False-colour scintigram (gamma camera scan) of the human kidneys. The scintigram was obtained following the intravenous injection of the radio- isotope technetium-99m (99mTc) labelled to dimercaptosuccinic acid (DMSA), a compound that is taken up by the renal tubules in the kidneys which is not excreted in urine in any significant quantities. Gamma camera scanning using DMSA provides a comparison of activity in both kidneys that is representative of their state of function & anatomy.