Artikel Thyroidal radioisotope uptake in euthyroid cats : a comparison between 131 I and 99 MTcO

INTRODUCTION The use of radionuclides for evaluating thyroid conditions in cats is well documented. Hyperthyroidism is the most common indication. A feature of hyperthyroidism is an increased uptake of radionuclide. The radionuclides most frequently used for thyroidal imaging are I, I, and the pertechnetate ion of technetium (TcO4). The radioisotopes of iodine are exclusively taken up by the thyroid gland. TcO4, in addition to being concentrated in the thyroid gland, is also concentrated in the salivary and sweat glands, choroid plexus and gastric mucosa. I is used least frequently in veterinary medicine owing to its high cost and limited availability The purpose of this study was to compare 2 thyroidal uptake evaluation systems in euthyroid cats. Radioiodine uptake measurement (RAIU) using I in combination with a standard thyroid uptake system (TUS) was compared to an uptake estimated from the ratio of thyroid to salivary activities (T/S) of TcO4 using a scintillation camera. A single, confirmed hyperthyroid cat was included to add interest to the study.