Inclusion Criteria:

- Documented history of a solitary thyroid nodule or a dominant nodule within
multinodular disease, with fine needle aspiration demonstrating a follicular or
indeterminate cytologic examination. If a core needle biopsy was performed instead
of a fine needle aspiration, demonstrating follicular or indeterminate cytology, the
patient is eligible if the biopsy procedure was felt to be minimally disruptive to
the nodule architecture, based on a review by the PI or nuclear medicine
investigator.

- Thyroid nodule must be palpable on physical examination or have a minimum size of 1
cm in diameter by ultrasonography, CT or MRI. The minimum size criterion was
established to address the spatial resolution limitations of PET/CT imaging.

- Scheduled for surgical excision of thyroid nodules within 3 months of the date of the
FDG-PET/CT scan.

- Ability to tolerate lying supine for a FDG-PET/CT examination.

- Age >/= 18 and be limited to adults.)

- Willing to participate in all aspects of the study (patient may opt out of the tissue
collection portion.)

- Patient must be euthyroid with a serum TSH or a free T4 level within the
institutional upper and lower limits of normal, measured within 6 months of
registration. NOTE: mild deviations from the institutional normal limits may be
considered acceptable if the patient has achieved a clinically euthyroid state with
medication at a stable dose for >3 months, and the TSH is considered to be at target
by the patient's treating physician. In patients with hyperthyroidism requiring
treatment, this euthyroid state may be achieved with administration of a thionamide
such as propylthiouracil prior to FDG-PET/CT exam. Patients with hyperthyroid
inflammatory conditions such as thyroiditis and toxic multinodular goiter often
exhibit increased glucose uptake resulting in diffuse uptake of FDG which may obscure
visualization of a thyroid tumor.

- If female, patient must have a negative pregnancy test at the time of registration,
be post-menopausal (with no period in the last twelve months), have had a tubal
ligation at least twelve months ago, or have had a hysterectomy.

- In patients with multinodular disease and a dominant nodule, the nuclear medicine
physician responsible for FDG-PET/CT scan interpretation must determine whether the
indeterminate nodule can be discriminated on FDG-PET/CT imaging prior to enrollment.

- A signed and dated written informed consent obtained from the patient or the
patient's legally acceptable representative prior to study participation.

Exclusion Criteria:

- Patient has a fasting glucose level > 200 mg/dL at the time of the PET/CT scan

- Patient has had prior neck surgery or radiation that in the opinion of the
investigator has disrupted tissue architecture of the thyroid

- Patient has evidence of infection localized to the neck in the 14 days prior to the
FDG-PET/CCT scan

- Patient does not meet any of the inclusion criteria