New X-Ray Technique Targets Tumors and Terror

Robert Cernik and colleagues from the School of Materials at the University of Manchester (UK) have constructed a prototype color three-dimensional (3D) X-ray system that allows substances at each point of an image to be clearly identified. The technique developed by the scientists is known as tomographic energy dispersive diffraction imaging (TEDDI).

The new technique harnesses all the wavelengths present in an X-ray beam to create probing 3D images. The technique improves on existing methods by allowing detailed images to be created with one very simple scanning motion and makes use of a sophisticated detector and collimator engineering developed at Daresbury Laboratory (Cheshire, UK), Rutherford Appleton Laboratory (Swindon, UK), and the University of Cambridge (UK).

Scientists believe this sophisticated engineering will reduce the time taken to create a sample scan from hours to just a few minutes. This shorter period would eliminate the problem of radiation damage, allowing biopsy samples to be evaluated and normal tissue types to be distinguished from abnormal.

Prof. Cernik noted, "We have demonstrated a new prototype X-ray imaging system that has exciting possibilities across a wide range of disciplines including medicine, security scanning, and aerospace engineering. Current imaging systems such as spiral CAT [computed axial tomography] scanners do not use all the information contained in the X-ray beam. We use all the wavelengths present to give a color X-ray image. This extra information can be used to fingerprint the material present at each point in a 3D image. The TEDDI method is highly applicable to biomaterials, with the possibility of specific tissue identification in humans or identifying explosives, cocaine, or heroin in freight. It could also be used in aerospace engineering, to establish whether the alloys in a weld have too much strain.”

To develop the technology, Prof. Cernik and his team have had to overcome two major technologic challenges. The first was to produce pixellated spectroscopy-grade energy sensitive detectors. The second challenge was to build a device known as a 2D collimator, which filters and directs streams of scattered X-rays. The collimator device needed to have a high aspect ratio of 6000:1, meaning that the ratio of its width to its length is more than that of the channel tunnel (Chunnel or Eurotunnel). This device was built using a laser drilling method in collaboration with the University of Cambridge.

Using detectors made from silicon, the Manchester team has been restricted to looking at thin samples or light atom structures. But they are developing new, high purity, high atomic weight, semiconductor detector materials that will remove this difficulty and drastically speed up scanning times. This study was reported in the Journal of the Royal Society Interface, published online November 28, 2007.

A University of Manchester-led project, called HEXITEC, has just started to make new material.


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