Dynamic renal scanning using 99mTc-MAG-3 in man.

99mTc-labelled mercapto-acetyltriglycine (MAG-3) has recently been proposed as an ortho-iodohippurate (OIH) substitute for dynamic renal imaging. Experience with MAG-3 is, however, still limited and its biokinetics are not completely known. Moreover, most of the published studies have used HPLC purified MAG-3 which is inpractical for routine clinical work. In this study a commercially available kit of MAG-3 which does not require high performance liquid chromatography (HPLC) is used in 10 normal subjects and 15 patients with renal disease. The results obtained lead to the following conclusions: a. MAG-3 provided in kit form is suitable for renal imaging and semiquantitative analysis in routine clinical settings. b. There are significant differences between renal handling of MAG-3 and OIH, but the dynamic studies obtained with MAG-3 can be interpreted with the same criteria used for OIH studies. c. More information on MAG-3 kinetics is needed before this new radiopharmaceutical can be considered as an OIH substitute for truly quantitative studies such as effective renal plasma flow determinations.