Calcitonin Pre-treatment to Improve SPECT-CT Sensitivity

Inclusion Criteria:

• Diagnosis of primary hyperparathyroidism

• Non-localizing SPECT-CT performed within 365 days prior to consent to participate instudy

• Patient desires surgical intervention for treatment of PHPT

• No contraindications to 99mTC-Sestamibi

• No contraindications to treatment with calcitonin

• Serum calcium level prior to non-localizing SPECT-CT is ≥10.5 mg/dL

• Patient consents to participate and undergo second SPECT-CT for purposes of research

Exclusion Criteria:

• Previous surgery to the neck, including resection of parathyroid tissue, exceptwhere end organ damage is present and further surgical intervention is medicallynecessary

• Contraindication to 99mTC-Sestamibi SPECT-CT as evidenced by allergic reaction oradverse event during index SPECT-CT

• Allergy to calcitonin

• Hypocalcemia (contraindication to calcitonin)

• Vitamin D deficiency (contraindication to calcitonin)

• Previous treatment with radioactive iodine

• New prescription of thyroid medication (levothyroxine, armour thyroid tablets, etc.must be taken at time of index scan and research scan)

• Lithium exposure within one year of SPECT-CT (index and research scans)

• Secondary hyperparathyroidism

• Benign familial hypocalciuric hypercalcemia

• Known malignancy, particularly multiple endocrine neoplasia

• New prescription of thiazide diuretic, (thiazide diuretic must have been taken atthe time of index scan and second scan)

• Currently taking calcium channel blockers

• Pregnancy