A New Laser-Based System Can Look Inside Your Body Without You Knowing

MIT engineers have created a new way of medical imaging that is neither invasive nor hands-on the patient. They can now use lasers to scan beneath the patient's skin without needing physical contact, which improves beyond the limitations of ultrasound as other currently used machines.

Right now, medical professionals and physicians can rely on a lot of machines and techniques for looking inside the human body before having to use surgery; however, those techniques have their own pros and cons. Using X-ray repeatedly can leave patients with damages from radiation while using CT scans involve the patient lying motionless in an uncomfortable environment. And while ultrasound seems to be the simplest approach, it includes a soundwave-emitting wand pressed against the patient’s skin, making it useless in certain circumstances like a patient with severe burns.

The engineers at MIT explained in a paper published last week about how they came up with a system mimicking an ultrasound machine’s capabilities, which uses lasers from up to 50 centimeters away from the patient. To make the laser suitable for this task, the researchers decided to use a 1,550-nanometer wavelength, which can be absorbed by water but safe enough for the eye and skin.

Water is the largest component of skin, so when the laser is pointed at the patient, the skin absorbs it and the laser heats up gently, hence the water in the skin expands. That expansion and contraction can be controlled through pulsing the laser beam, which creates a steady oscillation that produces soundwaves. Then, these soundwaves propagate through the human body similar to the soundwaves from the wand of an ultrasound machine.

However, the engineers at MIT didn’t use a microphone for detecting how the soundwaves bounce off the internals of the human body, they instead used a second laser as a sensitive motion detector. With each type of tissue, the soundwaves interact with different frequencies and intensities as they travel through the body, creating vibrations on the skin’s surface that can be detected as well as measured. Then, these measurements are processed with algorithms and software, generating an image of the inside of the human body.

For now, this laser-based system can image a patient to six centimeters deep below the skin. It hasn’t matched the capabilities of traditional ultrasound techniques yet, but when testing on animal tissue and human subjects, the researchers found that the lasers could distinguish subtle features like the differences between muscle, fat deposits, and bone.

The research team is also looking to improve the system’s capabilities, including enhancing the resolution for finer tissue imaging and reducing the size fo the hardware so that it can be a portable system. Since the system doesn’t require physical contact, it can be used by those without intensive training, meaning we can perform the procedure at home on a daily routine.

However, this approach also means that a person can be examined without them knowing. So, it seems that the approach has already had its own pros and cons, but along with further development and fineness of the system, let’s hope that the researchers will come up with proper ways to use it too.