A new breast scan using a souped-up kind of x-ray called a CT scan may be more accurate than a standard mammogram - and much less uncomfortable, US researchers say.
The new scan produces three-dimensional pictures, which are better at showing whether a spot on an x-ray is a benign lesion or a tumour, the researchers at the University of Rochester in New York said.
It can also provide pictures of tissue around the ribs and outer breast toward the armpit, where 50 per cent of cancers are found, the researchers told a Radiological Society of North America meeting in Chicago.
The Cone Beam Breast Computed Tomography scanner takes 360-degree views of breast anatomy, with no need to compress the breast between cold glass plates.
"We have one case in which a cancer shows up phenomenally well using this new imaging system, whereas when you look at the same lesion on a mammogram it is hard to detect," said Dr Avice O'Connell, director of women's imaging at the university's medical centre, who led the study.
O'Connell's team is still doing trials of the system and will not have a full study until 60 women have undergone the imaging.
But the results so far suggest the CT scan can detect more of a tumour than a mammogram can, O'Connell said. So far the Cone Beam scanner has detected every tumour seen on a mammogram, she said.
"The mammogram is not 100 per cent. It never was," O'Connell said.
"Mammograms in the best hands in the world will miss 15 per cent of tumours."