(DR) Digital radiography uses a special electronic x-ray detector, which converts the radiographic image into a digital picture for review on a computer monitor. The digital image is then stored and can be post processed by changing the magnification, orientation, brightness, and contrast. Digital radiography (also called direct radiography) is a progressive development of computed radiography (CR).
These advantages can lead to fewer 'recalls' (repeated x-ray images) including a lower radiation dose than analog or conventional radiography. DR and CR systems use no chemicals to process the x-ray images and the hazardous materials and waste associated with film development are eliminated.

Advantages of digital radiography compared with conventional radiography:

Direct exposure films are highly sensitive to the direct effect of x-rays rather than in combination with an intensifying screen. However, a film is a relatively inefficient radiation detector and requires relatively high radiation exposure. The use of rectangular collimation and the highest speed films reduce radiation exposure.

See also Conventional Radiography.

A distributed source is a one dimensional area or volume source compared to the dimensions of the detector and which may produce a radiation beam over a wide range of angles of incidence on the measurement area.

The industry standard of computed tomography (CT) contrast media power injectors changed over time from single-head to dual-head systems. The advantage of a power (or pressure) injector with two syringes is that a saline solution can be injected first to open the veins, followed by a second injection with contrast agent. Then the first head flushes the saline to maintain contrast flow. As a result, much less contrast agent is needed (about 30 percent less), helping to reduce costs. Dual-head contrast media injectors also provide greater patient safety by reducing the pressure of the flow rate, helping to prevent damage to the veins.
Contrast delivery is much more controlled and efficient when using a dual-head power injector (also called double-piston injector). Also, these medical devices are required to accommodate the quick imaging times typical for a multi-detector CT scanner.

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

The dynamic range describes the range of x-ray intensities a detector can differentiate. A high dynamic range provides the discrimination between small differences in x-ray attenuation.
A current CT scanner has approximately a dynamic range of 1,000,000 to 1 and 1,100 views or projections a second.