Breast cancer: mammogram of a female breast showing fine calcification (faint white flecks) in a cancerous tumour. Fine calcification is a typical feature of cancerous tumours, although it is also present in benign fibroadenomas. Mammography is a special X-ray technique that is used to visualize soft tissues of the breast as a means of screening women for breast cancer. The majority of breast cancers originate in the mammary ducts & the remainder in the lobular glands. Most tumours of either type show early evidence of invasive (malignant) behaviour, but both types may exist in non-invasive forms.