QUANTITATIVE TC-99M-PERTECHNETATE THYROID SCINTIGRAPHY IN NORMAL BEAGLES

This study was done to investigate the validity of published canine th yroid/salivary (TIS) ratios of approximately 1 in normal dogs and to d etermine thyroid uptake of Tc-99m-pertechnetate (pertechnetate) measur ed as percent uptake of injected dose, These parameters were evaluated in 13 Beagle dogs over a 4 hour period, Mean +/- standard deviation ( SD) and median TIS ratios of 1.2 +/- 0.3 and 1.1 were essentially the same at twenty minutes and 1 hour, T/S values ranged from 0.9 to 2.2 a t 20 minutes and from 0.8 to 2.4 at 1 hour. TIS ratio values progressi vely declined over the subsequent time intervals with mean +/- SD and median values of 0.6 +/- 0.2 and 0.6, respectively, measured at 4 hour s, The mean +/- SD maximum percent dose uptake of pertechnetate within the thyroid gland was 0.55% +/- 0.15% with a range of 0.28% to 0.90%, The mean +/- SD time interval from injection of pertechnetate to maxi mum uptake within the thyroid gland was 160 +/- 55 minutes with a rang e 31-240 minutes, The data derived from this study of normal dogs may be useful in the evaluation of dogs with thyroidal diseases including hypothyroidism.