Quantitative Intra-operative Assessment of Parathyroid Perfusion Using Indocyanine Green (ICG) Fluorescence Imaging

Inclusion Criteria: * Scheduled for unilateral thyroid lobectomy plus central (VI-level) lymph-node dissection. * Intra-operative findings consistent with: * Complete identification and in-situ preservation of the ipsilateral superior parathyroid gland; * Complete identification and autotransplantation of the ipsilateral inferior parathyroid gland. * Serum 25-hydroxy-vitamin D ≥ 30 ng/mL at baseline; patients below this level may be enrolled after standardized vitamin-D and calcium supplementation with re-test confirming ≥ 30 ng/mL. * Surgery and all postoperative follow-up performed at the study center. * Able and willing to provide written informed consent. Exclusion Criteria: * Prior surgery on the thyroid or parathyroid glands. * Severe hepatic or renal impairment, or other serious metabolic bone disease. * Pregnancy or lactation. * Known hypersensitivity to indocyanine green or iodine-containing compounds. * Inability or unwillingness to comply with postoperative visits and blood testing.