Quantitative distribution studies in animals: cross-validation of radioluminography versus liquid-scintillation measurement.
The results of a cross-validation of the radioluminography (RLG) and liquid scintillation counting (LSC) methods are presented. The methods for the determination of radioactivity concentrations were compared in 16 organs, after administration of (14)C-labeled substances to rats. LSC measurements of two kinds were used as reference methods for RLG: (1) quantitative determination of radioactivity after conventional dissection (interindividual comparison) and (2) quantitative determination of radioactivity in tissue punches taken from the whole-body sections after they had undergone RLG measurement (intraindividual comparison). Blood standards containing known concentrations were used for calibration. For statistical evaluation log-linear regression analysis of paired concentration values and organ-specific 95% confidence intervals of the log-transformed RLG/LSC concentration quotients were compared. For most organs, the slopes of the regression lines and the means of the concentration quotients were within the defined equivalence range of 0.80-1.25. Deviations were distinctly smaller in the intraindividual comparison. For some organs, however, it became clear that found concentrations were affected by self-absorption (RLG) and by differences in sample preparation (LSC). In conclusion, quantification with RLG is a reliable and reproducible method with comparable measurement precision and greater accuracy in respect of tissue localization, compared to LSC (dissection).
Steinke
W
W
Preclinical Pharmacokinetics, Bayer AG, D-42096 Wuppertal, Germany. wolfram.steinke.ws@bayer-ag.de
Archimbaud
Y
Y
Becka
M
M
Binder
R
R
Busch
U
U
Dupont
P
P
Maas
J
J
D000818:Animals; D001345:Autoradiography / Q000592:standards; D005260:Female; D008297:Male; D011874:Radiometry / Q000592:standards*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D015203:Reproducibility of Results; D012588:Scintillation Counting / Q000592:standards*; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
D019275:Radiopharmaceuticals