title: Whole body measurement of C, N and O using 14 MeV neutrons and the associated particle time-of-flight technique.
abstract: Our aim has been to construct a portable prototype instrument for measuring the whole body composition in vivo of growing lambs in terms of fat. protein and water by determining the mass of carbon, nitrogen and oxygen present. A small and compact sealed tube neutron generator which has the capability of exploiting the associated particle time-of-flight technique has been used for prompt gamma 14 MeV neutron activation analysis of C, N and O. This technique allows only gamma rays generated by neutron reactions within a defined volume to be recorded and offers a superior signal-to-noise ratio over existing prompt gamma neutron activation techniques. Based on the results obtained from irradiating a 41.4 kg meat phantom, we anticipate that an instrument comprising the neutron generator and four 15 x 15 x 45 cm Nal(TI) gamma ray detectors can be assembled to determine in vivo, protein, fat and water with precisions of 4.1, 5.4 and 1.2% (CV), respectively, within a 15 min scan. The radiation dose delivered would be ~0.03 mSv.
authors.affiliation: Growth Physiology Group, AgResearch, Ruakura, Hamilton, New Zealand.
authors.forename: S
authors.initials: S
authors.lastname: Mitra
authors.forename: J E
authors.initials: JE
authors.lastname: Wolff
authors.forename: R
authors.initials: R
authors.lastname: Garrett
authors.forename: C W
authors.initials: CW
authors.lastname: Peters