Illustration of a mammogram A mobile<unk>  unit in New Zealand During the procedure, the breast is compressed using a dedicated<unk>  unit. Parallel-plate compression evens out the thickness of breast tissue to increase image quality by reducing the thickness of tissue that X-rays must penetrate, decreasing the amount of scattered radiation (scatter degrades image quality), reducing the required radiation dose, and holding the breast still (preventing motion blur). In screening<unk> , both head-to-foot (craniocaudal, CC) view and angled side-view (mediolateral oblique, MLO) images of the breast are taken. Diagnostic<unk>  may include these and other views, including geometrically magnified and spot-compressed views of the particular area of concern. Deodorant, talcum powder or lotion may show up on the X-ray as calcium spots, so women are discouraged from applying them on the day of their exam. There are two types of mammogram studies: screening mammograms and diagnostic mammograms. Screening mammograms, consisting of four standard X-ray images, are performed yearly on patients who present with no symptoms. Diagnostic mammograms are reserved for patients with breast symptoms, changes, or abnormal findings seen on their screening mammograms. Diagnostic mammograms are also performed on patients with breast implants, breast reductions, and patients with personal and/or family histories of breast cancer. Until some years ago,<unk>  was typically performed with screen-film cassettes. Today,<unk>  is undergoing transition to digital detectors, known as digital<unk>  or Full Field Digital<unk>  (FFDM). The first FFDM system was approved by the FDA in the U.S. in 2000. This progress is occurring some years later than in general radiology. This is due to several factors: # The higher spatial resolution demands of<unk>  # Significantly increased expense of the equipment # Concern by the FDA that digital<unk>  equipment demonstrate that it is at least as good as screen-film<unk>  at detecting breast cancers without increasing dose or the number of women recalled for further evaluation. As of March 1, 2010, 62% of facilities in the United States and its territories have at least one FFDM unit. (The FDA includes computed radiography units in this figure.) Mammograms are either looked at by one (single reading) or two (double reading) trained professionals: these film readers are generally radiologists, but may also be radiographers, radiotherapists, or breast clinicians (non-radiologist physicians specializing in breast disease). Double reading, which is standard practice in the UK, but less common in the US, significantly improves the sensitivity and specificity of the procedure. Clinical decision support systems may be used with digital<unk>  (or digitized images from analogue<unk> , but studies suggest these approaches do not significantly improve performance or provide only a small improvement. Digital Digital<unk>  is a specialized form of<unk>  that uses digital receptors and computers instead of X-ray film to help examine breast tissue for breast cancer. The electrical signals can be read on computer screens, permitting more manipulation of images to allow radiologists to view the results more clearly . Digital<unk>  may be "spot view", for breast biopsy, or "full field" (FFDM) for screening. Digital<unk>  is also utilized in stereotactic biopsy. Breast biopsy may also be performed using a different modality, such as ultrasound or magnetic resonance imaging (MRI). While radiologists had hoped for more marked improvement, the effectiveness of digital<unk>  was found comparable to traditional X-ray methods in 2004, though there may be reduced radiation with the technique and it may lead to fewer retests. Specifically, it performs no better than film for post-menopausal women, who represent more than three-quarters of women with breast cancer. The U.S. Preventive Services Task Force concluded that there was insufficient evidence to recommend for or against digital<unk> . Digital<unk>  is a NASA spin-off, utilizing technology developed for the Hubble Space Telescope. As of 2007, about 8% of American screening centers used digital<unk> . Around the globe, systems by Fujifilm Corporation are the most widely used. In the United States, GE's digital imaging units typically cost US$300,000 to $500,000, far more than film-based imaging systems. Costs may decline as GE begins to compete with the less expensive Fuji systems. 3D<unk>  Three-dimensional<unk> , also known as digital breast tomosynthesis (DBT), tomosynthesis, and 3D breast imaging, is a mammogram technology that creates a 3D image of the breast using X-rays. When used in addition to usual<unk> , it results in more positive tests. Cost effectiveness is unclear as of 2016. Another concern is that it more than doubles the radiation exposure. Photon counting Photon-counting<unk>  was introduced commercially in 2003 and was shown to reduce the X-ray dose to the patient by approximately 40% compared to conventional methods while maintaining image quality at an equal or higher level. The technology was subsequently developed to enable spectral imaging with the possibility to further improve image quality, to distinguish between different tissue types, and to measure breast density. Galactography A galactography (or breast ductography) is a type of<unk>  used to visualize the milk ducts. Prior to the<unk>  itself, a radiopaque substance is injected into the duct system. This test is indicated when nipple discharge exists.
Mammography
Xeromammography
Breast MRI
Scintimammography
Breast imaging
Breast biopsy
Breast ultrasound
Breast self-examination