LEDs and Medicine: Diffuse Optical Tomography Uses LEDs to Scan Brain

A look at current DOT testing

A look at current DOT testing

According to a report in BioOptics World, scientists at the Washington School of Medicine in St. Louis, Missouri have developed a new way to study the brain, diffuse optical tomography (DOT), a new non-invasive technique that relies on LEDs rather than magnets or radiation. While still experimental, it offers promise for a new non-invasive test for the human brain.

While it looks primitive now, DOT scans use LED light to measure brain activity. For a DOT scan, a subject wears a cap composed of many light sources and sensors connected to cables. A DOT cap covers two-thirds of the head and involves shining LED lights directly into the head. DOT images show brain processes taking place in multiple regions and brain networks, like those involved in language processing and self-reflection (daydreaming). It also avoids radiation exposure and bulky magnets required by positron emission tomography (PET) and magnetic resonance imaging (MRI) respectively.

DOT works best for patients with electronic implants that can be problematic with MRI testing such as pacemakers, cochlear implants, and deep brain stimulators (used to treat Parkinson’s disease). The magnetic fields in MRI may disrupt either the function or safety of implanted electrical devices while DOT doesn’t impact these types of devices.

How does DOT work? According to author Joseph Culver, Ph.D., associate professor of radiology, DOT can detect the movement of highly oxygenated blood flows to the parts of the brain that are working harder when the neuronal activity of a region in the brain increases. He told BioOptics World that, “It’s roughly akin to spotting the rush of blood to someone’s cheeks when they blush.”  According to the magazine, DOT works by detecting light transmitted through the head and capturing the dynamic changes in the colors of the brain tissue.

DOT has a lot of potential benefits for medicine concerning the brain.  Since DOT technology does not use radiation, doctors could monitor progress of patients using multiple scans performed over time without worry. It could be useful for patients recovering from brain injuries, patients with developmental disorders such as autism, and patients with neurodegenerative disorders such as Parkinson’s.

Currently, a full-scale DOT unit takes up an area slightly larger than a phone booth, but Culver and his team have built versions of the scanner mounted on wheeled carts. The DOT device is designed to be portable, so it could be used at a patient’s bedside in the hospital or at home, in a doctor’s office, or even in the operating room in the future.

For more details about DOT, visit:

BioOptics World, DIFFUSE OPTICAL TOMOGRAPHY ABLE TO SCAN THE BRAIN WITHOUT RADIATION, MAGNETS, http://www.bioopticsworld.com/articles/2014/05/diffuse-optical-tomography-able-to-scan-the-brain-without-radiation-magnets.html

Nature, Mapping distributed brain function and networks with diffuse optical tomography, http://www.nature.com/nphoton/journal/v8/n6/full/nphoton.2014.107.html (registration required)