SPECT vs PET

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Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are nuclear medicine imaging techniques which provide metabolic and functional information unlike CT and MRI.

They have been combined with CT and MRI to provide detailed anatomical and metabolic information.

Positron emission tomography (PET):

  • is very expensive
  • uses positron emitting radioisotope (tracer)
    • fluorine-18
  • gives better contrast and spatial resolution (cf. SPECT)

Single-photon emission computed tomography (SPECT):

  • is lower cost
  • uses gamma emitting radioisotope (tracer):
    • technetium-99m
    • iodine-123
    • iodine-131
  • gives poorer contrast and spatial resolution (cf. PET)