Moths' eyes provide inspiration for lower-dose imaging

Taking inspiration from moths' eyes, a team of international researchers has developed a nanoscale material that could improve the light-capturing efficiency of medical imaging devices.

Moths have large compound eyes made up of thousands of tiny structures that form a primitive cornea and lens. Their eyes, however, reflect very little light, helping them to evade predators in the dark. Previous researchers have looked to this model to design more efficient coatings for solar panels and anti-reflective surfaces for military devices, reports Medical Design Technology.

The researchers from two New York City universities, MIT and Shanghai published their work in the journal Optics Letters. They focused on the scintillation materials used in imaging devices that convert the X-rays exiting the body into visible light signals. They sought to increase this light--creating higher image resolution--while reducing the radiation dose patients receive.

They created a thin film, just 500 nanometers thick, covered in crystals of cerium-doped lutetium oxyorthosilicate. These crystals were covered in pyramid-shaped bumps of silicon nitride. Between 100,000 to 200,000 of these bumps fit in a space the size of a moth's eye. Then they made the sides of the device rougher to further diffuse the light.

Adding this film to the scintillator of an X-ray mammographic unit increased the intensity of the emitted light by as much as 175 percent over that of a traditional scintillator, according to

"Our work further improved upon this fascinating structure and demonstrated its use in medical imaging materials, where it promises to achieve lower patient radiation doses, higher-resolution imaging of human organs, and even smaller-scale medical imaging," said Yasha Yi, a professor at the City University of New York.

Yi predicts it will take another three to five years to evaluate and perfect the film, and to test it in imaging devices.

The industry has been working to lower patients' radiation exposure and to develop protocols to "child-size" imaging for the smallest patients. New York's North Shore-Long Island Jewish Health System just spent $12 million to swap out its entire fleet of CT scanners for GE's low-dose models.

Trying another tack, researchers in the Netherlands are experimenting with lasers as an alternative to x-ray mammography.

To learn more:
- read the abstract
- here's the Medical Design Technology report
- check out the article