The thyroid gland may have a diffuse or focal uptake of numerous PET/CT radiopharmaceuticals and this may be correlated with underlying benign and malignant thyroid/parathyroid pathologies.

It is not clear at present if the uptake of the radiopharmaceutical alone is associated with a potential malignancy of the disease.

The aim of the study is to collect evidence and consolidate the diagnostic power of PET/CT, to identify any predictive parameters that can determine whether PET positivity/negativity can in the future avoid unnecessary tests such as needle aspiration.

The primary objective of the study is to measure the diagnostic performance of PET/CT (with tracers used in our Center for Nuclear Medicine by normal clinical practice), in the identification of malignancy of thyroid or parathyroid findings, compared to cytological/histological examination in patients with known thyroid and/or parathyroid disease or in patients with incidental findings. The secondary objective is to find functional parameters and predictive imaging of malignancy/benign and risk class of the lesion.

Inclusion Criteria:

For the retrospective part:

• Patients aged >18 years,
• Findings of hypercaptant of thyroid/parathyroid relevance to PET/CT or known thyroid or parathyroid pathology and subsequent execution of PET/CT according to normal clinical practice,
• Patients with cytological examination derived from needle aspiration performed no more than 12 months time apart from PET/CT.
• Obtaining informed consent

For the prospective part:

• Patients aged >18 years,
• Finding hypercaptant findings of thyroid/parathyroid relevance to PET/CT or known thyroid or parathyroid pathology and subsequent execution of PET/CT according to normal clinical practice.
• Patients scheduled for agesult to be no more than 12 months.
• Obtaining informed consent

Exclusion Criteria:

• Nothing

Patients belonging to the U.O. of Nuclear Medicine IRCCS - University Hospital of Bologna - Polyclinic S. Orsola, who have performed or are to perform PET/CT for thyroid/parathyroid disease or other clinical indication with incidental detection of thyroid/parathyroid disease or patients undergoing PET/CT with known thyroid/parathyroid disease (for example, patients with thyroid nodules already subjected to needle aspiration) as part of the normal care path for a period of 5 years and 6 months.