It delivers twice as much radiation as a conventional mammogram, but some radiologists say it gives a clearer image.

WSJ: Dense Breasts Pose a Dilemma in the Search for Breast Cancer

They spread rapidly and are resistant to radiation and to conventional drugs, leaving patients with little hope of survival.

ECONOMIST: Cancer treatment

Conventional CT scans are used to work out the shape of the place where a dose of radiation needs to be concentrated in order to attack a tumour without damaging nearby healthy tissue.

ECONOMIST: Modern X-ray technology