Brain SPECT Imaging
A brain SPECT scan shows how different areas of the brain are functioning. Here's what the scan is, how it works, what to expect, and how to prepare.
Why look at the brain?
Most psychiatric care is built on what can be seen and heard: the symptoms you describe, your history, and how you respond to treatment. For many people, that's enough to find the right path. Others try medication after medication and still don't feel like themselves.
When that happens, it can help to look more closely. A brain SPECT scan shows how blood flow and activity vary across different areas of the brain. It doesn't diagnose a condition on its own, and it doesn't replace a careful evaluation. What it adds is another layer of information that Dr. Chakra reviews alongside your history, your symptoms, and the rest of your life, like sleep, stress, nutrition, and physical health.
What is a brain SPECT scan?
A brain SPECT scan is an imaging test that looks at blood flow and activity patterns in the brain. An MRI or CT scan mainly shows the brain's physical structure. A SPECT scan adds information about how different areas of the brain are functioning.
SPECT stands for Single Photon Emission Computed Tomography. In plain terms, the scan shows which areas of the brain have expected activity, relatively higher activity, or relatively lower activity.
A SPECT scan is one piece of a larger evaluation. Results are considered together with your symptoms, medical history, clinical evaluation, and any other relevant testing. The scan is not used on its own to make a psychiatric diagnosis.
SPECT is also well established in neurology for a number of indications, including evaluating cerebrovascular disease, suspected dementia, localizing seizure activity, and assessing traumatic brain injury.
How it works
A small IV is placed in your arm, and an imaging solution containing a very small amount of radioactive tracer is injected. Within minutes, the tracer is absorbed by brain cells based on the amount of blood flowing to each area. This creates a snapshot of how different parts of your brain are functioning at that moment.
After the tracer has tagged your blood, you'll lie on an imaging table while special cameras slowly rotate around your head. The cameras detect the tracer and use that information to create detailed images showing patterns of blood flow and activity throughout your brain.
The scan itself takes about 20 minutes, and you do not have to go inside a tube.
Who might consider a SPECT scan?
It is worth a conversation for patients in situations like these:
- Complex presentations where symptoms do not fit neatly into one diagnosis
- Cases where multiple treatments have been tried without much result
- A history of head injury or concussion where the effects are unclear
- Situations where a physical or neurological factor may be contributing and needs to be considered
How does Dr. Amar Chakra use SPECT?
As one source of information alongside clinical evaluation.
In complex cases, imaging can surface something that reframes the question. Dr. Chakra has described cases where a scan pointed toward brain regions involved in behaviors that had previously been attributed entirely to ADHD, which changed how he approached the treatment plan.
Information from a scan gets weighed alongside everything else: history, symptoms, physical health, what has already been tried, and what has not worked. It is additive to the clinical picture.
What to expect: the concentration scan
A concentration SPECT scan captures how your brain works while you are actively focusing. The tracer is given during a concentration task, so the images reflect your brain at work rather than at rest.
Here's how the appointment goes:
- A small IV is placed in your arm.
- You complete a computerized attention and concentration task, which takes about 15 to 20 minutes.
- While you are working on the task, the tracer is given through the IV.
- After the tracer is absorbed, you lie on the scanning table while the images are taken. This part takes about 20 minutes.
The full appointment runs longer than the 20 minutes of imaging, since it also includes preparation, the IV, the concentration task, and getting set up on the table.
The scanner is more open than a traditional MRI. You lie on a table while cameras rotate around your head, not inside a long tube. The main thing asked of you is to stay still while the images are collected.
How to prepare for your scan
Following these instructions helps your scan come out as accurate as possible.
Medications
Stop stimulant medications 4 days before your scan. Keep taking all other medications unless your prescribing clinician tells you otherwise. Please don't stop or change any other medication on your own.
Caffeine
No caffeine on the day of your scan. That includes coffee, tea, energy drinks, caffeinated sodas, and any other caffeinated drink or product.
Food and water
Eat normally earlier in the day, then stop eating 1 hour before your appointment. Water is fine and encouraged up until 1 hour before your scan.
What about radiation?
A SPECT scan uses a small amount of a radioactive tracer called Technetium-99m, so it does involve some radiation exposure. The scanner itself doesn't give off radiation. It only detects the small amount coming from the tracer, which is where the exposure comes from. The average radiation exposure for one SPECT scan is 0.7 rem, which is similar to the amount from a nuclear bone scan or a CT scan. A course of care involves a single scan.
The tracer has a half-life of just over 6 hours. Because it is not an iodine-based dye, people typically do not have allergic responses to it.
Because of that exposure, the scan is used selectively rather than routinely, and radiation is part of the conversation with Dr. Chakra before a scan is scheduled. If you are pregnant, might be pregnant, or are breastfeeding, please tell us before scheduling.
Frequently asked questions
Questions about whether imaging fits your situation?
Start with an evaluation and you can talk it through with Dr. Amar Chakra directly.