title: (99m)Tc-DTPA volume of distribution, half-life and glomerular filtration rate in normal adults.
abstract: OBJECTIVE
  Assessment of volume of distribution (VD) and half-life (T1/2) values during glomerular filtration rate (GFR) investigations is a useful quality control check. The aim of this study was to derive reference data for VD and T1/2 and also to provide reference data for GFR from studies performed using Tc-diethylenetriaminepentaacetic acid (Tc-DTPA).
  
  
  METHODS
  This was a retrospective study of 126 healthy potential kidney donors (age range 18-59 years). The GFR was evaluated from Tc-DTPA plasma clearance using the 2004 British Nuclear Medicine Society guidelines. The association between VD and body surface area (BSA) was assessed. T1/2 was correlated with age and GFR. The correlation between the Brochner-Mortensen-corrected GFR (BM-GFRCorr) and age was evaluated.
  
  
  RESULTS
  The uncorrected VD value (l) was 10.1×BSA±40.6% (P<0.01). The corrected VD value (l) was 8.19×BSA±34.4% (P<0.01). In individuals under the age of 40 years, the mean T1/2 was 95.0 min±36.2%. In individuals aged 40 years and above, the T1/2 increased at a rate of 0.49 min/year (P=0.04); the T1/2 (min) was 9480×(1/BM-GFRCorr)±35.1% (P<0.01). In individuals younger than 40 years of age, the correlation between BM-GFRCorr and age was not statistically significant (P=0.45), and the mean GFR was 108 ml/min/1.73 m±27.5%. In individuals aged 40 years and above, the BM-GFRCorr was 170-(1.55×age) ml/min/1.73 m±36.7% (P<0.001).
  
  
  CONCLUSIONS
  Well-defined reference data for VD and T1/2 can be used for quality control checks in GFR investigations. In addition to these, reference data for GFR using Tc-DTPA have been defined. This will enhance the interpretation of adult Tc-DTPA GFR measurements.
authors.affiliation: Department of Nuclear Medicine, Tygerberg Hospital, Stellenbosch University, Cape Town, South Africa. jen@sun.ac.za
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Holness
authors.forename: John S
authors.initials: JS
authors.lastname: Fleming
authors.forename: Alessandra L
authors.initials: AL
authors.lastname: Malaroda
authors.forename: James M
authors.initials: JM
authors.lastname: Warwick
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005919:Glomerular Filtration Rate; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012189:Retrospective Studies; D016284:Technetium Tc 99m Pentetate / Q000097:blood*; D055815:Young Adult
chemical_list: D016284:Technetium Tc 99m Pentetate