One might have thought that plain common sense would have suggested to the pioneers of X-rays that something invisible which could pass right through you and leave pictures of your bones on photographic plates might not be frightfully good for you. Fortunately for the development of science, the arts, indeed almost all really interesting things, the one thing pioneers seem to have in common is a shortage of that boring overrated thing common sense. They carried recklessly on — I have seen a photograph taken in later life of one of the Curies’ hands; it’s like a still from the ’fifties film ‘The Fly’ — and, not content with making short-exposure photographs they came up with the fluoroscope — great fun but (and) horribly dangerous.
In the fluoroscope the photographic plate is replaced by a glass screen coated with something that glows — usually green — when X-rays hit it. The subject stands between the screen and the X-ray tube, which by now was specially made for the job, using very high voltages to make the electrons move faster, and an anode cunningly designed to encourage them to miss it, whizzing past to hit the glass and be transmogrified. Soon there were fluoroscopes in all the fancy clinics, and patients would stand in front of the screen, perhaps moving about a little or breathing in and out, for ages while doctors peered, humming and hahing and rubbing their chins.
When I was a child the classier shoe-shops had things called ‘Pedoscopes’. Children were dragged kicking and screaming (I do wish parents would take more notice of what their children tell them) to poke their feet, clad in new shoes, into a hole near the bottom of the thing, and they, parents, and shoe-seller could peer in through the top as the child wiggled its toes and the adults nodded approvingly to see the growing-space. I found them fascinating and unlike other children had to be dragged kicking and screaming away from them. No wonder I have flat feet and hammer toes: these things, like the fluoroscopes used for chest examinations, were giving people vast doses of X-rays. Pedoscopes suddenly and quietly disappeared, almost overnight.
In the pioneer days imagination and courage to the point of foolhardiness were virtues. Now that the great virtue is caution to the point of pusillanimity — Raymond Chandler’s Philip Marlow talked proleptically of people being made to live in bungalows in case they fell downstairs — X-rays are done photographically again, even digitally, and exposures measured in milliseconds. No doubt there are now fewer cases of people being damaged by over-exposure to X-rays. But something less quantifiable has been lost.