Positron emission tomography (PET) is a test that uses a special type of camera and a tracer (radioactive substance) to look at organs in the body.

During the test, the tracer liquid is put into a vein in your arm. The tracer moves through your body, where much of it collects in the specific organ or tissues. The tracer gives off tiny positively charged particles (positrons). The camera records the positrons and turns the recording into pictures on a computer.

A PET scan may be used to look for cancer, check blood flow, or find out how well organs are working.