Strontium-90 Plesiotherapy

The Animal Medical Center, is pleased to announce the availability of Strontium-90 Plesiotherapy for dogs and cats. As a service to referring veterinarians, the following is a presentation of important information about the Strontium-90 Plesiotherapy treatment option.


Plesiotherapy involves the use of a radioactive probe to apply large single doses of radiation to superficial tumors. These probes were first developed to treat ocular lesions in people, but they have been found to be useful in treating a number of tumors in dogs and cats.


  • A strontium-90 probe has a radioactive source at the end of a rod which gives off low energy beta radiation. The probe can be used with a single application to treat small tumors or multiple overlapping treatments can be used to treat larger areas.
  • The radiation from a Strontium-90 probe only penetrates a few millimeters in the patient. This allows for a large dose of radiation to be applied to the skin or mucosa without affecting the deeper tissues. Most patients treated with Strontium-90 radiation develop an ulceration in the area which forms a scab and heals over time. These side effects rarely bother the patient.
  • The shallow depth of penetration of the radiation allows for treatment of small tumors in areas that are typically difficult to treat such as tumors of the cornea, sclera or eyelids.
  • Treatment usually is performed in a single treatment that typically takes less than 5 minutes. This means that patients need to be under anesthesia for a short period of time, minimizing the risk of potential complications.
  • In an article in the Journal of the American Veterinary Medical Association dermal mast cell tumors in cats treated using Strontium-90 were controlled 98 percent of the time. Many of the cats treated in this study had multiple tumors treated in a short treatment time.

The Animal Medical Center has a Strontium-90 probe for the treatment of superficial tumors in dogs and cats.