Cancer threat from old x-ray equipment

Modern x-ray equipment is safer

Elderly x-ray machines have been linked with a higher rate of breast cancer among the staff who operated them.

It is known that women exposed to high levels of radiation are more prone to developing breast cancer - but the effects of long-term, low-level exposure are not fully understood.

Now, the latest report, in the Journal of the National Cancer Institute, seems to suggest that there is a risk.

There is no evidence that single or even a sequence of x-rays poses any risk to the individual patients undergoing them.

However, there have been worries that staff, although shielded from all but a tiny fraction of each individual x-ray, are exposed to a culmulatively much higher level by carrying out hundreds of procedures each week.

Researchers from the US Food and Drug Administration looked at death rates among 70,000 women radiation technologists who began working between 1926 and 1982.

More than double

Those who started work before 1940 and 1949 were 2.5 times more likely to die from breast cancer than those who started after 1960.

This is significant because prior to 1950, an x-ray technique called fluoroscopy and multifilm was used.

This involved a higher level of exposure than more modern techniques.

The findings were adjusted to take other possible factors into account, such as the age of the women at menopause and their family history of breast cancer.

The risk of breast cancer death increased with the number of years working with the older technique, but not the number of years working with more modern equipment.

Recommended level

In the US, recommended exposures to radiation fell by a third between 1949 and 1958.

The researchers wrote in their report: "Our finding - that breast cancer mortality was highest among technologists who first worked in the earlier calendar periods - probably reflects changing exposures over time."

The UK government is currently investing millions to replace ageing radiotherapy and x-ray scanning machines.