Breast imaging

The best mammographic images are produced when the breast is compressed.

Mammography is the process of using low-energy X-rays (usually around 30 kVp) to examine the human breast, which is used as a diagnostic and screening tool. The goal of mammography is the early detection of breast cancer, typically through detection of characteristic masses and/or microcalcifications. For the average woman, the U.S. Preventive Services Task Force recommended (2009) mammography every two years in women between the ages of 50 and 74.[1] The American College of Radiology and American Cancer Society recommend yearly screening mammography starting at age 40.[2] The Canadian Task Force on Preventive Health Care (2012) and the European Cancer Observatory (2011) recommends mammography every 2–3 years between 50 and 69.[3][4] These task force reports point out that in addition to unnecessary surgery and anxiety, the risks of more frequent mammograms include a small but significant increase in breast cancer induced by radiation.[5][6] Additionally, mammograms should not be done with any increased frequency in people undergoing breast surgery, including breast enlargement, mastopexy, and breast reducation.[7] The Cochrane Collaboration (2013) concluded that the trials with adequate randomisation did not find an effect of mammography screening on total cancer mortality, including breast cancer, after 10 years. The authors of systematic review write: "If we assume that screening reduces breast cancer mortality by 15% and that overdiagnosis and overtreatment is at 30%, it means that for every 2000 women invited for screening throughout 10 years, one will avoid dying of breast cancer and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress including anxiety and uncertainty for years because of false positive findings." The authors conclude that the time has come to re-assess whether universal mammography screening should be recommended for any age group.[8] They thus state that universal screening may not be reasonable. The Nordic Cochrane Collection, which in 2012 reviews updated research to state that advances in diagnosis and treatment make mammography screening less effective today. They state screening is “no longer effective.” They conclude that “it therefore no longer seems reasonable to attend” for breast cancer screening at any age, and warn of misleading information on the internet.

Mammography has a false-negative (missed cancer) rate of between 7 and 12 percent.[9] This is partly due to dense tissues obscuring the cancer and the fact that the appearance of cancer on mammograms has a large overlap with the appearance of normal tissues. A meta-analysis review of programs in countries with organized screening found 52% over-diagnosis.Digital breast tomosynthesis

Digital breast tomosynthesis (DBT) can provide a higher diagnostic accuracy compared to conventional mammography. In DBT, like conventional mammography, compression is used to improve image quality and decreases radiation dose. The laminographic imaging technique dates back to the 1930s and belongs to the category of geometric or linear tomography.[10]

Because the data acquired are very high resolution (85 – 160 micron typical ), much higher than CT, DBT is unable to offer the narrow slice widths that CT offers (typically 1-1.5 mm). However, the higher resolution detectors permit very high in-plane resolution, even if the Z-axis resolution is less. The primary interest in DBT is in breast imaging, as an extension to mammography, where it offers better detection rates with little extra increase in radiation.[11][12]

Tomosynthesis is now Food and Drug Administration (FDA) approved for use in breast cancer screening.[13]

Xeromammography is a photoelectric method of recording an x-ray image on a coated metal plate, using low-energy photon beams, long exposure time, and dry chemical developers. It is a form of xeroradiography.[14]

Galactography is a medical diagnostic procedure for viewing the milk ducts. The standard treatment of galactographically suspicious breast lesions is to perform a surgical intervention on the concerned duct or ducts: if the discharge clearly stems from a single duct, then the excision of the duct (microdochectomy) is indicated;[15] if the discharge comes from several ducts or if no specific duct could be determined, then a subareolar resection of the ducts (Hadfield's procedure) is performed instead.[15] To avoid infection, galactography should not be performed when the nipple discharge contains pus.[16]