Sensitivity of radioluminography using C-14-labeled tracers in whole-body sections of rats

Radioluminography using photostimulated luminescence recently became popula r for the quantitation of radioactivity in whole-body sections. In order to estimate the limits of the method, the sensitivity was investigated using routinously prepared blood standards with known amounts of radioactivity. T he blood standards underwent the typical steps similar to conventional whol e-body autoradiography including freezing, sectioning, and lyophilizing. Th e limit of detection, defined as 3 times the standard deviation of backgrou nd values, decreases with exposure time from 18 Bq/g wet tissue for 1 day o f exposure to 6 Bq/g for 7 days of exposure. The respective limit of quanti tation defined as 10 times the standard deviation of background is 60 to 20 Bq/g. A similar sensitivity is found when the quantitation limit is define d as reproducible measurement with coefficients of variance below 20%: 60 B q/g can be quantified if the measure area is above 3.5 mm(2). (C) 2000 Acad emic Press.