Retention and skeletal dosimetry of injected /sup 226/Ra, /sup 228/Ra, and /sup 90/Sr in beagles
Total-body retention has been determined by in vivo counting in beagles injected with /sup 226/Ra (125 dogs), or /sup 228/Ra (78 dogs), or /sup 90/Sr (96 dogs). The radionuclides were administered intravenously in a citrate buffer solution when the animals were about 1.4 years of age. Retention measurements now extend to more than 14 years after injection; therefore, future revision of these retention equations appears unlikely since the median lifespan in our control beagles is about 12.7 years. Dogs injected with about 10 ..mu..Ci /sup 226/Ra/kg had a higher long-term retention than those receiving 0.04 to about 4 ..mu..Ci /sup 226/Ra/kg. The /sup 228/Ra retention data were not analyzed numerically, but visual inspection of the curves prepared for individual dogs indicated that /sup 228/Ra retention could be described adequately by the retention equation derived for dogs given 0.04 to 4 ..mu..Ci /sup 226/Ra/kg. The average skeletal radiation dose rate and cumulative radiation dose were calculated for each beagle injected with /sup 226/Ra, /sup 228/Ra, or /sup 90/Sr using the appropriate retention equation, normalized to each dog's individual retention measurements. Allowance was made in the /sup 226/Ra calculations for the changing skeletal retention of /sup 222/Rn and its radioactive daughters; in the /sup 228/Ra calculations for the diminution of /sup 228/Ra activity by radioactive decay as well as for the ingrowth and skeletal retention of /sup 228/Th and its radioactive daughters; and in the /sup 90/Sr calculations for the diminution of /sup 90/Sr concentration by radioactive decay and the escape of ..beta..-energy from bone. The half-time (4621 days) of the longest-lived component in the /sup 90/Sr retention equation was similar to that for the lower-level Ra dogs. This may reflect the net remodeling rate of cortical bone in the beagle skeleton.
- Research Organization:
- Univ. of Utah, Salt Lake City
- OSTI ID:
- 7362326
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 66:2; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
ANIMALS
BEAGLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
DOGS
DOSE-RESPONSE RELATIONSHIPS
DOSIMETRY
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPES
MAMMALS
NUCLEI
ORGANS
RADIOISOTOPES
RADIONUCLIDE KINETICS
RADIUM 226
RADIUM 228
RADIUM ISOTOPES
RETENTION
SKELETON
STRONTIUM 91
STRONTIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES