Inclusion Criteria:  subjects who will have thyroid surgery subjects who has no evidence of lymph node metastasis on palpation and imaging (cN0) subjects who has thyroid nodule under 4cm (<cT2) subjects who has no distant metastasis (M0)  Exclusion Criteria:  subjects who has clinical evidence of lymph node metastasis (cN1a or cN1b) subjects who has both thyroid nodule subjects who underwent any radiotherapy on neck subjects who has primary hyperparathyroidism subjects who underwent head and neck surgery subjects who disagree to do this trial