Single-photon Emission Tomography SPET
Principle
uses single-photon (gamma-ray) emitting isotopes
given IV or inhaled
the resolution is lower than PET
Uses
SPET can give information about:
regional cerebral blood flow
ligand binding
Clinical uses include:
Alzheimer’s disease
When the symptomatology (e.g. hallucinations, epilepsy) occurs when the patient is not near a scanner; we can give a suitable ligand at the material time and the patient scanned afterward
Schizophrenia
reduced rCBF in frontal regions—‘hypofrontality’
Affective disorders
as that in schizophrenia, with reversal after antidepressant therapy
Alzheimer’s disease
decreased rCBF in posterior parietal and temporal regions
Xenon inhalation
Shows the failure of activation of frontal lobes in schizophrenics performing the Wisconsin Card Sorting Test
