A mammogram is a low dose x-ray of the breast used to detect and diagnose breast disease, or to provide a baseline reference for later comparison. Multiple images are obtained by different positioning of the breast. The breast compression during mammography is an essential component to produce an optimal diagnostic mammogram. Film mammography units use film to both capture and display the image; digital mammography units use electronic equipment.
A spot compression reduces the thickness of the area of interest and improves contrast and separation of breast tissues.

Mammography is a diagnostic imaging procedure of the breast to detect and evaluate breast disease. Mammography is widely used as a screening method and plays a key role in early breast cancer detection.
The screening mammography is used to detect breast changes in women who have no signs or symptoms or noticed breast abnormalities. The goal is to detect a breast tumor before any clinical signs are observable.
A diagnostic mammography is used to investigate suspicious breast changes, such as a breast lump, an unusual skin appearance, breast pain, nipple thickening or nipple discharge.
A breast screening or standard mammography requires two mammograms from different angles of each breast including craniocaudal view and mediolateral view. Additional images can be made from other angles or focus on microcalcifications or other suspicious areas.
A mammogram is created by special mammography equipment with long wavelength of the used x-rays. Film-screen mammography is still the most widely used technology, but the state of the art technique is digital mammography. Conventional x-ray equipment was used to produce mammograms until dedicated mammography equipment became available in the late 1960s. Film-screen mammography and xeromammography, introduced in the early 1970s, used lower radiation doses and produced sharper mammograms. The second generation of mammography systems has been introduced in the early 1980s. Chief disadvantages of analog mammography include the labor-intensive handling of the cassettes, relatively slow processing time, the lack of a direct interface to the x-ray system, and no post processing possibilities.
Mammograms of high quality should be done with the lowest radiation dose as possible. Adequate breast compression is important due to shortening of the exposure times, immobilization of the breast, reduction of motion and blurring and prevention of overpenetration by means of equalizing breast thickness.
Further breast imaging procedures include breast ultrasound and breast MRI.

The digital mammography is an electronic imaging procedure of the breast. The number of breast imaging facilities equipped with digital mammography (also called computed radiography mammogram (CRM), CR mammogram) is growing due to a number of advantages.
Digital images can be stored directly in a picture archiving and communication system (PACS) and allows the printing, enhancement, magnification, or brightness and contrast manipulation for further evaluation. The sensitivity of digital mammography compared to film mammography is better in women with dense breasts, a population at higher risk for breast cancer, due to these post processing possibilities.
'The American College of Radiology's (ACR) Imaging Network found that digital mammography detected up to 28 percent more cancers than film-screen mammography in women age 50 and younger, premenopausal and perimenopausal women, and women with dense breasts, as reported in October 2005 in the New England Journal of Medicine.'

Advantages of digital mammography:
Existing mammography equipment can be converted to 'digital' operation, which allows cost savings compared to integrated digital mammography systems.

See also Breast MRI.

A biopsy is a procedure in which tissue samples are collected. This can be done with a needle, which is inserted into the abnormal area.
An example is the needle breast biopsy. Needle biopsies are usually guided by different imaging techniques like ultrasound, computed tomography, or magnetic resonance imaging. Stereotactic-assisted breast biopsies use computer maps to guide the needle. The location of the breast lump is provided from digital mammograms taken from two angles.
The cells can be removed and examined under a microscope to determine whether the abnormality is cancerous.

See also CT Guided Biopsy.

Breast imaging methods include mammography (mammogram), ultrasound, breast MRI, positron emission tomography, xeromammography, diaphanography and thermography.
Mammography is widely used as a screening method and diagnostic tool for breast cancer detection or evaluation of breast disease. Digital mammography takes multiple thin digital image 'slices' through the breast, which provides higher potential to see a small mass within dense tissue. The mammography quality standards act guarantees a high image quality.
Breast ultrasound (also called ultrasonography) should only be used as an additional imaging modality to evaluate specific breast abnormalities, especially to differentiate cystic from solid masses. Ultrasound is also used to guide needle breast biopsies.
Magnetic resonance imaging (MRI) is useful for breast MRI screening in cases of high cancer risk. In addition, multifocal breast cancer can be missed by standard practice mammography and can be early detected with breast MRI.