‘A whole new adventure’: radiography and archaeology meet at the University of Cumbria

Uncovering Roman Carlisle

Over the past nine years, hundreds of volunteers on community archaeology project Uncovering Roman Carlisle (URC) have exposed the remains of a high-ranking imperial palace complex. The site includes a massive Roman bathhouse, a temple and a religious pillar known as a Jupiter Column with direct connections to the Severan Dynasty (193-235 AD).

Alongside the architecture, the dig has yielded hundreds of artefacts. But after centuries underground, iron and copper alloys develop a dense, hardened layer of compacted corrosion and minerals called a ‘concretion’. This thick outer shell makes it impossible to identify the object inside with the naked eye alone.

Historically, the URC project relied on a private provider to X-ray these items, but the images were often of basic quality. Realising the need for higher-tier imaging, URC charity volunteer Kathryn Nichol reached out to Dr MacDonald.

Adapting technical skills for antiquity

Earlier this year, across two sessions taking place on 18 March and 12 June, a cohort of 14 diagnostic radiography students was introduced to the project. After a briefing on the site’s historical significance, they headed to the university’s X-ray facilities to carry out their investigations. 

Working alongside Dr MacDonald, senior lecturer Kimberley Bradshaw, senior technician Jonny Forsyth and the students had to rapidly adapt their clinical knowledge to non-human subjects. Without standard protocols, they had to think critically about exposure parameters, compensating for the extreme density of the concretions, the required penetration of the X-ray beam and the optimal orientation of each object.

“Every time they produced an image, there was great excitement as they huddled around the monitor to view the object,” Dr MacDonald recalls. “Then they were able to decide to X-ray it again, or change the orientation. Being able to think on your feet in an unfamiliar situation is really helpful for increasing their flexibility of thought.”

Through careful manipulation of contrast and positioning, the students successfully cut through the corrosion to identify a trove of Roman artefacts, including:

• A utility knife
• Fragments of sword blades
• Spear points and ferrules (the metal base of a spear)
• Lynch pins and heavy-duty nails
• An iron strigil (a curved tool used in Roman bathhouses to scrape oil, sweat and dirt from the skin)

The value of ‘paleoradiography’

To ensure the students extracted the maximum educational value from the day, Dr MacDonald consulted with James Elliott, programme lead for the diagnostic radiography course at Canterbury Christ Church University. Elliott holds a unique dual expertise: a BSc in both archaeology and diagnostic radiography, a master’s in forensic radiography and registration with the Chartered Institute of Archaeologists. His specialism in paleoradiography – scanning unearthed artefacts and remains – made him the ideal adviser.

He stresses that X-raying antiquities is an exceptional way for students to deepen their grasp of fundamental radiation physics. “A core part of learning to become a radiographer is understanding how X-rays interact with matter, and the image quality that will come out as a result,” Elliott explains. “With patients you can ask them to move around – with most of these objects, you really have to think about the settings and the technique you have to apply to get a good image.”

For the archaeological field, this non-destructive testing is vital. By cataloguing what ancient peoples left behind, archaeologists build a much clearer picture of human material culture and activity.