Estimation of Tc-99m-MAG3 clearance by single-sample methods and camera-based methods

We compared single-sample methods, proposed by Russell et al. and Bubeck ct al., and camera-based methods in calculating Tc-99m-MAG3 clearance, and de termined camera-based methods that provide estimates comparable to those me asured by the Russell method. Twenty-one patients underwent Tc-99m-MAG3 ren al scintigraphy, and clearance was measured by the Russell method and Bubec k method. Various renogram parameters were determined based on the slept: o f the renogram and area under the renogram, and correlated with the clearan ce measured by the Russell method. Camera-based clearance was calculated wi th the obtained regression equations and with equations determined previous ly using the Bubeck method as a standard. The Bubeck method provided lower measures than the Russell method in high renal function. Clearance measured by die Russell method was well correlated with renogram parameters, and cl earance calculated with the obtained regression equation was comparable to that measured by the Russell method. When camera-based clearance was predic ted with the previous equation, it was lower than the result obtained by th e Russell method in high function. In conclusion, there are systematic diff erences in Tc-99m-MAG3 clearance calculated by different methods. The camer a-based methods obtained in this study appear to facilitate: comparison of results obtained by the Russell method and camera-based method.