​Color X-Rays Are Coming

Given that they're pictures of bones, it may never have occurred to you that X-rays are actually in black and white, but they are—for now, anyway. The University of Canterbury in New Zealand announced Thursdaythat they are planning to build the "first full-spectral CT colour X-ray scanner designed for human clinical trials."

The country's science and innovation minister, Steven Joyce, announced that a $12 million government grant will be allotted to the university to build a full-color CT scanner that will be used to look at heart disease and bone implants such as hip replacements, as well as to help cancer researchers and drug developers.

"The scanner will be built by the University of Canterbury and when ready will be hosted by the Otago Medical School in Christchurch in the heart of the Christchurch health precinct," associate professor Anthony Butler said in the announcement. "Lincoln University will provide large animals for testing."

The mention of "large animals" may tip you off that researchers, at Canterbury and elsewhere, have already been using small color X-rays on small animals. The Canterbury scanner will be tested on large objects within three to four years, and on humans in six, Butler said.

It's pretty easy to explain a color X-ray machine. Just as color film measures the red, blue, and yellow wavelengths of light in the frame, a color CT scan looks out for different wavelengths, but instead of the spectrum of white light, it measures how specific energies of X-rays—waves outside those visible to the human eye—are attenuated as they pass through an object.

Thanks to differences in atomic structure, all materials attenuate the wavelengths differently, which allows things like bone and a contrasting agent like iodine to appear as different colors. Different densities are also visible, and CT scans already do three dimensions.

Robert Cernik, a materials scientist at Manchester University in the UK, was working on full-spectrum CT imaging back in 2007, and described the advantages it would bring to New Scientist.

"If you were looking for abnormal tissue, you would know the particular diffraction 'fingerprint' you were looking for," Cernik said. On top of medical applications, he alluded to the potential for studying metals: "The pattern can also measure changes in the crystal structure of materials like aluminum, for example, to look at the strain in a weld."

No one had to make a case for color TV, or Game Boy Color, so it's not like you really have to find a justification for color x-rays. But aside from the research benefits gleaned from the enhanced images, a little color could really dress the white walls of the doctor's offices up.

Inset image: MARS Medipix All Resolution System