To SCAN or not to SCAN!

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Comment: The "in-thing" these days is to be able to get a complete SCAN. Those same people would never willingly submit to 1000 X-rays at one time. With all the medical hype, few seem inclined to ask, "What are the inherent dangers and/or consequences of this technology?" Are we once again eagerly following hype-medicine,and swarming around the hi-tech medical Pied Piper? g.s.

Private health scan patients 'at risk of radiation overdose'
By Jeremy Laurance,
Health Editor 01 October 2003 The Independent UK

Private-sector clinics that offer patients hi-tech screening to check for signs of heart disease or cancer may be exposing them to cancer-causing doses of radiation, experts warned yesterday.

Demand for the scans, which can provide clear images of internal organs, is growing rapidly among the health conscious. At least three companies have opened clinics offering "whole body" CT (computed tomography) scans in the Harley Street area of London in the past year.

The patient lies on a table and the circular scanner passes around them, taking a series of X-ray pictures through the body. The National Radiological Protection Board said a single CT scan involved a dose of radiation up to 1,000 times that of a chest X- ray. X-rays are known to cause cancer and the board said that the dose level used would cause cancer in one in a thousand patients.

Barrie Wall, head of medical dosimetry at the board, said: "I am not concerned if these scans are justified. But what is a little worrying is that CT scanning is expanding so rapidly. The images are so fantastic that not a lot of attention is being paid to the doses used." The use of CT scans by private-sector clinics as a preventive screening test to detect early signs of disease rather than to diagnose existing symptoms was hard to defend, Mr Wall said. "I really don't think that is justified. The doses [of radiation] will be quite significant and they [the clinics] never mention that."

The amount of radiation delivered in a CT scan had to be weighed against the likely benefits. "It is 1,000 times higher than a chest X-ray and a lot of CT scans involve that sort of exposure.

"For a person in their 30s or 40s, that means a one in 1,000 risk of cancer. These are not insignificant risks," Mr Wall said.

Patients must be referred by a GP or consultant before they can have a scan, but some commercial clinics offer a consultation with one of their doctors who can authorise the test. At Vital Imaging, where the website boasts "as seen on Richard and Judy" (the TV chat show), a receptionist said its scanning equipment operated at higher speed and with a lower radiation dose than conventional machines. "It is five times more expensive. That is why it is not available on the NHS," she added.

The Lifesyne centre, which opened in Westminster last week, also claims to offer high- speed, low-dose CT scans. A radiographer at the centre said: "If you were having one every day I would be concerned, but if you are having one every couple of years it should not be a problem."

Medical X-rays account for 15 per cent of the total radiation to which the population is exposed. Most of the rest is natural background radiation such as radon from granite rocks.

Advancing technology has halved the dose of radiation used in X-ray examinations over the past decade. But the use of sophisticated screening tests, including CT scans and angiography (X-ray examination of the heart), has grown so fast that the total dose of radiation from medical sources to the population is increasing.

The board is surveying the use of CT scans and the doses of radiation used and is due to publish its findings shortly. In its latest review of NHS hospitals, the board found a 20-fold difference in the level of radiation delivered in the same X-ray examinations in different hospitals. Mr Wall said the reasons could be old equipment or because the consultant in charge had a different way of doing things from his colleagues.

"Twenty years ago, we thought 20 to 30-fold differences between hospitals were alarmingly high. We set reference levels and hoped these would reduce the variation.

"What has happened is that all hospitals have shifted downward to using lower doses of radiation, but the variation has remained the same. It is a bit surprising."

1 October 2003 09:27 M Eaglemeare

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