Functional Brain Imaging in Psychiatric Disorders – One Minute Medical School

Measuring blood flow through the brain can tell us which neurons are working hard and which are underperforming, because hard working neurons demand more blood supply than idle neurons. Single-photon emission computed tomography (SPECT) is one tool we use to create 3D maps of brain activity.  See how it works and how we use it to investigate psychiatric disorders.

3 Replies to “Functional Brain Imaging in Psychiatric Disorders – One Minute Medical School”

  1. GREAT video! I would love to see the same premise (necessity for SPECT to determine subtypes and co-morbidities) explained for more psychiatric disorders! My child received an ADHD diagnosis and was put on stimulant medication, with disastrous results–intensified anxiety and pulling his hair out. With the help of SPECT imaging, we found that his brain showed not only ADD patterns (low PFC activity), but bipolar (ring of overactivity) as well. SPECT, along with forward-thinking psychiatrists, helped us find a better treatment plan that is NOT doing harm.

  2. What are the possible long-term implications for using somewhat invasive techniques on the developing CNS of children? Also, I am curious to know the half-life and toxicity levels of the isotope used in SPECT. I just cannot imagine using imaging techniques for routine analysis and diagnosis.

    1. Sorry, I totally missed this! The possible long-term implications. I assume by this you mean the carcinogenic potential? So low as to be unmeasurable. Nuclear medicine procedures have been, and are, performed safely in children around the world, for numerous indications. For instance, when we treat Grave’s Disease in children, we use doses of I-131, a beta emitter. Of the 10 milliCurie activity, typically 50% of this will accumulate in the 40 grams of thyroid tissue, with a half-life of 8 days, delivering a radiation dose >100 Gray to the thyroid. This has, in the 50 years we’ve been keeping records, not been shown to lead to any increase in cancer risk. Of the 10 mCi of technetium-99m in the brain tracer dose, only 5% accumulates in the brain, a much larger organ, and the half-life is 6 hours. Total dose of radiation to the brain is therefore much smaller: 10 milliGray, or 0.01 Gray. By comparison, average background radiation is about 3 mGy per year. According to the American Academy of Science BEIR (Biological Effects of Ionizing Radiation) Committee, the minimum dose of radiation before even a minimally statistically significant difference in cancer rates can be detected between exposed individuals and the general public is 100 mSv (100 mGy equivalent in gamma radiation).

Leave a Reply