A former colleague – in the hospital where I worked – called the scans to which patients are now routinely subjected ‘the answering machines’.
This was not meant as a compliment to the technology. It was a lament about the loss in younger doctors of the skills of physical examination of their patients and of logical deduction therefrom. It had taken him a lot of time and trouble to acquire these skills, and now they were almost redundant.
Under the new dispensation, a patient arrived in the hospital, was scanned and received a diagnosis, rather as someone who puts money in a vending machine receives a bar of chocolate. No need for thought or reflection.
Bitterness about changes in the way working methods have changed is not confined to the medical profession.
The poet Vernon Scannell wrote a fine poem about the sorrow of an accounts clerk at the passing of the old leatherbound books of his youth, which he regarded as beautiful.
I remember, however, the excitement caused by the arrival of the CAT scan in medical practice. It was the answer to our prayers, a step on the way to personal immortality via rapid diagnosis.
At first, machines were few and far between. Patients who were scanned were a fortunate, important elite, and accordingly felt honoured by their selection.
In the years since, CT scanning (as it is now called) has become routine, rather like blood tests. Everyone with a tinge of headache wants a scan and is not satisfied until he or she has had one.
Every year in the United States, CT scans are performed on very nearly a fifth of the population in a year, on average one and a half times: that is to say, 93 million scans on 62 million people.
So far, I have managed to avoid having such a scan, but I doubt that I shall get through life unscathed. Call no man happy (or healthy) until he has had a scan.
Be that as it may, most people imagine that so great an advance in technology (the inventor was awarded a Nobel Prize) can do only good.
Alas, this is not so, at least if a recent estimation of cancers caused by the radiation involved absorbed during a scan is to be believed. Such estimations are always hazardous, of course. They require sophisticated statistical methods and often entail doubtful assumptions.
We often forget that statisticians are like economists: where there are two of them, there are at least three opinions.
I was once asked to investigate a statistically unusual series of occurrences, only for a subsequent statistician to say that the series was not unusual at all. On the contrary, it was rather to be expected.
At any rate, it was estimated that the 93 million scans performed on 62 million patients in the US would result in 103,000 extra cases of cancer over the lifetimes of the scanned patients. Commonest among these would be lung cancer, followed by bowel cancer.
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Most readers of this magazine, though, need not fear having a CT scan.
They are already too old for a CT-scan-induced cancer, which takes years to develop. There are, perhaps, not many compensations for growing old, but immunity to cancer resulting from CT scans is one of them.
My advice remains not to need scanning in the first place.
