(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:

Different stages of the drug development and approval process in the USA, lead from preclinical trials (testing in animals), first application in humans through limited and broad clinical tests, to postmarketing studies.

	Years	Test Population	Purpose	Success Rate
Preclinical Testing	3.5	Laboratory and animal studies	Assess safety and biological activity	5,000 compounds evaluated
File IND at FDA
Phase I	1	20 to 80 healthy volunteers	Determine safety and dosage	5 enter trials
Phase II	2	100 to 300 patient volunteers	Evaluate effectiveness, look for side effects
Phase III	3	1000 to 3000 patient volunteers	Verify effectiveness, monitor adverse reactions from long-term use
File NDA at FDA
FDA	2.5	Review process / Approval		1 approved
	12 Total
Phase IV	Additional Post marketing testing required by FDA

By Dale E. Wierenga, Ph.D. and C. Robert Eaton
Office of Research and Development
Pharmaceutical Manufacturers Association

'In reviewing this report, it is important to keep in mind the realities of the drug discovery and development process. The U.S. system of new drug approvals is perhaps the most rigorous in the world. On average, it costs a company $359 million to get one new medicine from the laboratory to the pharmacist's shelf, according to a February 1993 report by the Congressional Office of Technology Assessment.'

See also Phase 1 2 3 4 Drug Trials, Clinical Trial, Food and Drug Administration, and European Medicines Agency.

Gas chromatography is a process to separate gas molecules of different size due to their different adsorption at macroporous surfaces, e.g. at activated charcoal. The separation is managed by the use of starting gas or heating up.

Image resolution is a measurement of the scanned, printed, or displayed image quality. Picture resolution on a printed photo or page is measured in dots per inch (DPI). For digital files, image resolution is expressed in pixels per inch (PPI).
The quality of pixel-based images is directly determined by resolution choices. Higher image resolution results in more detailed images but requires more storage space in a picture archiving and communication system.
The resolution for x-ray images can be defined as the period length of the finest grid that can be viewed without difficulty.

Radiation can ionize matter caused by the high energy which displaces electrons during interactions with atoms. In the electromagnetic spectrum higher frequency ultraviolet radiation begins to have enough energy to ionize matter.
Examples of ionizing radiation include alpha particles, beta particles, gamma rays, x-rays, neutrons, high-speed electrons, high-speed protons, and other particles capable of producing ions by direct or secondary processes in passage through tissues.
Damage of living tissue results from the transfer of energy to atoms and molecules in the cellular structure. Ionized cells have to repair themselves to remain alive. Generally, healthy cells have a higher capability to repair themselves than cancer cells.

Biological effects of ionizing radiation exposure:
Ionizing radiation are used in a wide range of facilities, including health care, research institutions, nuclear reactors and their support facilities, and other manufacturing settings. These radiation sources can pose a serious hazard to affected people and environment if not properly controlled.

See also Radiation Safety, Controlled Area, Radiotoxicity and As Low As Reasonably Achievable.