The scientists believe the discovery could lead to treatment which targets only cancer cells and kills them with nuclear fission instead of chemicals that poison the body.

In a report published in the Proceedings of the National Academy of Sciences, they say a family of chemicals has been discovered which can deliver boron directly into a tumour to destroy it.

The boron exposes the cancer cells to a beam of neutrons, which through the release of large amounts of energy or nuclear fission, kills the cells by destroying their DNA.

The treatment would only affect the tumour without attacking other healthy cells nearby, making the therapy more comfortable for patients.

'Land-mine'

Professor Frederick Hawthorne of UCLA's Molecular Sciences Department, said preliminary tests were encouraging and the procedure was simple in that it took only a single session of therapy.

The idea of using boron-based compounds to fight cancer has been considered for more than 60 years, but Professor Hawthorne said the new family of chemicals was more effective at getting the boron into the nucleus of the cancer cells.

Once there, the boron is "activated" by exposing the cancer cells to a beam of neutrons, producing nuclear fission that destroys the cells' DNA.

"Boron can be considered something like a land mine, because it's just sitting there until something comes along and steps on it," Professor Hawthorne said.

"In this case, that something is the neutron. And when it goes off, it destroys whatever happens to be around it," but without destroying healthy cells nearby.