A safer alternative to the risks of X-rays

Using ultrasound imaging to diagnose scoliosis - curvature of the spine - is a radiation-free alternative to traditional X-rays.

A Polytechnic University team has perfected the technique, arguing that it is safer, quicker and cheaper than conventional assessment methods. Zheng Yongping, professor of the university's interdisciplinary division of biomedical engineering, says: 'One of the best things about using ultrasound is its safety. It can be done frequently to closely monitor a condition.

'Because X-ray [radiation] accumulates in our body every time we do it, some countries have even banned X-rays to avoid cancer, no matter how unlikely it is. This makes it difficult to monitor the curing effect during treatment.'

The Hong Kong project won a gold medal at the 40th International Exhibition of Inventions of Geneva last month. Zheng says their device may soon be sold as a commercial product.

Up to 4 per cent of the population in Hong Kong is affected by spinal scoliosis, government figures show. It involves an abnormal S-shaped or C-shaped sideways curvature, and is the most common form of spinal deformity found among children. It can be stopped or reversed in some cases, but takes years of repeated visits to doctors, treatment or therapies, and frequent X-ray examinations.

The PolyU division has also used the ultrasound technique to diagnose breast cancer, liver fibrosis (a scarring response to injury) and diabetic foot.

Its test for scoliosis can yield an assessment almost instantly. Conventional X-rays, with their radiation, cannot be done too often and the waiting time for a result ranges from minutes to hours. But X-rays are mainly used to measure a spine curvature and help in the course of treatment. X-rays cannot be used in Hong Kong more than once in nine months for the assessment of scoliosis, Zheng says. In Singapore, X-rays are not used for such assessments.

He says other alternatives include computer tomography - also know as a CAT scan - 'which has more radiation', and magnetic resonance imaging (which visualises internal structures of the body), 'which is OK but has to be done lying down, which distorts the spine's position'.