/ 3 October 2007

Diagnostic imaging is here

The practice of modern medicine is a far cry from the staid old family physician with the white coat. In fact, doctors wearing white coats these days are the exception, not the rule.

Even hospital doctors are more relaxed these days — and portray this to their patients, with positive psychological effects. Technology has had a hand in this and today, as opposed to the past, most things are measurable, detectable, imageable.

In the past few years the University of Cape Town and Groote Schuur Hospital — with the Red Cross Children’s Hospital — have been the backdrop for the development of the latest in hi-tech equipment used for, among other things, the detection of tuberculosis (TB) in children and other specialised applications.

This low-dose X-ray machine, which uses slot scanning digital X-ray technology to create high-resolution images, is used in the emergency room.

This machine, developed by a proudly South African SMME called Lodox Systems, was conceived, designed and manufactured locally with the input of researchers in the hospitals and funding from the Technology and Human Resources for Industry Programme.

The development is continuing under the leadership of Professor Kit Vaughan at the University of Cape Town. Statscan machines manufactured by Lodox Systems are being marketed already in the United States, Middle East, Europe and Africa.

Its pioneering record is all the more impressive, taking into account the fact that neither in the US nor in Europe does a digital image processor exist with these attributes.

Vaughan says the aim of the research is to develop algorithms, software solutions and working prototypes for low-dosage, slot-scanning digital X-ray devices for the medical industry — all done on South African soil and creating job opportunities for technical people of the highest calibre.

So far the research project has developed an innovative technique to correct for aspect ratio in slot scanning and a provisional patent has been filed for this application.

One of the most important sub-projects of the research is the development of a computer-assisted diagnosis system that is able to detect TB in children based on their X-rays.

Says Vaughan: “Currently data sets of X-rays taken by the Statscan system are being gathered at the Red Cross Children’s Hospital. The aim is to automatically outline the airways on an X-Ray, for which the Lodox Statscan is particularly well suited since it can image fine detail on the image. Changes in the airway diameter or structure, which could be indicative of TB or HIV, will be immediately detected, speeding up diagnosis and, of course, treatment.

“In the geographic setting of the Red Cross Children’s Hospital, this is particularly meaningful as most parents of infected children are from less prosperous areas. Early detection and treatment can mean a cure and we all know that TB is one of our biggest health problems.”

Another area under development is that of the ever-unpopular mammogram, which women have come to detest. Lodox, in collaboration with the research team and with additional funding from the National Institutes of Health in the US, is developing a mammography machine that will significantly lower radiation exposure and improve patient comfort through the reduction of painful compression.

This will be achieved by improving the image quality by optimising two key parameters: modulation transfer function and detective quantum efficiency. Overall, reduced time spent in the exam room as a result of these technological improvements means increased patient throughput. The lower radiation level addresses the concerns raised by medical members about repeated mammograms in older women.

Stereo X-ray image visualisation is being developed to improve the presentation of the images to the observer. This is especially useful for studies where three-dimensional positioning is required, as in radiation therapy, and is widely used in preparation for orthopaedic operations.

Digital image processing is the diagnostic tool of today and tomorrow. Conventional X-rays can give both false negative and false positive pictures, but this new technology will close these gaps and continue to bring clearer, more precise images to the physician at lower radiation dosages than thought possible to date.

Better diagnostics lead to quicker, more effective treatment and increased cure rates, as will be the case with detecting TB automatically. This technology could change the face of the TB epidemic in centres where it is used.