A nodule in the body indicates a growth in the body, and the cause varies depending on where the nodule occurs. If it is a thyroid nodule, it can be hereditary, or it can be related to insufficient or excessive iodine intake. If the nodule has low echogenicity, unclear border, aspect ratio >1, sand-like calcification or abnormal blood flow signal inside, it usually indicates a high possibility of thyroid cancer. If benign or malignant is suspected, a small amount of tissue can also be removed by fine needle aspiration for pathological examination. If the diagnosis is thyroid cancer, radical thyroid cancer surgery is required. If the nodule is considered benign, it can be followed up if the nodule is small, or surgical excision can be performed if the nodule is large and has pressure symptoms or causes hoarseness.