18F-choline PET/CT for parathyroid scintigraphy
18F-choline PET/CT is a relatively new imaging technique used to localise hyperfunctioning parathyroid tissue and adenomas. The technique is gradually being adopted worldwide, and in our experience, its utilisation has increased in Norway (2). Initially, the technique was only used in cases where precise localisation was difficult with conventional imaging. The method has given excellent results, leading to the gradual phasing out of conventional nuclear medicine methods (3).
Advantages of 18F-choline PET/CT include lower radiation exposure to patients, reduced uptake time, total duration reduced to around half an hour, higher diagnostic precision due to higher resolution, and more time for other investigations (4). Conventional imaging takes around four hours. Additionally, the quality of diagnostic CT scans from PET/CT scintigraphy is superior to that of the SPECT/CT cameras, giving better image quality in an area with many small anatomical structures (3). Diagnostic CT can be used in three phases, i.e. unenhanced phase, arterial phase and portal venous phase, which is highly valued by our endocrine surgeons. However, it is entirely possible to use only unenhanced phase, either with a standard dose or low dose for anatomical localisation in selected cases. In our experience, the radiation doses in PET differ from those in conventional imaging: the radiation dose in PET is a third of that in conventional imaging, with 3 mSv and 10 mSv, respectively.