Assess the uptake of rubidium-82 in parathyroid adenomas.

Parathyroid adenomas demonstrate uptake of rubidium-82 chloride and can be detected with PET imaging.

The investigators aim to describe the uptake pattern of rubidium-82 chloride in parathyroid adenomas as well as compare the uptake pattern of rubidium-82 chloride to that of 18F-fluorocholine in patients with parathyroid adenoma.

Inclusion Criteria:

1. Age ≥ 18y
2. Ability to undergo imaging logistics
3. Ability to provide informed consent
4. Biochemical evidence of primary hyperparathyroidism
5. Documented parathyroid adenoma on prior 18F-fluorocholine imaging

Exclusion Criteria:

1. Normocalcemic primary hyperparathyroidism
2. Breastfeeding or pregnancy
3. Claustrophobia or inability to undergo imaging logistics
4. Any other history, condition, therapy, or uncontrolled intercurrent illness, which could in the opinion of the investigator affect compliance with study requirements or which would make the participant unsuitable for this study

20 participants with a diagnosis of primary parathyroid adenoma who have previously undergone 18F-fluorocholine imaging will be recruited.