**6.3 Strengths and limitations**

99Tc-DTPA presents the advantages and inconvenient of other isotopic methods (see 51Cr-EDTA paragraph). The dosage of the marker is relatively cheap and precise. His short halftime makes it a few less practicable than 51Cr-EDTA. Among the most important advantages of 99Tc-DTPA, we underline the fact that it is the only marker that can be coupled with nephrogram to give separated function between the two kidneys (Durand et al., 2006). Physiological data to confirm its role as a reference marker are however clearly lacking. We also think that global performance of 99Tc-DTPA compared to inulin is probably a few less than the 51Cr-EDTA, especially with plasma clearances (at least in part because 99Tc-DTPA is binding to proteins).
