The purpose of the study is to investigate the contribution of PET-CT with F18-choline in the diagnosis of thyroid nodule with indeterminate cytology in order to guide the best indication of surgical resection.

Inclusion Criteria:

• Age ≥ 18 years
• Patient with thyroid nodule ≥15 mm with an indeterminate cytology according to the Bethesda Classification 2008 (vesicular lesion of undetermined significance (Bethesda 3); follicular neoplasm or Hürthle cells (Bethesda 4); lesion suspicious for malignancy (Bethesda 5)), and to be operated on
• Patient affiliated to a social security scheme
• Informed consent and signed

Exclusion Criteria:

• Thyroid nodules <15 mm
• Coalescing nodules preventing proper individualization of targeted nodule;
• Thyroid nodule with non-diagnostic cytology (Bethesda 1), benign cytology (Bethesda 2) or malignant cytology (Bethesda 6)
• Hot thyroid nodule on the thyroid scan
• Major subject to a measure of legal protection or unable to consent
• Pregnant women / nursing
• Refusal to participate