99mTc-DTPA volume of distribution, half-life and glomerular filtration rate in normal adults

Background and aim Assessment of volume of distribution (V-D) and half-life (T-1/2) values during glomerular filtration rate (GFR) investigations is a useful quality control check. The aim of this study was to derive reference data for V-D and T-1/2 and also to provide reference data for GFR from studies performed using Tc-99m-diethylenetriaminepentaacetic acid (Tc-99m-DTPA).Methods This was a retrospective study of 126 healthy potential kidney donors (age range 18-59 years). The GFR was evaluated from Tc-99m-DTPA plasma clearance using the 2004 British Nuclear Medicine Society guidelines. The association between V-D and body surface area (BSA) was assessed. T-1/2 was correlated with age and GFR. The correlation between the Brochner-Mortensen-corrected GFR (BM-GFR(Corr)) and age was evaluated.Results The uncorrected V-D value (l) was 10.1xBSA +/- 40.6% (P<0.01). The corrected V-D value (l) was 8.19xBSA +/- 34.4% (P<0.01). In individuals under the age of 40 years, the mean T-1/2 was 95.0 min +/- 36.2%. In individuals aged 40 years and above, the T-1/2 increased at a rate of 0.49 min/year (P=0.04); the T-1/2 (min) was 9480x(1/BM-GFR(Corr))+/- 35.1% (P<0.01). In individuals younger than 40 years of age, the correlation between BM-GFR(Corr) and age was not statistically significant (P=0.45), and the mean GFR was 108 ml/min/1.73 m(2)+/- 27.5%. In individuals aged 40 years and above, the BM-GFR(Corr) was 170-(1.55xage) ml/min/1.73 m(2)+/- 36.7% (P<0.001).Conclusion Well-defined reference data for V-D and T-1/2 can be used for quality control checks in GFR investigations. In addition to these, reference data for GFR using Tc-99m-DTPA have been defined. This will enhance the interpretation of adult Tc-99m-DTPA GFR measurements.