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Ordinary Light Tests

Lateral curvature of the spine can now be detected without the use of X-rays. Tom Huysmans of K.U.Leuven's Department of Biomechanics and Graphic Design has developed a technique using ordinary light which approaches the precision of radiology. The technique is important for research into scoliosis, a spinal column deformity affecting 2% of adolescents.

Dr Huysmans projects light onto a patient's exposed back while a camera takes a photo. A computer then processes the resulting image and generates a three-dimensional line drawing. By examining the drawing's variations in contrast, Huysmans can determine the position of the spinal column to an accuracy of a few millimetres. The actual position is compared with an ideal curve for the spinal column so that the degree of lateral deformity can be measured. The entire procedure is based solely on surface information, thus greatly reducing the need for X-rays.

Dr Huysmans has made more than 500 comparisons of his images with X-ray images, with consistent results in each case. This shows the method is reliable, and it can be used in 95% of cases. Only patients with an unusually thick layer of fatty tissue on their back are excluded due to insufficient image contrast.

This technique is especially important for children, since scoliosis patients currently receive regular X-rays from a young age and children are much more sensitive than adults to radiation. By using this new method, the children no longer have to be exposed to X-rays.

A further application involves research into good posture in bed. With these images, one can examine the position of the spinal column in someone lying on their sides and thus determine whether the mattress gives enough support at the right places. This contributes to a reduced incidence of lower-back problems.