First X-Ray
On December 22nd 1895 a German physics professor, Wilhelm Röntgen, took the world's first "medical" X-ray. The picture, which is reproduced here, was of his wife's hand and shows a dark shadow on the third finger caused by her ring. Röntgen thoroughly studied this form of radiation, calling it 'X-ray' - the 'X' because the type of radiation was unknown.

X-rays are now used routinely for diagnostic purposes mostly and there are concerns that too many X-rays are taken each year. One study, by the Royal College of Radiologists, investigated the common use of X-rays in patients with head injuries when it was shown that only one patient in 4,800 might benefit. Links between the overuse of X-rays and fatal cancer are constantly under scrutiny.