How Does SPECT Differ from Other Brain Scans?

Thanks to advancements in medical imaging, there are numerous ways to see inside the human body. Imaging has significantly improved the diagnosis and treatment of many medical conditions. Even better, one study found that medical imaging is directly linked to an increase in longevity.

Despite the widespread use of medical imaging for physical conditions such as cancer, heart disease, and fractures, it remains underutilized in the mental health field. Psychiatry remains the only medical specialty that rarely looks at the organ it treats—the brain.

This is beginning to change, however.

But which brain-imaging tools are best when it comes to evaluating brain function as it relates to behavior and neuropsychiatric issues?

In this blog, you’ll discover the basic differences between SPECT scans, PET scans, MRI scans, and fMRI scans.

Despite the widespread use of medical imaging for physical conditions such as cancer, heart disease, and fractures, it remains underutilized in the mental health field. This is beginning to change, however. Click To Tweet


What is a SPECT scan?

Single photon emission computed tomography (SPECT) is a nuclear medicine study that measures blood flow and activity in the brain. A single SPECT scan can show blood flow and activity across the entire brain.

Often used in research, SPECT is becoming more commonly used in clinical psychiatric practice. Compared to other functional brain-imaging methods, SPECT is typically the most affordable.

Over the past 30-plus years, Amen Clinics has built the world’s largest database of brain scans related to behavior with over 225,000 brain SPECT scans. Based on this groundbreaking work, as well as decades of research on brain SPECT imaging, a growing number of mental health providers are recommending brain imaging as part of a complete evaluation.

What do SPECT scans show?

SPECT scans show how the brain functions and reveal areas of the brain with healthy activity, too much activity, or too little activity.

Healthy Brain SPECT Surface Scan


Low Blood Flow on Brain SPECT Surface Scan 


Healthy Brain SPECT Active Scan


Overactivity on Brain SPECT Active Scan


In 2021, the Canadian Association of Nuclear Medicine (CANM) unanimously adopted new procedure guidelines for SPECT imaging for psychiatry and neurology. CANM endorsed brain SPECT imaging for the evaluation of several common conditions that impact millions of individuals, such as:

Based on findings from the Amen Clinics database of functional brain scans related to behavior, SPECT has also shown to be useful in the evaluation of:

Among SPECT’s many benefits, it averages brain activity levels over a few minutes, making it ideal for evaluating brain function during everyday activities, such as concentrating, meditating, and reading.

Some of the additional ways SPECT can help people with mental health disorders include:

  • Decreasing shame and stigma: Seeing that a “mental” health condition is actually a brain-based issue helps people see their problems as medical, not moral.
  • Improving compliance: Seeing that problems are biological encourages people to stick with a treatment plan.
  • Breaking denial: Seeing abnormal brain activity helps individuals stop denying that they have a problem. This can be especially powerful for people with substance use disorders or addictions.
  • Helping prevent treatment mistakes: When used in conjunction with a full psychiatric evaluation, seeing the brain helps psychiatrists make more effective treatment recommendations.
  • Offering hope that you can change your brain: Seeing before-and-after SPECT scans of patients who have optimized their brain function and improved their symptoms gives hope that you can do it too.


What is an MRI scan?

Magnetic resonance imaging (MRI) uses a strong magnetic field and radio waves to view parts of the brain. MRI produces images of the brain’s structure.

What do MRI scans show?

The 3-D pictures produced can show problems in the anatomical structure of the brain or brain stem, such as:

  • Tumors
  • Cysts
  • Blood vessel problems
  • Inflammation
  • Swelling
  • Infections

MRI does not give any information on brain function, which limits its effectiveness in providing useful information on conditions involving behavior or emotions. In addition, MRI scanners can feel claustrophobic and are very noisy, which causes anxiety for some people.


What is an fMRI scan?

Functional MRI, or fMRI, is a type of MRI that measures blood flow and brain activity. The fMRI is a very expensive tool that has become popular for scientific research but is not as commonly used in clinical settings.

What do fMRI scans show?

fMRI shows neural activity in real time, showing how the brain responds to various stimuli. For example, depending on which brain functions are being evaluated, a person will be asked to perform certain tasks. These tasks may include viewing pictures, reading, playing word games, or listening to audio files.

Performing these tasks will cause increased activity and blood flow in certain brain regions. The fMRI machine captures the heightened activity in the images it produces.

One drawback of using fMRI to evaluate the brain is that it only takes images of one particular brain region at a time. Depending on your symptoms, multiple scans may be required. This can be time-consuming and expensive.

Another downside of fMRI is that like an MRI, the procedure can be uncomfortable and loud and can make people feel anxious.


What is a PET scan?

PET (positron emission tomography) is a nuclear imaging technology that is similar to SPECT in that it is a functional brain scan. Like SPECT, PET scans show areas of the brain with healthy activity, overactivity, and underactivity.

What are the basic differences between SPECT and PET scans? Importantly, PET scans are far more expensive than SPECT scans.

In addition, with PET scans, the brain images are taken while an individual is lying in the camera. Many people find this to be noisy and unpleasant, which can be anxiety provoking.

With SPECT, the images occur while a person is in the injection room. This increases reliability and makes the procedure easier to perform.

What do PET scans show?

Like SPECT, PET scans allow healthcare professionals to view how the brain functions. PET measures blood flow and glucose metabolism in the brain.

PET scans are often used to investigate:

  • Cancerous brain tumors, or to see if cancer elsewhere in the body has spread to the brain
  • Epilepsy
  • Alzheimer’s disease and other dementias
  • Neurodegenerative diseases, such as Parkinson’s disease and Huntington’s disease
  • Stroke
  • Traumatic brain injuries
  • Movement disorders such as Parkinson’s disease
  • Abnormalities in neurotransmitter systems
  • Neuropsychiatric disorders


If you’re struggling with mental health issues or memory loss that isn’t responding to standard treatments, it’s time to consider brain imaging. Based on costs, availability in the psychiatric clinical setting, reliability, comfort, convenience, and research, brain SPECT imaging checks the most boxes.

Functional brain imaging with SPECT helps psychiatrists ask better questions to get to the root causes of your problems. This leads to more accurate diagnoses and more effective treatment plans.

Over the past 30-plus years, Amen Clinics has used SPECT to scan people across the globe from 9 months old to 105 years old. And it has helped them with a wide variety of mental health disorders and other cognitive issues. With this experience, as well as more than 80 peer-reviewed scientific studies on SPECT published, Amen Clinics has emerged as the world leader for brain SPECT imaging in the mental health field.

Depression, anxiety, ADD/ADHD, memory loss, and other mental health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, clinical evaluations, and therapy for adults, teens, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.

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