Picture this: a surgeon's hands are still inside a patient's skull when, two hours later, a definitive diagnosis arrives. That is no longer science fiction. Researchers at the University of Nottingham's Brain Tumour Research Centre of Excellence have developed a genomic test that can identify the precise type of brain tumour while the patient is still on the operating table. The NHS has already begun piloting it at five specialist centres across England, including Great Ormond Street Hospital and King's College Hospital in London.

How does it work? A small tissue sample is sent from the operating theatre to a nearby pathology lab, where it is loaded into a sequencing machine about the size of a shoebox, made by Oxford Nanopore. Inside the device, individual molecules of DNA are threaded through a nanopore — a hole so tiny it can only be measured in nanometres — and the sequence of genetic letters is read in real time. The result is a detailed genomic profile of the tumour, something that a conventional microscope simply cannot provide.

Until now, patients have had to wait up to eight weeks for an equivalent diagnosis. That wait is not merely uncomfortable — it can be lethal. Brain tumours are the single biggest cause of cancer death in children and adults under 40 in the UK, so every lost week matters enormously. Professor Frankie Swords, NHS Medical Director, has described the test as "a huge leap forward for patients.

" Consultant neurosurgeon Stuart Smith, who co-led the research, put it even more sharply: surgeons can now make critical decisions with detailed genomic information at the exact moment those decisions must be made.