Images of a 71-year-old woman with primary hyperparathyroidism (PHT - 129 pg/ml, Ca - 2.75 mmol/l). Dual-tracer subtraction of both 99mTc-pertechnetate and 99mTc-MIBI planar images did not show a clear focus suspect for adenoma. The subsequent SPET/CT images showed a small lesion located caudally from the right thyroid gland, suspicious for parathyroid adenoma of the lower right parathyroid gland (white arrow on the axial and sagittal views and red arrow on the coronal slices).