Quantification of renal haemodynamics with radionuclides.

Non-invasive quantification of renal function with radionuclides is an important role of nuclear medicine. With modern commercial preparations of technetium-99m diethylene triamine penta-acetic acid (DTPA), glomerular filtration rate (GFR) can be measured accurately either from the rate of disappearance of the tracer from plasma or from its rate of uptake into the kidneys. Determination of the latter with the gamma camera allows measurement of individual kidney GFR. Renal blood flow (RBF) can be measured from plasma clearance of hippurate or from first-pass kinetics of intravenously injected tracer using the gamma camera. The filtration fraction can be obtained from separate measurement of GFR and RBF, either globally from plasma clearance studies or of each kidney from gamma camera studies. Because they are central to the understanding of plasma clearance studies, the effective distribution volumes of the various tracers used for renal function studies are also discussed in detail.