['To probe into an new methods preserving parathyroid gland of patients with thyroid carcinoma.', 'Thirty-six patients with thyroid carcinoma that primary treated were random divided into two groups: trial group and control group. Emulsion of activated-carbon particles was injected into the thyroid gland of trial group patients. After thirty minutes, central compartment dissection was performed in the all patients. The black stained tissue in the dissection specimen of trial group was separated. Total lymph node, metastasis lymph node and parathyroid gland in the black stained tissue, and non-black stained tissue in the central compartment dissection specimen of trial group and central compartment dissection specimen of control group were counted respectively.', 'Nineteen and twenty central compartment dissection was performed in trial group and control group respectively. There are 177 lymph nodes included 83 metastasis lymph nodes in the black-stained tissue of central compartment dissection specimen of trial group. No parathyroid gland was found in the black-stained tissue. Nine lymph nodes included 2 metastasis lymph nodes and 7 parathyroid glands were found in the non-black stained tissue of central compartment dissection specimen of trial group. There were 124 lymph nodes included 80 metastasis lymph nodes and 8 parathyroid glands in central compartment dissection specimen of control group. There are statistic difference between the amount of lymph node in black stain tissue and that of control group (t = 0.340, P = 0.003). Rate of staining lymph node were 95.2 percent.'] Are [ Parathyroid glands differentiated from lymph node by activated-carbon particles ]?