Researchers at the Massachusetts Institute of Technology have revealed the first images of human tissue generated by a new laser ultrasound imaging technology. Unlike traditional ultrasound, new technologies do not require contact with human skin, greatly expanding the range of physicianuse in clinical settings.
Conventional ultrasound is one of the cheapest and easiest imaging methods that clinicians currently use. Unlike X-ray or CT scans, ultrasound does not involve harmful radiation and, unlike PET or MRI scans, does not require large and expensive machines. Of course, ultrasound does have many limitations, from the imaging process to require a large amount of physical exposure to the variability of the imaging results.
A team of researchers at the Massachusetts Institute of Technology has effectively demonstrated a new method of non-contact ultrasound involving lasers. The challenge of developing a new method is to come up with a way to generate sound waves using lasers. Traditional ultrasound uses sound waves to penetrate the human body and bounce back from different tissues. Of course, light doesn’t go as deep into the human body as sound.
The new method has found that pulsed lasers with wavelengths of 1550 nanometers produce sound waves when they hit human skin. A second laser that tracks the same wavelength can then detect reflected sound waves and produce images similar to conventional ultrasound.
Brian Anthony, senior author of the new study, explains: “It’s like we’re walking along a wall, listening in different places, or constantly yelling at the Grand Canyon. Then you’ll get enough data to figure out the geometry of all the objects in which the sound waves bounce. “
In the new study, researchers demonstrated the successful development of this novel laser ultrasound technology, from initial testing of gelatin molds similar to human skin to removal of animal tissue. The study eventually demonstrated the efficacy of the method in human volunteers, showing the first non-contact laser ultrasound images of the human forearm.
At this point, the method cannot provide images at the same resolution as traditional ultrasound techniques, but the researchers believe this is only the first milestone to be reached. The system can potentially be improved to provide more granular organizational detail.
“We’re in the early stages of laser ultrasound,” says Anthony. Imagine that we’ve reached the point where ultrasound can do everything it can, but keep it at a certain distance. This gives you a whole new way to look at the organs in your body and determine the nature of deep tissue without having to make contact with the patient. “
It is this ability to easily generate cheap, detailed images without physical contact that makes this laser ultrasound technology promising. In addition to eliminating inconsistencies that can result from independent operator differences, the non-contact method can also image a large number of patients who are unable to perform traditional ultrasounds. This includes babies, burn victims or post-surgical patients who simply cannot press the probe on the skin.
This eliminates the need for ultrasonic operators and automates processes, as well as allows the use of new portable screening equipment. This suggests a future approach that would provide patients with home screening and maintenance of diseases that would otherwise require regular clinical visits.
“I can imagine a scenario where you can do this at home,” says Anthony. When I get up in the morning, I can get an image of my thyroid gland or artery, and I can perform physiological imaging in my body. You can imagine deploying it in your surroundings to see your internal state. “
The new study is published in the journal Nature, Light: Science and Applications.