Biomaterial Database

A prompt gamma in vivo neutron activation analysis facility for measurement of total body nitrogen in the critically ill. 1984

A H Beddoe, and H Zuidmeer, and G L Hill

The quantitative assessment of the nutritionally-important components of body composition (protein, water and fat) provides a basic tool for research into the metabolic and nutritional problems of critically ill patients requiring intensive care. The construction and calibration of a facility that provides bilateral irradiation of patients with neutrons from two 281 GBq 238Pu-Be sources is described. Patients are scanned over a 36 min period, and composite prompt gamma-spectra are collected from two 5 in X 4 in NaI(Tl) detectors, placed on either side of the patient, using a conventional spectroscopy analysis system. A ratio of nitrogen to hydrogen counts corrected for body habitus and background is derived, from which protein can be estimated. This technique, combined with the measurement of water by tritium dilution, enables protein, water and fat to be estimated with precisions of 4.2%, 1.5% and 6.3% respectively, for a total dose equivalent (neutrons and tritium betas) of less than 0.5 mSv per examination.

UI	MeSH Term	Description	Entries
D009501	Neutron Activation Analysis	Activation analysis in which the specimen is bombarded with neutrons. Identification is made by measuring the resulting radioisotopes. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Activation Analysis, Neutron,Analysis, Neutron Activation,Activation Analyses, Neutron,Analyses, Neutron Activation,Neutron Activation Analyses
D009520	New Zealand	A group of islands in the southwest Pacific. Its capital is Wellington. It was discovered by the Dutch explorer Abel Tasman in 1642 and circumnavigated by Cook in 1769. Colonized in 1840 by the New Zealand Company, it became a British crown colony in 1840 until 1907 when colonial status was terminated. New Zealand is a partly anglicized form of the original Dutch name Nieuw Zeeland, new sea land, possibly with reference to the Dutch province of Zeeland. (From Webster's New Geographical Dictionary, 1988, p842 & Room, Brewer's Dictionary of Names, 1992, p378)
D009584	Nitrogen	An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
D001823	Body Composition	The relative amounts of various components in the body, such as percentage of body fat.	Body Compositions,Composition, Body,Compositions, Body
D003422	Critical Care	Health care provided to a critically ill patient during a medical emergency or crisis.	Intensive Care,Intensive Care, Surgical,Surgical Intensive Care,Care, Critical,Care, Intensive,Care, Surgical Intensive
D006757	Hospital Units	Those areas of the hospital organization not considered departments which provide specialized patient care. They include various hospital special care wards.	Hospital Unit,Unit, Hospital,Units, Hospital
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000201	Activation Analysis	A method of chemical analysis based on the detection of characteristic radionuclides following a nuclear bombardment. It is also known as radioactivity analysis. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Analysis, Activation,Activation Analyses,Analyses, Activation