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.

(m) The SI base unit of distance.
Definition: 1983 defined as the distance traveled by light in a vacuum during the time interval of 1/299 792 458 of a second.
The speed of light in a vacuum, c, is one of the fundamental constants of nature.

1 meter (m) is equal to approximately 39.370 079 inches (in)
1 meter is equal to approximately 3.280 840 feet (ft)
1 meter is equal to approximately 1.093 613 3 yard (yd)
1 square meter (m²) is equal to approximately 10.763911 square feet (ft²)
1 inch = 2.54 centimeters
Smaller or larger units are, e.g.:
1 meter (m) = 1 000 millimeter (mm)
1 micrometer (µm) = 10^-6 meter (m)
1 nanometer (nm) = 10^-9 meter (m)
1 picometer (pm) = 10^-12 meter (m)
1 femtometer (fm) = 10^-15 meter (m)
1 kilometer (km) = 1 000 meter (m)
1 kilometer (km) = 0.62137 (statute) miles (mi)

See also System International.

Multi-head contrast media injectors offer flexible contrast media management, simplified workflows and increased patient safety.
Contrast delivery is much more controlled and efficient when using a dual-head CT power injector. These medical devices are needed to enable the short imaging times typical of multidetector computed tomography (CT) scanners.
Triple-head injectors allow selection of a second contrast agent when two different contrast agents are used, or switching to full contrast agent containers when two identical contrast agents are used.

See also Contrast Media Injector, Syringeless CT Power Injector, Single-Head Contrast Media Injector, CT Power Injector.

(N) The SI unit of force.
Definition: 1 newton will accelerate a mass of 1 kilogram at the rate of 1 meter per second.
The relationship between force (F), mass (m), and acceleration (a) is expressed by the formula: F = ma.
The newton is named for Isaac Newton (1642-1727), the British mathematician, physicist, and natural philosopher.

If available, some graphic aids can be helpful to show image orientations.
1) A graphic icon of the labeled primary axes (A, L, H) with relative lengths given by direction sines and system of coordinates as if viewed from the normal to the image plane can help orient the viewer, both to identify image plane orientation and to indicate possible in plane rotation.
2) In graphic prescription of obliques from other images, a sample original image with an overlaid line or set of lines indicating the intersection of the original and oblique image planes can help orient the viewer. The location in the R/L and P/A directions can be specified relative to the axis of the scanner.
The F/H location can be specified relative to a convenient patient structure.
The orientation of single oblique slices can be specified by rotating a slice in one of the basic orientations toward one of the other two basic orthogonal planes about an axis defined by the intersection of the 2 planes.
Double oblique slices can be specified as the result of tipping a single oblique plane toward the remaining basic orientation plane, about an axis defined by the intersection of the oblique plane and the remaining basic plane. In double oblique angulations, the first rotation is chosen about the vertical image axis and the second about the (new) horizontal axis. Angles are chosen to have magnitudes less than 90° (for single oblique slices less than 45°); the sign of the angle is taken to be positive when the rotation brings positive axes closer together.