Thyroid nodules cannot be graded by size alone, so a thyroid nodule of 6 millimeters cannot determine what grade it is. Imaging is required, and thyroid nodules are generally categorized into six grades. Thyroid nodules are masses that form in the tissues of the thyroid gland after abnormal hyperplasia. Thyroid nodules are generally categorized into six grades according to the TI-RADS classification. The higher the grade, the higher the risk of thyroid cancer. Thyroid nodules graded at or below grade 3 have a higher probability of being benign nodules, while those graded at grade 4 or above may be malignant, and those graded at grade 6 may be definitively malignant. In addition, most patients with thyroid nodules have no obvious symptoms, and some patients may have symptoms such as pain around the nodule and foreign body sensation. Patients with benign nodules and no obvious symptoms usually do not need treatment and regular checkups are sufficient; patients with malignant nodules diagnosed by pathology can usually undergo surgical resection as prescribed by the doctor. It is recommended that patients go to the hospital if they find thyroid nodules.