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Radiation dose to veterinarians and veterinary technicians during performance of radioiodine treatment of Felis catus




Dieffenthaller, Meghan Marie, author
Johnson, Thomas, advisor
Sudowe, Ralf, committee member
Pagliassotti, Michael, committee member

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The purpose of this project is to determine I-131 uptake of veterinarians or veterinary staff when radioiodine (I-131) is administered via injection to domesticated cats (Felis catus) with hyperthyroidism. Currently, veterinarians and staff perform a bioassay either every three months or if they have administered a cumulative 10 mCi of I-131. Veterinarians and staff undergo specific training for the handling of radioiodine injection of cats to minimize and prevent an intake. A bioassay is performed post cat injection to determine if I-131 was inhaled or absorbed. The frequency of these bioassays requires dedicated time of the veterinarians and those who must perform the bioassay. Bioassay data from veterinarians and staff at the Colorado State University Veterinary Teaching Hospital (CSU VTH) administering I-131 from the past 20 years were analyzed to ascertain if there is a correlation between the amount of time elapsed between the I-131 administration and the bioassay and the net counts resulting from the bioassay. The amount of I-131 administration and the bioassay net counts were also analyzed to determine if there was a correlation. No correlations were found, and out of 168 I-131 administrations over 20 years, only 7 bioassays showed measurable doses of I-131 of a committed dose equivalent (CDE) of 5.71 mrem (n=1), 7.53 mrem (n=2), 10.9 mrem (n=1), 20.7 mrem (n=1), and 75.1 mrem (n=2). The current precautions taken to prevent the intake of I-131 appear sufficient enough to allow for less frequent bioassays.


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thyroid tumor


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