Brain scan

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  • Lipophilic agent crosses BBB, rapid intracellular uptake in proportion to blood flow, fixed intracellularly
  • Provides snapshot of blood flow at time of injection


Increased activity can also be seen with sensory/motor stimulation


  • Hypometabolic on interictal scan
  • Hypermetabolic on ictal scan

Alzheimer's Disease - decreased uptake in the bilateral posterior parital regions

Pick's Disease - decreased uptake in the bilateral anterior frontal and anterior temporal regions

Multiinfarct Dementia - multiple asymmetric defects

Huntington's Disease - decreased uptake in basal ganglia


  • Can also be used to differentiate brain neoplasm and infection in AIDS patients for example *FDG-PET, TI210 and Tc99m all demonstrate increased activity with malignancy and low uptake with infection
  • Can differentiate residual tumor (hot) and radiation necrosis (cold)

Parkinson's Disease

  • Normal on PET
  • Certain agents developed from the DOPA pathway (tyrosine) do show increased activity