The technique, known as 'photodynamic diagnosis', is already used to diagnose and treat other types of cancers, for example, certain skin cancers.

BBC: Shining a light on bowel cancer

Preimplantation genetic diagnosis (PGD), the technique used to see if an embryo is a match, is legally permitted now if a genetic condition is present in a family.

BBC: Embryology Bill: The key points

Breast cancer diagnosis at Derriford Hospital will be carried out using a new technique and upgraded technology, say the hospital's doctors.

BBC: Derriford Hospital uses 3D imaging for cancer diagnosis