The goal of this clinical trial is to demonstrate that TIR3A nodules with negative genetic test can be safely and effectively treated by radiofrequency ablation, with nodular shrinkage and improvement of clinical symptoms. Fine needle aspiration cytology is the gold standard test for differential diagnosis of thyroid nodules, but sometimes the result can be indeterminate with a risk of malignancy of 10-30%. In these cases the ablation is not indicated and many patients with benign nodules that may benefit from the procedure are not treated. All the patients enrolled must have a TIR3A cytology and negative genetic test for mutations associated with thyroid carcinoma. Before the ablation blood, evaluation of serum TSH, anti-thyroglobulin antibodies, anti-thyroid peroxidase antibodies and calcitonin levels will be performed.