Which imaging technique uses gamma cameras to produce three-dimensional images of tissue perfusion?

• A. Angiography
• B. MRI
• C. Single Photon Emission Computed Tomography
• D. EEG

Answer: (C)

SPECT uses gamma cameras to create three-dimensional images of tissue perfusion by tracking a radiotracer distributed in the body. A radiopharmaceutical emits gamma rays from within tissues where it concentrates according to blood flow. Gamma cameras positioned around the patient pick up these photons from multiple angles. The data are then reconstructed into a 3D map showing where the tracer—and thus perfusion—is highest or lowest. This functional imaging approach is especially useful for assessing blood flow to the heart or brain. Other techniques either visualize anatomy of vessels with contrast (angiography), rely on magnetic fields to image tissue (MRI), or measure electrical activity on the scalp (EEG), rather than using gamma cameras to map tissue perfusion.