December 20, 2001

AGENCY INFORMATION NOTICE 01-02: CONTROL OF RELEASE OF RADIOACTIVE MATERIALS TO SOLID WASTE OR TRASH PROCESSING FACILITIES FROM VETERINARY MEDICAL PROCEDURES (TREATMENT OF DOMESTIC CATS WITH IODINE-131 FOR HYPERTHYROIDISM)

Background

Recent successes in the radiotherapy of domestic cats using iodine-131 for the treatment of hyperthyroidism has resulted in increasing numbers of cat owners seeking this treatment for their pets. In addition, an increasing number of solid waste or trash facilities have installed radiation monitors at their entrance gates to prevent "orphan", lost or discarded sources of ionizing radiation from being handled in a manner that results in increased radiation dose to the workers and to the community. The result has been an increasing number of radiation monitor alarms at solid waste transfer, treatment and disposal facilities across the Commonwealth of Massachusetts. These alarms have resulted in costly expenditures of labor for the cities and towns in isolating and analyzing the radioactive materials, for the solid waste businesses and for the Agency. The costs of reshipping tons of solid waste and the loss of the use of trucks and trailers during the investigation process are also substantial. The following actions by licensees are required to reduce the number of alarm activations.

Actions

All licensees authorized to treat domestic cats for hyperthyroidism using iodine-131 will therefore immediately modify their procedures as follows:

  • All written cat owner instructions will be modified to require the use of flushable cat litter by all cat owners for a period of at least two (2) weeks following the release of the cat to the owner. There are manufacturers of cat litter that have tested their products and have determined that these products are safe for both sewerage and septic sanitary waste systems. The veterinarian will ensure that a source of an acceptable product is identified to the owner before discharge of the animal.

  • The cat owner will agree in writing to the use of flushable litter for a period of at least two (2) weeks following release from the hospital. Otherwise, the veterinarian will require that the cat be boarded at the clinic for that period or until the radiation field from the cat has returned to background whichever is earlier.

  • The veterinarian will not discharge the cat until the average radiation field at one (1) meter from the cat has been reduced to 0.5 millirem per hour or less.

NOTE: The Agency is not specifying a specific boarding period for the animal because the dose rate at one meter will vary significantly from animal to animal depending on initial dose, condition of the cat, degree of hydration and the amount of water ingested. This Information Notice is subject to modification at any time depending on its impact on the control of radiation events at solid waste or trash processing facilities in the Commonwealth.

Sincerely,

ORIGINAL SIGNED BY ROBERT M. HALLISEY
Robert M. Hallisey, Director
Radiation Control Program


This information is provided by the Radiation Control Program within the Department of Public Health.