MODEL RELEASED. Mammography. Radiologist positioning a woman for a mammogram, an X-ray image used to screen for breast cancer or investigate breast lumps. The breast (not seen) is being flattened between an upper plastic cover and a metal X-ray plate, allowing its internal tissues to be seen on a low-dose X-ray. Routine screening allows breast tumours to be detected at an early stage. Once a tumour has been located on a mammogram, a biopsy (tissue sample) can be taken to confirm whether it is cancerous. This is Siemens' Mammomat 3000 Nova system.