For the first time, researchers at the Massachusetts Institute of Technology (MIT) were able to perform the first laser ultrasound by remotely detecting ultrasound on the surface of the skin.
This is an important development that will go down in the history of medical imaging: the first laser ultrasound images performed remotely, using ultrasound.
Performed by researchers at the prestigious Massachusetts Institute of Technology (MIT), it allows, according to its authors, to obtain an image inside the body, without contact with it and at a distance.
The same results as a conventional ultrasound scan
For many, ultrasound is a safe, painless and non-invasive procedure. It involves pressing an ultrasound probe with gel onto the surface of the skin to generate an image in the desired position. The probe emits sound waves into the tissue and various features such as muscles, fat, blood vessels and bones reflect the sound towards the probe, which records reflected signals and produces an ultrasound image. Because the probe must make contact with the skin surface to transmit and detect ultrasound, the orientation of the probe on the skin surface and the compression of the skin create contact-sensitive images.
For some people, such as infants, trauma or burn victims, or surgical patients, this contact sensitivity can be very poorly tolerated. That is why this alternative approach to ultrasound developed by MIT researchers is so revolutionary.
In an article published in the journal Light Science & Application, they explain that they have developed a new technique that does not require direct contact with the skin surface, as it is able to detect ultrasound at a distance.
In detail, the emission laser sends a pulse of light that is rapidly absorbed by the skin and converted into photo-acoustic sound waves, i.e. the generation of sound by light. The sound waves generated interact with tissues identical to conventional ultrasound and the reflected signals are detected by a laser interferometer on the surface of the skin. Lasers move on the surface of the skin to produce an image.
Successfully tested on humans, this system has shown that laser ultrasound is sensitive to the same tissue characteristics as conventional ultrasound. In addition, it can obtain images at depths in the order of one centimeter, which is much deeper than other optical ultrasound techniques and is comparable to the imaging depths of modern clinical ultrasound.
A promising discovery
For researchers, these first results of laser ultrasound are very encouraging. “We are at the beginning of what we could do with laser ultrasound,” says Dr. Brian W. Anthony, senior scientist at the Mechanical Engineering Department of MIT and the Institute of Medical and Scientific Engineering (IMES). “Imagine getting to a point where we can do everything that ultrasound can do now, but at a distance. It gives you a totally new way to see the organs inside the body and determine the properties of deep tissue, without coming into contact with the patient”.
Now, researchers hope to improve current technology and push laser ultrasound into future clinical use. As the technology progresses, one can imagine designing a laser scanning system capable of capturing images of a patient at a distance without disturbing him or contacting him.