Predictive value of tracer studies for /sup 131/I treatment in hyperthyroid cats

Journal Article · Mon Feb 01 04:00:00 EST 1988 · Am. J. Vet. Res.; (United States)

OSTI ID:5201778

Broome, M R; Turrel, J M; Hays, M T

In 76 cats with hyperthyroidism, peak thyroidal radioiodine (/sup 131/I) uptakes and effective half-lives were determined after administration of tracer and therapeutic activities of /sup 131/I. In 6 additional hyperthyroid cats, only peak thyroidal uptakes after administration of tracer and therapeutic activities of /sup 131/I were determined. Good correlation was found between peak thyroidal uptakes of tracer and therapeutic /sup 131/I; however, only fair correlation was observed between effective half-lives. In 79% of the cats, the effective half-life for therapeutic /sup 131/I was longer than that for tracer /sup 131/I. After administration of therapeutic activity of /sup 131/I, monoexponential and biphasic decay curves were observed in 51 and 16 cats, respectively. Using therapeutic kinetic data, radiation doses to the thyroid gland were calculated retrospectively on the basis of 2 methods for determining the activity of /sup 131/I administered: (1) actual administration of tracer-compensated activity and (2) hypothetic administration of uniform activity (3 mCi). Because of the good predictive ability of tracer kinetic data for the therapeutic kinetic data, the tracer-compensated radiation doses came significantly (P = 0.008) closer to the therapeutic goal than did the uniform-activity doses. In addition, the use of tracer kinetic information reduced the extent of the tendency for consistently high uniform-activity doses. A manual method for acquiring tracer kinetic data was developed and was an acceptable alternative to computerized techniques. Adoption of this method gives individuals and institutions with limited finances the opportunity to characterize the iodine kinetics in cats before proceeding with administration of therapeutic activities of /sup 131/I.

• Research Organization: Univ. of California, Davis (USA)
• OSTI ID: 5201778
• Journal Information: Am. J. Vet. Res.; (United States), Journal Name: Am. J. Vet. Res.; (United States) Vol. 49:2; ISSN AJVRA
• Country of Publication: United States
• Language: English

Related Subjects

550604* -- Medicine-- Unsealed Radionuclides in Therapy-- (1980-)
560162 -- Radionuclide Effects
Kinetics
& Toxicology-- Animals
Plants
Microorganisms
& Cells
62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL HALF-LIFE
BODY
CATS
DAYS LIVING RADIOISOTOPES
DISEASES
DOSES
ENDOCRINE DISEASES
ENDOCRINE GLANDS
GLANDS
HYPERTHYROIDISM
INTERMEDIATE MASS NUCLEI
IODINE 131
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEDICINE
NUCLEAR MEDICINE
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIATION DOSES
RADIOISOTOPES
RADIOLOGY
RADIONUCLIDE KINETICS
RADIOTHERAPY
THERAPY
THYROID
TRACER TECHNIQUES
UPTAKE
VERTEBRATES