Health hazards that X-rays miss

FIVE-YEAR-OLD Billy lay in bed in his Hong Kong flat, eyes closed in peaceful sleep. But his mother, watching over him, was troubled. For two months her son had had a persistent cough. Medical specialists suspected asthma. But nothing the doctors suggested had relieved the boy of his coughing and wheezing.

Billy's mother felt she should not worry too much. Her son was a lively boy and chest X-rays had shown his lungs and respiratory tract were clear.

But paediatrician Dr Tseng (who prefers to remain anonymous) took a different line of questioning: had Billy swallowed anything unusual lately? And gradually the problem afflicting the child emerged, leading to a report in the latest issue of the New England Journal of Medicine and new questions on toy safety.

Four months earlier, his father recalled, Billy had swallowed a Lego piece the size of a peanut. He did not choke or have difficulty breathing at the time so the parents thought the part had simply passed through his system.

Dr Tseng thought otherwise: 'I suspected the child's condition might have something to do with the piece of Lego. I stuck pieces of Lego similar to the one he might have swallowed on his shoulder with celluloid tape and stood him against an X-ray machine.

'The X-ray shows no Lego pieces. It was then that we discovered Lego, like many other toys, does not show up on an X-ray. They are what we technically call radiolucent.

'All along, we thought the child had asthma, when in fact, he had had a piece of Lego lodged in his airway for four months.' Billy's condition has led doctors involved in the case to ask why manufacturers do not make toys that are detectable by X-ray.