Research into how the human body repairs damaged DNA has been described as a "major breakthrough".
One of the images used by the research team
The way that cells protect themselves from diseases like cancer has been the focus of a study by scientists at Dundee and Leeds Universities.
They used special x-rays to build 3D pictures of a particular enzyme, which recognises and fixes damaged DNA.
The researchers used the images to get a better understanding of how the process works.
The team studied an enzyme, known as T7 endonuclease 1, which played a central role in identifying damaged or "branched" DNA.
The scientists said it was only DNA repair that stopped people from contracting cancer on a regular basis.
They said the research represented a major breakthrough in investigating how DNA was formed and replicated by viruses.
Professor David Lilley from Dundee University said: "This is a big step forward, and provides great new insight into the recognition of branched DNA.
"The new structural knowledge will provide considerable impetus to take this field further."