New imaging technology has been developed to help picture how tumours form.

Early diagnosis and treatment of patients with cancer could be helped by the tool which researchers at Edinburgh University use to detect the onset of metastatic cancers - when tumours spread and take hold in new areas of the body.

The scientists have developed a chemical signal that lights up to show previously unseen immune cells called metastasis-associated macrophages, which help cancer cells form metastatic tumours.

It has long been known that before cancer spreads from one area to another - often fairly distant from the original cancer source - it sends messenger cells to 'prepare the ground'.

The team at Edinburgh University hope that their technique can be developed to help spot tiny changes inside the body’s tissues early.

They think doctors could use also the technology in the future to monitor how patients are responding to treatment, by directly tracking metastasis-associated macrophages.

Dr Marc Vendrell, of the university's Centre for Inflammation Research, said: “This is an important advance in our abilities to study the role that immune cells play in tumours. We hope that this new technology will accelerate the design of better therapies to halt the development of metastasis.”

Dr Takanori Kitamura, of the MRC Centre for Reproductive Health, added: "This advance will be important in improving patient diagnoses.”

The study is published in the journal Angewandte Chemie.