What is SPECT

SPECT stands for single-photon emission computed tomography. It is an imaging technique that shows blood flow in tissues and organs. This test uses a radioactive substance (around 0.68 radiation exposure, compared to 0.90 rem from a head CT scan) that is injected into the bloodstream to show how well blood is flowing in that area. The old president of the Society of Nuclear Medicine, Michael Devous, Ph.D., wrote, “SPECT […] procedures have no more risk than MRI-based procedures[…]. Indeed, there are no data demonstrating harm to humans by radiation exposure at diagnostic imaging levels”. The radioactive trance produces gamma rays that are picked up by a gamma camera. The SPECT scan produces 3D images of the area being examined.

SPECT was developed more than 50 years ago. Brain scans using SPECT are normally used to look at Alzheimer’s Disease, seizures, strokes, head trauma, chemical exposure, Lyme disease, brain inflammation, and drug toxicity.

(Image from https://www.braingymmer.com/en/blog/SPECT_imaging/ )

A “surface view” shows areas with low activity in the brain. A healthy surface view scan should show a “full” brain with symmetrical activity. An “active view” shows active areas. In a healthy brain scan, the most active area of the brain is the cerebellum (Amen 2021).

(Both images are from the Amen Clinics Website: https://www.amenclinics.com/approach/why-spect/)

References:

Amen DG, Easton M. A New Way Forward: How Brain SPECT Imaging Can Improve Outcomes and Transform Mental Health Care Into Brain Health Care. Front Psychiatry. 2021 Dec 10;12:715315. doi: 10.3389/fpsyt.2021.715315. PMID: 34955905; PMCID: PMC8702964.