and a computer compiles the data into a 3-D picture. Different areas of the body have distinct absorption patterns when interacting with the radiotracer, so radiologists use PET scans to identify abnormalities. For example, technicians can verify the source of heart disease by pinpointing areas where cardiac tissue isn't functioning properly and may be damaged.