New X-ray device images soft tissues

MIT researchers, working with an Indian-origin scientist, have developed a new portable X-ray device that can provide the most detailed images ever - including clear views of soft tissues in detail.
X-rays cannot image the body's soft tissues, except with the use of contrast-enhancing agents that must be swallowed or injected, and their resolution is limited.
The new approach by researchers at Massachusetts Institute of Technology (MIT) and Massachusetts General Hospital (MGH) uses a light-weight portable device to image soft tissue without any need for contrast agents.
The test device the team built, working with Rajiv Gupta of MGH, is about the size of a shoebox. The team expects to spend two to three years refining and improving the design.

While conventional X-ray systems show little or no structure in most soft tissues - including all of the body's major organ systems - the new system would show these in great detail, said Luis Velasquez-Garcia, a principal research scientist at MIT's Microsystems Technology Laboratories.
The new technology could make X-rays ubiquitous, because of its higher resolution, the fact that the dose would be smaller and the hardware smaller, cheaper, and more capable than current X-rays, said Velasquez-Garcia.

The key in the new system is to produce coherent beams of X-rays from an array of micron-sized point sources, instead of a spread from a single, large point as in conventional systems, he explained.

The team's approach includes developing hardware that is an innovative application of batch microfabrication processes used to make microchips for computers and electronic devices.
Using these methods - alternating between depositing layers of material and selectively etching the material away - the MIT researchers have produced a nanostructured surface with an array of tiny tips, each of which can emit a beam of electrons.
These, in turn, pass through a microstructured plate that emits a beam of X-rays.
Using the first version of the cathode, the team was able to capture high-resolution absorption images of samples where fine soft-tissue structures are clearly visible.

Since the new system is electronic - today's thermionic systems take time to heat up - it can be switched on and off much faster, resulting in a much lower dose of radiation to the patient, Velasquez-Garcia said.
The new system could also be useful in airport screening of baggage, where its ability to distinguish among liquids could make it much easier for agents to differentiate a harmless bottle of shampoo from a container of explosive material or a hazardous chemical, researchers said.