PURPOSE: This study explores the impact of microwave ablation on thyroid function in patients with Small Papillary Thyroid Carcinomas, using a specific energy/volume model to optimize treatment and evaluate clinical efficacy. METHODS: A cohort of 70 patients with confirmed Small Papillary Thyroid Carcinomas underwent microwave ablation tailored to individual nodule characteristics. Pre- and post-ablation assessments included ultrasound imaging for nodule size, and thyroid function tests (TSH, Free T4, and Free T3 levels) were conducted at baseline, 1, 3, 6, and 12 months post-treatment. The main results are the complete ablation rate of nodules and the stability of thyroid function after treatment. Secondary outcomes include the incidence of complications and other clinical parameters. RESULTS: The complete ablation rate was achieved in 95% of the nodules, with most patients (90%) requiring a single ablation session. Nodule size reduced significantly from an average of 174.0 ± 259.1 mm3 to 3.2 ±11.3 mm3 , with the mean volume reduction rate (VR) of 98.47 (5.82%) at 18-months follow-up. Stable thyroid function and minimal fluctuations in hormone levels were observed in 90% of patients, demonstrating the effectiveness of microwave ablation in preserving thyroid function. Notably, lower energy/volume ratios were linked to reduced risk of complications and preservation of thyroid function. Only 5% of patients reported minor complications, with no major adverse events. CONCLUSIONS: The study's results validate the clinical utility of Microwave ablation (MWA) in energy/volume setting as an effective, minimally invasive treatment for small papillary thyroid carcinomas.