A technology that can spot and blast away tumour cells beneath the skin, has been created by scientists.

The treatment could allow doctors to quickly scan patients' blood without ever removing it from them, to spot circulating tumour cells or CTCs, which can go on to spread around the body and become the deadly metastases that often kill people with cancer, The Independent reports.

It is also able to blast away those CTCs, vastly reducing the number that are circulating in the blood, as well as finding blood clots as they circulate.

These clots are the second leading cause of death in cancer patients and are difficult to find otherwise.

Researchers have long attempted to look at CTCs as a way of understanding the risk of metastasis in patients.

Once discovered, doctors can tell how likely the cancer is to spread and to help direct laser therapies that kill off those cells.

However, that work has been hampered by the fact that they can only take a very small amount of blood, which might not contain any of those CTCs at all.

To address that problem, scientists created the system they refer to as the Cytophone.

This can use pulses of lasers to look beneath the skin of patients with melanoma and look out for the pigmented CTCs as they run through their veins.

By doing so, they were able to spot those problematic CTCs successfully in 27 of 28 patients they tested on, often doing so in as little as 10 seconds. The system is more than 1,000 times more sensitive than existing methods.

Scanning brought back a result within 10 seconds to 60 minutes and did not find a single false positive, the researchers said in a study published in Science Translational Medicine.