Renal Potassium Excretion Visualized on Rubidium PET/CT.

The positron emission tomography (PET) flow tracer Rubidium 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 Rubidium 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 Rubidium PET/CT.