When doctors assess the inflammatory skin disease psoriasis, they generally do so via a visual examination of the red, scaly patches on the skin's surface. This can be subjective, however, plus it doesn't take into account what's going on at a deeper level. That's why German scientists from Helmholtz Zentrum München and the Technical University of Munich have developed a handheld scanner that looks beneath the skin – and it doesn't expose the patient to any harmful radiation.

Known as RSOM (raster-scan optoacoustic mesoscopy), the technology incorporates weak laser pulses that are used to slightly heat the tissue being examined. This causes the tissue to momentarily expand, which in turn generates ultrasound waves. The sensor is able to detect those waves, and analyzes them to create a high-resolution image of what's happening under the skin.

In lab tests performed on psoriasis patients, RSOM allowed the scientists to determine individuals' skin thickness, capillary density, number of blood vessels, and total blood volume in the skin. Down the road, it's possible that the system could also be used to assess diseases such as skin cancer or diabetes.

"This technology, which is easy to use and does not involve any radiation exposure or contrast agent, is allowing us to acquire the first new insights into the disease mechanisms," says Prof. Dr. Vasilis Ntziachristos, Director of the Institute of Biological and Medical Imaging at the Helmholtz Zentrum München, and Chair of Biological Imaging at the Technical University of Munich. "It also facilitates treatment decisions for the physicians."

A paper on the research was recently published in the journal Nature Biomedical Engineering.