Pet Scan
  • 2-[18F]-Fluoro-Deoxy-D-Glucose (18F-FDG)
    • Positron emitting glucose analog
    • Transported into cell
    • Phosphorylated by hexokinase ==> FDG-6-phosphate
      • No more phosphorylase pathway —> stay trapped within cells
      • Progressive accumulation of F-FDG in tissues with higher metabolism

What is specific to tumour cells so there will be F-FDG accumulated?

  • increased activity of hexokinase II
  • increased expression of glucose transporter
  • dowwnregulation of glucose phosphotase enzyme

So then what happens?

  • positron emitted travels about 1mm
  • then combines with an electron ( annihilation )
  • emition of TWO 511-keV photons
    • They travel 180 degree from each other
    • Detected at the same time —> define a line of sponse

Normal distribution of F-FDG :

  • brain
  • blood pool
  • urinaru activity —> renal collecting system
  • bladder
  • smooth and striated muscles
    • Will be increased in presence of insulin —> that's why patient is asked to be fasting…

Overall PET has low spatial solution.