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

Radioluminography using photostimulated luminescence recently became popular 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. The blood standards underwent the typical steps similar to conventional whole-body autoradiography including freezing, sectioning, and lyophilizing. The limit of detection, defined as 3 times the standard deviation of background values, decreases with exposure time from 18 Bq/g wet tissue for 1 day of exposure to 6 Bq/g for 7 days of exposure. The respective limit of quantitation 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 defined as reproducible measurement with coefficients of variance below 20%: 60 Bq/g can be quantified if the measure area is above 3.5 mm(2).