Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using (153)Sm, (90)Y, and (117m)Sn

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: (153)Sm-1,4,7,10-tetraazacylcododecanetetramethylenephosphonic acid, which is a bone-seeking radiopharmaceutical; unencapsulated (90)Y permanent interstitial implants, which are sometimes called “liquid brachytherapy”; and (117m)Sn radiosynoviorthesis, which is also called radiosynovectomy. External exposure rate readings of the (153)Sm and (117m)Sn treatments, and Monte Carlo simulations of (117m)Sn 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 (90)Y interstitial implant or for a month following (117m)Sn radiosynoviorthesis. No such avoidance is necessary after treatment with (153)Sm-1,4,7,10-tetraazacylcododecanetetramethylenephosphonic acid.