1. To evaluate the clinical outcomes of ultrasound-guided thermal ablationfor the treatment of benign thyroid nodules;
2. To develop and validate a artificial intelligence model to predict the outcomes of ultrasound-guided thermal ablation in the treatment of benign thyroid nodules

Inclusion Criteria:

• [1]confirmation of benign nodule status on two separate fine- needle aspiration (FNA) or core-needle biopsy (CNB) [2]no suspicious malignant features on ultrasound examination [3]report of cosmetic and/ or symptomatic problems or concern of nodules growing rapidly or malignant transformation [4]refusal or ineligibility for surgery [5]follow-up time ≥6months

Exclusion Criteria:

1. follicular neoplasm or malignancy findings on biopsy
2. nodules with benign result on biopsy had suspicious of malignancy in US, including marked hypoechoic, ill-defined margins, taller-than-wide shape or microcalcifications
3. patients with cystic nodules
4. patients with contra-lateral vocal cord par- alysis
5. previous radiation to the head and neck
6. ; follow- up time less than 6 months