Beta radiation consists of high energetic electrons or positrons emitted spontaneously from nuclei in decay of some radionuclides. Also called beta particle and sometimes shortened to beta (e.g., beta-emitting radionuclides). Beta radiation is used for example in cancer treatment.
The average reach of beta radiation in tissue is 3.5 mm.

See also Beta Decay.

The phase of software testing where a program or system is turned over to a select group of users outside the development organization for use in real-life situations.

See also Alpha Test.

The molecular structure of some iodinated contrast agents makes them suitable for the computer-tomographic examination of the biliary tract. Organic iodine compounds increase the attenuation of x-rays and the contrast between body tissues containing iodine and those tissues that do not contain iodine. The degree of opacification is directly proportional to the concentration and volume of the iodinated contrast agent (the total amount of iodine).
Biliary contrast agents can be taken orally, for example calcium iopodate, or intravenous meglumine iotroxate. The contrast media are excreted by the liver and concentrate in the gallbladder after passing the intrahepatic biliary tree and cystic duct.
Oral biliary contrast agents usually opacify the gallbladder after a few hours. If the gallbladder is removed, an intravenous cholegraphic agent is required and gallbladder CT can start 60 minutes after the beginning of contrast medium infusion.
The main limitation of the use of biliary contrast agents is the high rate of allergic reactions and of renal or hepatic toxicity. Caused by the potential for systemic toxicity with intravenous cholangiography, ultrasonography should be the preferred method for evaluation of the gallbladder and the bile ducts.

Biliscopin® Infusion, an iodinated contrast medium for intravenous cholecystography is secreted actively by the hepatocytes. The biliary excretion rate of a biliary contrast medium is determined by the binding to plasma proteins and liver receptor proteins, and by its transport maximum for the liver. Because of its high hepatocellular transport rate, Biliscopin® Infusion leads rapidly to high grade contrast density in the intra-hepatic and extra-hepatic biliary ducts as well as in the gallbladder.
Computed tomography with biliary contrast agents provides maximum quality preoperative imaging of the biliary tract.

[Binary Numeral System] Numerical system based on two different states, usually represented by the two symbols 0 and 1. Information storage and processing in modern computers is based on this system. Here the smallest unit is a bit.

See Bit, Byte.