Hologic, Inc. is a medical technology company primarily focused on women's health; it sells medical devices for diagnostics, surgery, and medical imaging. The company was founded in 1985 by S. David Ellenbogen (1938-2001) and Jay A. Stein (1942-) in Bedford, Massachusetts. Ellenbogen graduated from Newark College of Engineering, and Stein received a Ph.D. in physics from the Massachusetts Institute of Technology.

Mammography is a technique that uses x-rays to diagnose and locate breast cancer. For many years, the "gold standard" for diagnosing breast cancer was film mammography, an x-ray-based technology designed to screen for breast cancer in women with no signs or symptoms. In 1973, the DuPont Company was the first to market a dedicated mammography system and emerged as the leader in selling film-based x-ray mammography systems.

At the time, Hologic was most known for its instruments for measuring bone density. Sterling Diagnostic Imaging, a leading x-ray film and equipment provider, had already sold off one-third of its business earlier the same year. The digital x-ray portion was called Direct Radiography Corp. X-ray technology produced digital images rather than film, a technology that was spun off from the DuPont Company's digital radiography technology, which Sterling Diagnostic Imaging acquired in 1996.

In 2000, the Food and Drug Administration (FDA) approved the sale of the first digital mammography systems in the United States. DuPont had sold off its x-ray film business and patents related to digital radiology and mammography by that time.

The first digital mammography could only provide a two-dimensional picture of the breast. Although a 2-D image was suitable for assessing fatty breast tissue, it has difficulty picking up abnormalities in dense breast tissue, and overlapping tissue in the image sometimes makes it hard to see tiny micro-calcifications and other subtle signs of early cancer.

Tomosynthesis is a 3-D mammography tool that uses a digital x-ray high-power computer to convert 2-D digital breast images into a stack of very thin layers or "slices" into a three-dimensional image. With breast tomosynthesis technology, the radiologist can examine complexities a millimeter at a time in breast tissue.

In 1999, Hologic bought the digital x-ray business Direct Radiography Corp. from Sterling Diagnostic Imaging, Inc., located in General Electric (GE), which was the first company to gain commercial approval for a digital mammography detector. Through the acquisition Hologic added DirectRay flat-panel digital x-ray, EPEX, and Radex general radiography systems into its product line. For more than two years, GE had the U.S. digital mammography market all to itself. In 2002, the FDA approved the Hologic digital mammography system.

In 2008, Hologic introduced breast tomosynthesis in many of the countries recognizing the CE mark (indicating a product's compliance with European Union legislation). In 2011, Hologic got FDA approval and introduced tomosynthesis in the U.S. Hologic was the only provider of tomosynthesis systems allowed to sell in the U.S. for the next three years.