Andrew Masterson
Andrew Masterson is a former editor of Cosmos.
A novel approach to non-destructive investigation has produced an image of a 2500-year-old Egyptian mummy’s hand, revealing detail fine enough to distinguish individual cells.
The image, reported in the journal Radiology, resulted from a modified type of computed tomography (CT) pioneered by a team led by Jenny Romell from the Albanova University Centre in Stockholm, Sweden.
Standard CT produces images by means of absorption contrast – that is, it takes advantage of the fact that different materials absorb different amounts of x-rays.{%recommended 7767%}
The approach works very well for examining hard materials, such as bone, but produces only low resolution results when applied to soft tissue.
Romell and her colleagues instead used a method called “propagation-based phase-contrast”. In this, the CT scanner constructs an image based not only on absorption, but also on the phase shift that occurs when the x-rays pass through the sample. Combining both sets of data provides a much higher contrast results for flesh.
The mummy’s hand – which usually resides in Sweden’s Museum of Mediterranean and Near Eastern Antiquities – has been dated to around 400 BCE.
Romell’s team achieved an image with a resolution of between six and nine micrometres – or just larger than a human red blood cell. They were able to identify fat cells, blood vessels and nerves in extraordinary detail.
Currently, the only other available method for accessing such small structures in ancient corpses is through physically removing tissue samples – a method that by definition degrades the specimen itself.
“Just as conventional CT has become a standard procedure in the investigation of mummies and other ancient remains, we see phase-contrast CT as a natural complement to the existing methods,” Romell explains.
“We hope that phase-contrast CT will find its way to the medical researchers and archaeologists who have long struggled to retrieve information from soft tissues, and that a widespread use of the phase-contrast method will lead to new discoveries in the field of paleopathology.”
