The fundamental imaging relies on radioactive molecule (radio tracer) that decays with positron emission .

Method

• The radiotracer (FDG ) is given intravenously to the patient
• FDG taken into cells. And cell recognizes it as being “Foreign”
• Trapped early in its metallic pathway.

(Malignant cells trap more radio-tracer compared c non-malignant cells)

• Position travels a short distance in tissue before colliding c electrons
• Annihilation reaction resulting 2 photons known as gamma rays of 511 Kev.
• The photon are detected by opposing electron
• Computer resemble these signals into images which represent radio active tracer uptake in the part of body scanned.