A study of about 50,000 American women found that digital mammograms are 15-28% better at spotting breast cancer in women under the age of 50 than standard film technology. Most under fifties have not yet experienced the menopause, their breasts are denser. The researchers said the two technologies were pretty similar when detecting cancers in older women.

Dr Etta Pisano of the University of North Carolina, Chapel Hill, who led the study said that as younger women have denser breasts, their scans are harder to interpret in great detail. When tumours do appear in younger women they tend to be the more aggressive ones and have a higher mortality rate.

The difference between digital and film mammogramsis that the digital x-ray displays the image on a computer. The health professional can then tweak the image (contrast) in order to study unusual areas. With a film mammogram, he/she needs to get out a magnifying glass - the image cannot be manipulated.