With a prevalence of 4-7% of thyroid nodules in the normal population and a detection rate of up to 30-60% in autopsies [7], and approximately 5% of thyroid nodules in the normal population being thyroid cancer [8], the main thing to identify in non-toxic nodular goiter, especially in isolated nodular goiters, is thyroid cancer. 2009 ATA 3rd edition of “Thyroid Nodules and Thyroid Cancer. Clinical Guidelines for the Management of Thyroid Nodules and Thyroid Cancer” states that the risk of thyroid cancer is the same for any one patient with a single nodule and multiple nodules. If there are more than 2 nodules larger than 1 cm, fine needle aspiration cytology should be performed on nodules suspected under ultrasound. The diameter of thyroid nodules that can be palpated on general examination is more than 1cm, and the deeper the location, the worse the effect of palpation; with the continuous development of auxiliary examinations, especially the progress of ultrasound technology, nodules with a minimum diameter of 1-2mm can now be accurately detected again, making the number of patients with thyroid nodules in clinical practice significantly increased. In general, single nodules within 1cm do not require immediate treatment, but can be followed up regularly (3 months later with a review of thyroid ultrasound) to determine changes in the nodules; in addition, some believe that a small amount of thyroid hormone (eugenol 12.5-25μgqd) can inhibit the growth of nodules by reducing TSH, and the nodules can be reviewed after 2-3 months, but in most cases, the efficacy of this treatment is not ideal. efficacy of this treatment is not very satisfactory. For nodules over 1 cm, if they are cystic nodules, they can be treated by puncture to extract the cystic fluid, or inject 32P after extracting the cystic fluid to destroy the cystic wall to avoid recurrence, or be treated by direct surgical excision; for solid nodules, 99mTc-MIBI pro-tumor imaging can be performed first to determine the proliferation of nodules, and if they are positive, surgery is recommended as soon as possible. For goiter caused by non-toxic isolated nodularity, 131I treatment is less frequently used. Generally, 131I treatment is only attempted in patients who are contraindicated to surgery and cannot be operated or are unwilling to operate, but the efficacy is not very certain. In general, only nodules >1 cm in diameter need to be evaluated because these nodules have a high potential for malignancy. Sometimes nodules <1 cm in diameter should also be evaluated when ultrasound findings are suspicious or accompanied by lymphadenopathy, a history of head and neck radiation exposure, or a family history of thyroid cancer (one or more first-degree relatives with thyroid cancer). Various ultrasound features of thyroid nodules often suggest the possibility of malignancy, such as ultrasound showing hypoechoic nodules compared to normal thyroid tissue, abundant blood supply in the nodules, irregular marginal invasion, nodules with microcalcifications, absent haloes, or nodules that are taller than they are wide. Ultrasound suggests the presence of suspicious cervical lymph node infiltrative lesions, which are often specific for malignant nodes, but the sensitivity of ultrasonography is low, otherwise one or more changes in ultrasound imaging are not sufficient to prove the presence of all malignant nodes either in terms of sensitivity or specificity. However, certain imaging changes have a high value in predicting malignant changes. Again, the most common ultrasound changes in papillary and follicular thyroid carcinomas differ between the two. Papillary thyroid carcinoma is usually solid or mostly solid with hypoechoic changes, often with irregular marginal infiltration and a rich blood supply within the nodule. Microcalcifications are more specific for papillary carcinoma but are not easily distinguished from gliosis. In contrast, follicular carcinoma is more likely to have isoechoic or hyperechoic changes with a thick irregular halo, but without microcalcifications. Follicular carcinoma <2 cm in diameter is not associated with distant metastasis.