Table of Contents
Replacing traditional ultrasound imaging
Conventional ultrasound imaging has been substituted by a laser technology alternative that does not require physical contact and can be used on patients who cannot tolerate a probe on their skin, such as burn victims, individuals with sensitive skin, and infants. Tissue imaging has been conducted safely using a remote laser system aimed from half a meter. The laser technology was tested on the forearms of volunteers, resulting in high-quality images, comparable to the standard ultrasound, where common tissue features, such as muscle, fat, and bone, down to about 5 cm below the skin, were observable.
Challenges of laser-based imaging
Sound waves can penetrate further into the body than light; therefore, the primary challenge is converting a laser beam’s light into sound waves at the skin’s surface to visualize deeper within the body. 1550-nm lasers are used for tests because a laser beam wavelength is absorbed by water and is safe for the eye and skin with large safety margins.
Human skin consists largely of water, so researchers confirm that it should ideally absorb the wavelength of 1550-nm lasers and that it would heat up and expand in response. Then it is expected that the skin creates sound waves that spread through the body as the laser system’s wavelength returns to its standard state.
Dual-laser setup for imaging
One pulsed laser at 1550 nm that emits sound waves, and a second continuous laser system that remotely detects reflected sound waves, are used to test the idea. This second laser acts as a motion detector, allowing the measurement of vibrations at the skin surface. Skin surface motion, in its turn, changes the laser beam’s frequency. The 1550-nm laser system enables obtaining data at various points and creates an image of the region.
Testing and results
The first tests of the developed laser system include imaging of metal components installed in gelatin (similar to water in skin), imaging of animal tissues, and then experiments in humans. Ultrasound scanning of forearms helps to develop the first fully non-contact laser system for safe tissue imaging. Additionally, the 1550-nm laser system allows a clear distinction of the fat, muscle, and tissue boundaries.
It is planned to improve the laser technology by increasing the laser system’s performance. Moreover, the researchers plan to update the detection laser beam’s abilities as well as to miniaturize the laser system setup up resulting in the manufacture of a portable imaging device that may be used at home.