mammography
Meaning of mammography: No screening test is purely beneficial, and mammography programs are judged on the balance between cancers found early and abnormalities that never needed finding.
Definition of mammography
Mammography is the imaging technique that uses low energy x-rays to picture the internal structure of the breast. It exists in several forms: film mammography recorded on sheets of x-ray film, digital mammography captured electronically, and tomosynthesis, which builds a stack of thin slices from images taken at several angles.
How mammography is built
- mamm/o, mast/o Combining form · Latin and Greek breast
- -graphy Suffix · Greek the process of recording or imaging
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
How does the technique work?
Breast tissue is soft throughout, so the density differences that create contrast on an ordinary x-ray are very small. Mammography answers that with x-rays of lower energy than general radiography uses, which exaggerate the small differences between fat, fibrous tissue and anything abnormal. Compression supplies the other half of the answer: flattening the breast reduces the thickness the beam passes through, pulls overlapping structures apart, holds the tissue still, and lowers the dose needed to produce a usable image. The dose from a single examination is small, comparable to a few weeks of the radiation everyone receives from the natural environment.
Film, digital or three dimensional?
| Form | How the image is captured | Notes |
|---|---|---|
| Film mammography | Exposed onto x-ray film and chemically developed | The original method, now largely replaced |
| Digital mammography | Captured on an electronic detector | Images can be adjusted, stored and compared easily, and it performs better in dense tissue |
| Tomosynthesis | Several exposures at different angles, reconstructed into slices | Reduces the problem of overlapping tissue, finding more cancers and recalling fewer people |
| Contrast enhanced mammography | Digital images taken after an iodine based contrast injection | Highlights areas with an increased blood supply |
What are the limits, and what else is used?
Mammography misses some cancers, most often in dense tissue, and it finds abnormalities that would never have caused harm, leading to further tests and sometimes to treatment that was not needed. Those two facts sit at the center of the long running argument about how screening programs should be organized, and they are why the age at which screening begins and how often it repeats differ between countries and are revised as evidence changes. Other methods fill different gaps. Ultrasound separates a fluid filled cyst from a solid mass and guides needle sampling. Magnetic resonance is the most sensitive of all and is used for people at high risk and for mapping the extent of a known breast cancer, though it also flags more findings that turn out to be harmless. None of these replaces mammography, because none matches its ability to show calcifications.
Used in a sentence
The patient's annual mammography showed no evidence of a new or changing mass.
Good to know
Screening mammography is performed in people without symptoms to look for early disease while diagnostic mammography evaluates a specific finding, and the two differ in the images taken and in how quickly the results are acted on.
Word origin
Where “mammography” comes from
Formed from Latin mamma, meaning breast, and Greek graphein, meaning to write or record.