RESUMO
Objective A new type of double-tube standard source load model provides better simulation of the human thyroid than does a traditional single-tube standard source load model. The radioactive counts of these two models were compared, as were their impacts on thyroid iodine-131 (13lI) uptake rates. Methods A double-tube standard source load model was used to analyze its impact on the rates of 131I uptake by the subjects' thyroid glands, and to compare the results with those obtained using a single-tube standard source load model. Radioactive counts in different positions were measured by thyroid function instruments, and compared. Results The 131I uptake rates by the subjects' thyroid glands at 2, 4, and 24 hours obtained using a double-tube standard source load model were lower than those obtained using a single-tube standard source load model; the differences were statistically significant (P ＜ 0. 05). Radioactive counts obtained using the double-tube standard source load model in different positions were higher than those obtained with the single-tube standard source load model; the differences were statistically significant (P ＜ 0. 05). Radioactive counts decreased with increased displacement when models were placed at 10, 12, 14, 16, and 18 cm in the horizontal direction, and at 0, 1, 2, and 3 cm in the vertical direction. Conclusion The l31I uptake rates by the subjects' thyroid glands observed using a double-tube standard source load model were lower than those observed using a single-tube standard source load model.