In the small percentage of dogs who develop a thyrotoxicosis secondary to a differentiated thyroid neoplasia, diagnosis can be aided by measurement of circulating thyroid hormone levels. Technetium pertechnetate is concentrated in thyroid tissue by the same mechanism as iodine. By evaluating the uptake of technetium pertechnetate on a thyroid scintigraphy it is possible to better define the nature and extent of thyroid neoplasia. Thyroid scintigraphy is an important step in the staging of the canine patient with differentiated thyroid neoplasia. Most veterinary literature describes the use of surgery or surgery combined with chemotherapy for the treatment of thyroid carcinoma.
Surgery is a very important part of the therapy for differentiated thyroid carcinoma.
This prevents a surgical cure for these patients. Currently available chemotherapy for canine thyroid carcinoma has been disappointing. The basis for radioiodine therapy is the unique ability of thyroid cells to concentrate iodine. This capability allows differentiated thyroid carcinoma cells to preferentially concentrate radioactive iodine administered to dogs with persistent disease following surgical debulking. Because the radioiodine is only concentrated by thyroid cells, the remainder of the dog's body is spared the effects of the radiation.