The display matrix is the matrix in the displayed image and can be equal to or larger than the reconstruction matrix size due to interpolation procedures. This array of rows and columns of pixels is typically between 512 x 512 and 1024 x 1024.

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.

E-Z-CAT Dry is a dry CT barium contrast powder for suspension and can be mixed and self-administered at home. This may improve examination throughput, reduces patient waiting time and help to minimize waiting room congestion. The light E-Z-Cat® Dry foil packets can also be mailed to patients in remote locations.
The oral contrast agent is well compatible with new scanner technologies and provides a fast transit time through the GI tract.

An electromagnetic lens is designed to focus the electron beam by using a suitable shaped magnetic field. The lens is a symmetric electromagnet consisting of wire coil, magnetic iron yoke and iron pole pieces. A strong magnetic field is produced by passing a current through the windings. This field acts as a convex lens; converge off axis rays back to focus. Like an optical lens, a magnetic lens is characterized by focal length and can be altered by changing the strength of the current.

(K-capture) An unstable atom with too many protons in the nucleus, and not enough energy to emit a positron, reaches a stable state in the way, that one proton captured an electron from the atom's inner shell (K-shell) and change to a neutron. A neutrino is emitted from the atoms nucleus by this process. The atomic mass of the atom is unchanged, but the decreased number of protons transformed the atom to a different element.