Dr Hiroki Ueda, one of the researchers, said: "The images reveal cancerous colonies in enough detail to calculate their shapes, volumes, and distributions - characteristics critical to distinguishing between patterns of metastasis.

Further experiments showed how cancer can get better at spreading. Dr Kohei Miyazono said: "Most of the cancer cells appear to die during circulation in the bloodstream and fail to metastasise." But cancers then start producing chemical signals to help them grow. The researchers tested the effect of one of them, called TGF-beta, and showed it dramatically improved the chances of cancers colonising the lung tissue. "[They] are far more likely to survive the journey and form malignant outposts," Dr Miyazono added. It is thought the technology could be adapted to other disciplines, including how the body's cells behave in people with autoimmune diseases.