The goal of this open, single-center, prospective, randomized, clinical study is to compare imaging with \[18F\]fluoromethyl-dimethyl-2-hydroxyethylammonium (18F-choline) positron-emission-tomography - computed-tomography, 18F-ch-PETCT, to conventional imaging with ultrasonography and sestamibi scintigraphy in localizing diseased parathyroid glands in patients diagnosed with primary hyperparathyroidism, pHPT. The question this study aims to answer is: can 18-F-ch-PET-CT more precisely localize diseased parathyroid glands in patients with pHPT before surgery? The objective of the study is to help improve precision in parathyroid surgery, thereby increasing cure rates, minimizing complications, and shortening operation times.