Medical application of neutron capture. gamma. -ray spectroscopy: measurement of cadmium and nitrogen in living human subjects. [/sup 113/Cd, /sup 14/N, /sup 15/N]
In-vivo measurement of small quantities of Cd is possible due to the high radiative neutron-capture cross-section of /sup 113/Cd (12.3%, 20000 b). Under slow neutron capture in /sup 113/Cd, the excited /sup 114/Cd decays by prompt emission of cascade of gamma-rays of which the most intense is the 559 keV transition from the first excited state to the ground state. For a total kidney or liver dose of 670 mrem, the detection limits are 2.5 mg or 1.5 ..mu..g/g respectively. A table shows the results of a study on normal subjects with smoking and non-smoking history. The study indicates higher cadmium levels in the group of smokers. The method of measuring body N utilizes the /sup 14/N(n,..gamma..)/sup 15/N reaction. The total energy available on slow neutron capture is 10.83 MeV and approximately 15% of the de-excitations take place directly to the ground state of /sup 15/N. The irradiation facility is basically the same as that described for measurement of Cd. The Cd collimator, however is replaced by a second collimator designed to provide a wide beam 13 x 60 cm at the level of the bed. During the irradiation the subject lies on a motorized bed which moves across the neutron beam. The precision or reproducibility of the measurements was performed using an Alderson phantom. For a standard 70 kg man having 2000 g of N, the accuracy of the measurement is +-2% with an error of 1.3% for reproducibility, based on several measurements over a 6-month period. The total radiation dose for a bilateral irradiation is 45 mrem. Initial clinical studies will concentrate on sequential measurements of body N.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 6777282
- Report Number(s):
- BNL-24711; CONF-780926-8
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
AEROSOLS
ANIMALS
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
CADMIUM
CADMIUM 113
CADMIUM ISOTOPES
CAPTURE
COLLOIDS
CRYOGENIC FLUIDS
DESIGN
DIGESTIVE SYSTEM
DISPERSIONS
DOSES
ELEMENTS
EVEN-ODD NUCLEI
FLUIDS
GAMMA SPECTROSCOPY
GLANDS
HADRON REACTIONS
INTERMEDIATE MASS NUCLEI
IRRADIATION DEVICES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KIDNEYS
LIGHT NUCLEI
LIVER
MAMMALS
MAN
MEASURING METHODS
METALS
MOCKUP
NEUTRON REACTIONS
NITROGEN
NITROGEN 14
NITROGEN 15
NITROGEN ISOTOPES
NONMETALS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANS
PHANTOMS
PRIMATES
RADIATION DOSES
RADIOISOTOPES
RESIDUES
SMOKES
SOLS
SPECTROSCOPY
STABLE ISOTOPES
STRUCTURAL MODELS
TOBACCO SMOKES
VERTEBRATES
YEARS LIVING RADIOISOTOPES