PTH and primary hyperparathyroidism: Background: This study investigates the use of near-infrared fluorescence imaging (NIFI) as an alternative to intraoperative parathyroid hormone (ioPTH) measurement in patients with primary hyperparathyroidism (PHP) due to parathyroid adenoma (PA) with two preoperative imaging examinations in agreement on the position of the altered parathyroid gland.