Traditional medical imaging — used to diagnose, monitor or treat certain medical conditions — has long struggled to obtain clear images of dark-skinned patients, experts say.
Researchers say they have found a way to improve medical imaging, a process by which doctors can look inside the body, regardless of skin color.
The new findings were published in the October edition of the journal Photoacoustics. The team tested the forearms of 18 volunteers, with skin tones ranging from light to dark. They found that a distortion of the photoacoustic signal that makes imagery harder to read, called clutter, increased with darkness of the skin.
“When you have darker skin, you have more melanin. And melanin is actually one of the optical absorbers that we inherently have in our body,” Muyinatu Bell, study author and director and founder of the Photoacoustic and Ultrasonic Systems Engineering (PULSE) Laboratory, told CNN from JHU. In other words, the amount of melanin in the skin could be associated with more bulk.
“The skin basically acts as a sound transmitter, but it’s not the same type of focused sound that we get and want with ultrasound, it’s broadcast everywhere and creates a lot of confusion,” Bell said . “And so this diffusion of sound caused by melanin absorption is worse and worse with the higher melanin concentration.”
The study – a collaboration with Brazilian researchers who had previously used one of Bell’s algorithms – found that the signal-to-noise ratio, a scientific measure that compares the signal to the background noise, improved for all skin tones when researchers used a technique called “short-offset spatial coherence beamforming” when performing medical imaging. This technique, initially used for ultrasound, can be applied to photoacoustic imaging.
The technique involves a combination of light and ultrasound technology, forming a new medical imaging modality, Theo Pavan, study author and associate professor in the physics department at the University of São Paulo, told CNN. Brazil.
“We really verified that it was much less sensitive to skin color in terms of the quality of the image that you can get compared to conventional methods that… are more commonly used by the community,” Pavan said.
The study is “the first to objectively assess skin tone and demonstrate qualitatively and quantitatively that skin ‘photoacoustic signal’ and clutter artifacts increase with epidermal melanin content,” the researchers wrote.
Applications of photoacoustic technology vary, but thanks to new developments by researchers, it could help diagnose health problems more accurately and fairly.
“At present, the applications of breast imaging are increasing,” and the next step would be “to increase the overall quality of the image,” said Guilherme Fernandes, author of the study and holder of a Ph.D. candidate in physics applied to medicine and biology at USP.
The researchers’ work could also mean advances in equity in health care generally.
“In our scientific technology, there is a bias in terms of developing these products, for products that work well in people with lighter skin,” said Dr. Camara Jones, a family physician, epidemiologist and former president of the American Public Health Association. who was not involved in the new study.
“The biggest problem is that we use what we call race as a risk factor – as a health risk factor. Race therefore is the social interpretation and interpretation of people’s appearance in a race-conscious society. Race is not biology,” Jones explained. “We have mapped the human genome. We know that there is no basis in the human genome for racial subspeciation.
This study is not the first to uncover skin color bias in medical technology. It has also been found that medical equipment using infrared sensing does not work as well on darker skin tones because skin tone can interfere with light reflection.
Many devices frequently used during the Covid-19 pandemic, such as pulse oximeters and forehead thermometers, involve emitting and capturing light to make a measurement. But if this device isn’t calibrated for darker skin, pigmentation could affect how light is absorbed and how infrared technology works.
Bell said his research could hopefully lead the way in eliminating discrimination in health care and inspire others to develop technology that helps everyone, regardless of the color of their skin .
“I believe that with the ability to show that we can design and develop technology, it doesn’t just work for a small subset of the population, but works for a broader spectrum of the population. This is very inspiring not only for my group, but also for groups around the world who are starting to think in this direction when designing technologies. Does this serve the population at large? » said Bell.