Thousands of women could have their breast cancer detected more quickly if computers are used to double-check mammograms, research indicates today.

Scientists funded by Cancer Research UK have found that using a computer instead of a doctor to read breast x-rays could almost halve the workload of radiologists at a time when there is a severe shortage of doctors pursuing this speciality.

The computer-aided detection (CAD) programme is also more accurate, picking up 6.5% more cancers than two experts checking x-rays, says the study.

Under the national screening programme two radiologists check each x-ray of women aged between 50 and 70. But a shortage of radiologists means that thousands of women miss out on being screened within the specified three years.

The CAD system could prevent this, according to Stephen Duffy, professor of cancer screening at Queen Mary, London, and Cancer Research UK, who worked on the research, published today in the journal Radiology. "In some areas women do not get their screening invitations as regularly as they should - every three years - because there are simply not enough experts to go round.

"There are thousands of women and potentially tens of thousands of women who have slipped beyond the [deadline] and this could go a long way to remedying this."

For the study, researchers took 10,000 mammograms, taken in 1996, which had previously been read by two radiologists. The computer then "read" each one and flagged up any suspicious features or irregularities that could be caused by tumours for one radiologist to check. The radiologist also looked at each one.

The results showed that the cancer detection rate was even better than the traditional method, with the computer picking up 6.5% more patients who it later transpired had cancer but who had been missed by the two radiologists.

The team are now conducting a second trial of 30,000 women to confirm the result is as accurate in day to day diagnosis. Each woman will have a routine double reading before taking part.

Professor Fiona Gilbert, of Aberdeen University, who led the study, said: "The results of this trial are very encouraging. The mammograms studied were from a sample taken in 1996, so that all cancers that developed subsequently in this group of women could be included. The study was retrospective so the radiologists taking part in the trial knew no action would be taken as a result of their decisions."

Professor John Toy, medical director for Cancer Research UK, said: "If a prospective trial confirms these results, it would be very good news for the national screening programme and more importantly, therefore, also for women."

The national programme screened 1.48 million women in England last year, 12,000 of whom had cancer.

A spokeswoman for the NHS breast screening programme said that 70% of women aged between 50 and 70 were seen within the three-year target and admitted that it needed 43 more radiologists in England alone. Latest figures show there are 3,008 radiologists, although a 2002 report by the Royal College of Radiologists predicted that the number needed would reach 3,300 over five years.