[Quantitation of absolute and relative renal uptake using 99mTc-DMSA: sequential change in time and correlation with...

A renal uptake of 99mTc-DMSA as a function of time and correlation between 99mTc-DMSA and 99mTc-DTPA in renal uptake were discussed. The absolute renal uptake of 99mTc-DMSA calculated by complete correction of tissue attenuation and physical decay showed increase by 5 hours after the administration, except one case with congestive heart failure. The net renal counts attained a maximum between 2 to 3 hours after the administration. There was a good correlation (r -0.992, p less than 0.001) between the relative renal uptake of 99mTc-DMSA (2 hour) and that of 99mTc-DTPA (2-3 min). On the contrary, the absolute renal uptake of 99mTc-DMSA as a indicator of total renal function showed a poor correlation (r = 0.419) to GFR calculated from 99mTc-DTPA. The results indicate that the relative renal uptake of 99mTc-DMSA is a reliable quantitative parameter for split renal function. However, the absolute renal uptake of 99mTc-DMSA may be suggested to be a different renal functioning indicator from GFR calculated from 99mTc-DTPA.