Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using ¹⁵³Sm, ⁹⁰Y, and ^117mSn

The treatment of pets, service animals, and pre-clinical research subjects with radionuclides raises concern for the safety of the people who interact with the animals after their treatment. Three treatments of skeletal conditions in dogs are considered in this study: 153Sm-1,4,7,10-tetraazacylcododecanetetramethylenephosphonic acid, which is a bone-seeking radiopharmaceutical; unencapsulated 90Y permanent interstitial implants, which are sometimes called "liquid brachytherapy"; and 117mSn radiosynoviorthesis, which is also called radiosynovectomy. External exposure rate readings of the 153Sm and 117mSn treatments, and Monte Carlo simulations of 117mSn at a distance of 1 m and of all three in direct contact with tissue were analyzed for doses. Dogs that have received any of these treatments using typically administered activities may be released from radiation safety isolation immediately after treatment from the standpoint of external exposure. People should avoid prolonged close proximity, such as sleeping with a treated dog, for three weeks following an 90Y interstitial implant or for a month following 117mSn radiosynoviorthesis. No such avoidance is necessary after treatment with 153Sm-1,4,7,10-tetraazacylcododecanetetramethylenephosphonic acid.