What is the difference between the two imaging agents, Tc-99m MAG3 and Tc-99m DTPA?

Tc-99m MAG3 is cleared predominantly via tubular secretion (80%), with a small amount of clearance occurring by glomerular filtration (20%). It is concentrated more effectively by the kidneys than is Tc-99m DTPA, particularly where there is poor renal function.

Tc-99m DTPA is cleared via glomerular filtration. It is a relatively inexpensive agent that is used for patients with native kidneys and normal renal function.