Hi there, you may be referring to PET scan (positron emission tomography). PET scan is an imaging technique
that allows quantification of the body's abnormal molecular cell activity to detect cancer, brain
pathology as well as heart Disease. Commonly, a small amount of radioactive material is injected intravenously
into the patient; hence, the radiation will be coming directly from the patient. PET scan is a functional
imaging technique as opposed to the conventional imaging procedures (e.g. ct-scan, x-ray) that are considered
anatomical imaging technique. Additionally, PET scan uses gamma camera in detecting radiation coming from the
patient. Hope this info helps you.