Renal Potassium Excretion Visualized on 82Rubidium PET/CT

: The positron emission tomography (PET) flow tracer 82Rubidium is a known potassium analogue. During our studies of tumor blood flow in prostate cancer, we found that approximately 10% of the patients had high urinary 82Rubidium activity. In roughly half of these patients, the increased renal rubidium/potassium excretion was either causing hypokalemia or explained by Thiazide treatment. In the other half, there was no obvious explanation or clinical consequence of the renal rubidium/potassium excretion. This is the first time enhanced renal potassium excretion is visualized on 82Rubidium PET/CT.