Mathematicians Attempt To Improve Medical Scans

Mathematicians have found that it is possible to gain full control of sound waves, which could lead to improved medical scans for technology such as ultrasound machines.

Working in partnership with the Indian Institute of Technology Kanpur (India), mathematicians from the University of Liverpool (UK) evaluated the numerical characteristics of a flat lens made out of ‘meta-material'--a substance that gains its properties from its structure rather than its composition. This material is thought to defy the laws of physics, allowing objects to appear exactly as they are rather than upside down as seen in a normal convex or concave lens.

Dr. Sebastien Guenneau, from University of Liverpool's department of mathematical sciences, explained, "We know that light can be controlled using 'meta-material,' which can bend electromagnetic radiation around an area of space, making any object within it appear invisible. Now we have produced a mathematical model that proves this theory also works for sound. This theory becomes particularly interesting when considering ultrasound, which is a sound pressure used to penetrate an object to help produce an image of what the object looks like inside. This is most commonly used in pregnancy scans to produce an image of a fetus. We found that at a particular wave frequency the meta-material has a negative refraction effect, which means that the image produced in the flat lens appears at a high resolution in exactly the same way it appears in reality.”

What surprised the researchers most of all, however, was at the point where negative refraction occurs the meta-material becomes invisible, suggesting that if they were to utilize this in sonogram technology, it could be possible to make the image appear in mid-air like a hologram instead of on a computer screen. They also discovered that if the meta-material was positioned in a checkerboard manner, sound became trapped, making noisy machines, for example, quieter, according to Dr. Guenneau.

The scientists predicted that the technology could be modified for tests at higher sound frequencies such as when drilling for oil, where a more accurate image of the earth could be made to locate where drilling should take place.


Related Links:
University of Liverpool
Institute of Technology Kanpur