Radiography – the use of electromagnetic radiation such as X-rays – is a way of examining objects without damaging or destroying them. Developed for medical diagnosis, radiography is now widely used to look at archaeological objects, including human remains.

X-ray

When X-rays are directed at an object, some are absorbed and some pass through the object to form an image on photographic film placed on the other side. Some substances absorb more radiation than others, and more rays will be absorbed by thick materials than thin, creating lighter and darker areas on the photographic film. In the case of human remains, X-rays can be used to show any damage to the skeleton, giving clues to how the person lived and died.

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CAT scans

While X-rays provide a flat, two dimensional picture, CAT (Computerised Axial Tomography) scanning gives a three dimentional image. X-rays are directed at the object from all sides to create images of slices through it. A computer uses these to generate a three dimensional reconstruction of the inside of the object.

Used in medicine to diagnose cancer and other conditions that affect soft tissue, CAT scanning is a valuable archaeological tool. It was used to examine the remains of the baby ice mummy found in Greenland.

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X-ray shots of a bog body

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