Bioengineering, Medicine team up on laser dermatology breakthrough
Have a particularly problematic tattoo you want to get rid of? Looking to get rid of troublesome body hair? Removing both requires getting laser light deep into the skin, past the protective layer of melanin.
Currently, the process requires high powered lasers to get through the top, protective layer of skin deeper into the tissue, and relies on free-space propagation of the laser beam (i.e., through the air), which can be dangerous both to the clinician and the patient. Stray laser beams can cause permanent eye damage at the power needed to affect tattoo removal. But new technology developed by University of Missouri College of Engineering researchers in collaboration with the MU School of Medicine is primed to make the process safer and more effective.
Mizzou Engineering doctoral candidate Paul J.D. Whiteside and Assistant Professor of Bioengineering Heather K. Hunt are using a technique, invented in the Hunt Lab, called sonoillumination to allow the laser to penetrate deeper into the skin with greater efficiency. Moreover, instead of free-space propagation, the laser transmits directly into the skin only on contact. This means lower-powered lasers can achieve the same results, providing greater health and safety benefits both for the patient and the dermatologist performing the procedure.
Whiteside was part of a research team that invented what’s called a “selective-release waveguide.” This device allowed users to transmit laser light directly into the skin through physical contact of the waveguide with the tissue, and only through the portion of the device touching the skin. Instead of having to aim and risking potentially eye-damaging reflections, dermatologists could be more accurate since the laser was emitted only when in contact with the skin surface.
“Optical fibers, like Google Fiber uses for telecommunications, are examples of optical waveguides, because the light enters one end and is confined along the length of the fiber until it transmits out the other end,” Whiteside said. “Our waveguides were unique in that we didn’t transmit out the other end of the material, but instead transmitted exclusively through the portion of the waveguide that was touching the skin. Using these waveguides, it was possible to eliminate the possibility of hazardous reflections during laser dermatology procedures.”
Through years of research into waveguides and potential applications, Whiteside and his colleagues began using them for ultrasonic imaging purposes. Once they realized the waveguides could both generate and detect laser-induced ultrasonic waves, they realized the effect could be reversed, pairing an ultrasonic device with a waveguide to improve laser dermatology. That’s when Hunt, Whiteside, and their research team paired up with Nicholas Golda, director of dermatologic surgery at University of Missouri Health Care and an associate professor of dermatology at the MU School of Medicine, to begin moving the process forward in the clinical realm.
The process works because the ultrasound modifies the optical properties of the top, protective layer of skin, allowing the laser to get to the deeper levels of tissue where the ink or hair roots reside, instead of being absorbed by the skin. To use an analogy, the ultrasound peels back the curtain so the laser can perform the show.
Current methods require high-powered lasers in order to get through that layer of skin, and the more melanin one’s skin contains, the more energy the laser needs to penetrate to the target areas. These procedures can be incredibly irritating or painful to the patient’s skin because of the strength of the laser.
If the sonoillumination technology becomes commonplace in the next few years as hoped, dermatologists can use lower-powered lasers to achieve the same results. The technology also has the potential to open up such procedures to a wider group of people, as they’re currently more difficult and more painful for patients with darker skin.
“Usually your skin ends up really, really red and can end up really raw, depending on what your skin pigmentation is. The darker your skin is the more likely you are to have side effects. You can essentially lower it down and have the same effectiveness you have currently, but with fewer side effects,” Hunt said.
This research breakthrough was the centerpiece of Whiteside’s recent presentation at the American Society for Laser Medicine and Surgery Annual Conference in San Diego, and a paper about the process titled “Ultrasonic modulation of tissue optical properties to increase transdermal light transmission,” was recently published by the ASLMS. Funding for the project came from the UM System Fast Track Program and ASLMS.