Precision of measurement of tissue concentrations by RLG

Existing investigations about the precision of radioluminography (RLG) are restricted to descriptive analysis of the tissue samples. The aim of the pr esent experiments was to obtain a general prospective statement about the p recision that the RLG; method can achieve. Several pharmaceutical companies in Europe participated in the experiments. Albino rats of various strains were dosed with various C-14-labeled compounds. Whole-body sections were pr oduced, and blood calibration scales were set up with standard radioactivit y sources of dog or rat blood. Photostimulated luminescence was detected us ing Fuji imaging plate BAS-III, For each organ separately, variability was investigated on each of the levels: rat, section of rat, region within sect ion, and residual, with the help of variance components. The producing comp any was seen as a fixed factor and adjusted for. A mixed linear model was f itted to the log-transformed data. The variance component (SD estimate) for the residual term gave the desired prospective statement about the achieva ble precision of the RLG method. Exponential back transformation from the l ogarithmic to the natural scale transformed the SD estimates to multiplicat ion factors. in total, 29 organs were investigated. The RLG method was comp arable in precision to the dissection/combustion method. (C) 2000 Academic Press.