By the way... only have an x-ray if you absolutely need one

AS CHILDREN, my siblings and I were marched to the Finchley Boot and Shoe Company in London to purchase stout and sensible footwear, and I have a lasting memory of the sinister but fascinating machine there on which customers could see the image of the bones of their feet, to check the fit of their shoes.

This was an X-ray fluoroscope, and by standing on a platform an eerie greenish image was displayed on the screen. But, to our dismay, it was forbidden to go near this magical device — strict parental control was in place. There were no health-and-safety rules in this post-war era — yet somehow our father knew with absolute conviction of the dangers of X-rays.

I was reminded of my early shoe-shopping experience this week, after reading about research suggesting that having a dental X-ray may increase the risk of a brain tumour. Experts have pointed out that the results relied on brain tumour patients recalling the number of X-rays they have had — and, by nature, cancer patients are more likely to remember something that they think may have given them cancer, compared with healthy subjects.

Despite this, and the fact that the level of radiation we receive from X-rays is small, patients must still be informed about the radiation they receive from scans.

Radiation from medical imaging accounts for about a sixth of our exposure to ionizing radiation — the type that can cause cancer — with the remainder being in the natural environment, for instance originating from the gas radon, which leaks from granite.

The actual risk of cancer associated with lowdose medical imaging remains controversial, as there are no studies to confirm cancer arising directly from these procedures. Yet there is agreement in the medical and scientific world that the risk from scans that use radiation, such as X-rays or CT (but not MRI), is real. Therefore, every time a doctor or dentist plans an X-ray procedure, a risk benefit analysis is being made — and it is important that we, as patients, are aware of this. In particular, this means that ordering scans of this type for ‘health screening’ — check-ups on the worried-well — is not without potential hazard. So a CT scan of the lungs in a lifetime heavy smoker, to see if there is an early and still treatable cancer, might just about be valid; but such an exposure to radiation in someone who has never smoked is clearly not.

Careful consideration is what is needed when ordering exposure to X-rays, we must never forget it, and that’s why we no longer X-ray children’s feet to see if their shoes fit.