Long hours in a car, the lower limbs can appear swollen, medically known as “traveler’s edema”. Therefore, when riding in a car, you should not always sit, but always change your position, or stand for a while or sit for a while with your lower limbs elevated, or massage your lower limbs from above to below to help blood flow back. Traveler’s edema can be checked by the triiodothyronine inhibition test: After taking exogenous T3 in normal people, the blood T3 concentration increases, which can inhibit TSH secretion in the anterior pituitary gland through negative feedback, and the thyroid uptake rate of 131I is significantly reduced. In patients with diffuse goiter with hyperthyroidism, the presence of long acting thyroid stimulator (LATS) and long acting thyroid stimulator protector in the blood can stimulate the thyroid gland to cause an increased 131I uptake rate without T3 inhibition. There is sometimes an overlap between normal and hyperthyroid values in the 131I uptake function test, which may affect the diagnosis of the disease. The triiodothyronine suppression test is used for the differential diagnosis of patients with high iodine uptake rates. The method is: 60-100mu/g of triiodothyronine sodium is administered orally in 3 doses for 6 days, and the radioisotope iodine uptake test is repeated. The triiodothyronine suppression test method is used for the differential diagnosis of patients with high iodine uptake rates. This test is mainly used for the diagnosis of atypical hyperthyroidism and T3 hyperthyroidism, and as an indicator of the ease of relapse after discontinuation of long-term antithyroid drug therapy.