SPECT/CT with the radiotracer 99mTc sestamibi has become the standard method for pinpointing the tumor. This, however, is a challenge because the parathyroid glands usually are located close to the thyroid and the radiotracer 99mTc sestamibi concentrates both in thyroid and parathyroid tissue. Hence there is a need for a tracer/imaging tool that concentrates in the parathyroid but not in the thyroid.