Calcitonin Pre-treatment to Improve SPECT-CT Sensitivity

Study Overview
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Brief Summary
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Patients with biochemically confirmed primary hyperparathyroidism and non-localizing SPECT-CT exam within the past year will be included. Subjects will be treated with calcitonin to lower calcium levels immediately prior to reimaging. The goal of this study is to determine whether lowering calcium will improve uptake/retention of sestamibi and improve sensitivity of SPECT-CT to localize parathyroid adenoma.

Official Title
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Improving the Sensitivity of Sestamibi SPECT-CT Parathyroid Scan With Calcitonin Pre-treatment for Primary Hyperparathyroidism

Conditions
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Primary Hyperparathyroidism, Hypercalcemia

Intervention / Treatment
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* Drug: Calcitonin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of primary hyperparathyroidism Non-localizing SPECT-CT performed within 365 days prior to consent to participate in study 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, except where end organ damage is present and further surgical intervention is medically necessary Contraindication to 99mTC-Sestamibi SPECT-CT as evidenced by allergic reaction or adverse 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 at the time of index scan and second scan) Currently taking calcium channel blockers Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Treatment Group<br>All subjects in this arm will be treated with calcitonin 200IU 2x per day for 2 days, then 1x on day of SPECT-CT imaging | Drug: Calcitonin<br>* Treatment with calcitonin to lower high calcium levels prior to reimaging exam<br>* Other names: Miacalcin;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity of SPECT-CT | conversion rate from non-localizing to localizing exam | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Surgical Approach | Rate of minimally-invasive surgery compared to four gland exploration | 6 months | 
| Success Rate | Rate of patients in whom surgical intervention was successful in curing hyperparathyroidism | 6 months from surgery |