Becquerel unit

BBN bcc bp bpy Bq "Bu 9-borabicyclo[3.3.1]nonane body-centred cubic boiling point 2,2 -bipyridine becquerel (unit of radioactivity) w-butyl DME DMF dmgH2 DMSO DNA dimethoxyethane iV,A-dimethylformamide dimethylglyoxime dimethylsulfoxide deoxyribonucleic acid... 

The earlier literature references and some of the older textbooks in radiochemistry naturally used the older units. Even now many practicing scientists have not adopted the SI units that were recommended as the standardization of names and symbols by many international scientific bodies. Curie and Becquerel units have be often found used exchangeably in literature for radiation activities. 

Ra.dia.tlon Units. Units in use for activity of a radionucHde, ie, the curie, the roentgen (exposure to x and gamma rays), the rad (absorbed dose), and the rem (dose equivalent), should eventually be replaced by the becquerel (Bq), coulomb per kilogram (C/kg), gray (Gy), and the sievert (Sv), respectively. 

The activity of a sample, source or contaminated material is the rate at which radioactive disintegrations are taking place. The initial term, named by Madam Curie for her husband was, the Curie (Table 8.3-1). The modem unit is the Becquerel named after the discoverer of... 

Curie (Ci) A unit of radioactivity, related to the emission from 1 g of radium, it is equal to 3.7 x 10 disintegrations per gram per second. This unit has been replaced by the Becquerel (Bq) 1... 

Quantities of americium, as well as other radioactive elements, are measured in units of mass (grams) or radioactivity (curies or becquerels). The becquerel (Bq) is a new international unit and... 

Activity—The number of radioactive nuclear transformations occurring in a material per unit time (see Curie, Becquerel). The term for activity per unit mass is specific activity. 

Becquerel (Bq)—International System of Units unit of activity and equals that quantity of radioactive material in which one transformation (disintegration) occurs per second (see Units). 

SI Units—The International System of Units as defined by the General Conference of Weights and Measures in 1960. These units are generally based on the meter/kilogram/second units, with special quantities for radiation including the becquerel, gray, and sievert. 

The SI unit of activity is the becquerel (Bq) 1 Bq = that quantity of radioactive material in which there is 1 transformation/second. Since activity is proportional to the number of atoms of the radioactive material, the quantity of any radioactive material is usually expressed in curies, regardless of its purity or concentration. The transformation of radioactive nuclei is a random process, and the number of transformations is directly proportional to the number of radioactive atoms present. For any pure radioactive substance, the rate of decay is usually described by its radiological half-life, TR, i.e., the time it... 

The ICRU (1980), ICRP (1984), and NCRP (1985) now recommend that the rad, roentgen, curie, and rem be replaced by the SI units gray (Gy), Coulomb per kilogram (C/kg), Becquerel (Bq), and sievert (Sv), respectively. The relationship between the customary units and the international system of units (SI) for radiological quantities is shown in Table D-5. 

The radioligand should also have a high specific activity so that very small quantities of bound ligand can be accurately measured. The specific activity, simply defined as the amount of radioactivity, expressed in becquerels (Bq) or curies (Ci) per mole of ligand, is dependent on the half-life of the isotope used and on the number of radioactive atoms incorporated into the ligand molecule. A radioisotope with a short half-life decays rapidly so that many disintegrations occur in unit time,... 

Activity The activity of a radioactive material is the number of nuclear disintegrations per unit time. Up to 1977, the accepted unit of activity was the curie (Ci), equivalent to 37 billion disintegrations/s, a number that approximated the activity of 1 g radium-226. The present unit of activity is the becquerel (Bq), equivalent to 1 disintegration/s. 

Becquerel (Bq) The presently accepted unit of activity is the becquerel, equivalent to 1 disintegration/s. About 0.037 Bq = 1 picocurie. 

The System Internationale (SI) unit for radioactivity is becquerel (Bq), which is defined as one disintegration per second. The SI units and the conversion factors between curie and SI units are listed in Table 15.2. 

Radiopharmaceuticals are prescribed according to units of radioactivity. A pharmacist practicing nuclear pharmacy may need to convert radio activity units from curies to SI unit, becquerel and its multiples, and vice versa. The following examples illustrate the interconversion of radioactive units. 

The curie unit (Ci) is based on the activity of 1 g of pure radium-226, which undergoes 3.7 X 1010 transformations per second. It is therefore defined as the quantity of a radioactive isotope which gives 3.7 X 1010 disintegrations per second. The SI unit of activity is the becquerel (Bq), which is equal to one nuclear transformation per second. Hence ... 

The specific activity of an isotope indicates the activity per unit mass or volume and is quoted as becquerels per gram (Bq g-1) or millicuries per gram (mCi g-1). A sample in which all the atoms of a particular element are radioactive is said to be carrier-free and is very difficult to achieve in practice. 

The SI unit of measure for radioactivity. One becquerel (Bq) is equal to one disintegration per second (dps), thereby corresponding to about 2.703 x 10 curie. 

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