Simple methodology for ensuring the precision of measuring radioactivity at low concentrations in very small tissues using quantitative whole-body autoradiography.

Simple methodology for ensuring the precision of measuring radioactivity at low concentrations in very small tissues using quantitative whole-body autoradiography. Regul Toxicol Pharmacol. 2020 Nov 20;:104835 Authors: Hironaka T, Inazawa K, Tanaka Y, Hasegawa H Abstract Quantitative whole-body autoradiography (QWBA) is largely used to evaluate tissue distribution of small molecule drugs. In QWBA, radioactivity is measured as the intensity obtained from the autoradiogram. It is known that lower intensity per a region of interest (ROI) or smaller size of ROI increases the variability of intensity. In fact, as some tissues are very small (e.g., choroidea), ensuring reliability on the intensity for measuring radioactivity in these tissues is difficult in case of under- or over-estimation of radioactivity concentration owing to their variation of low radioactivity intensity of ROI. We thus analyzed the relationships between the size, intensity, and precision of ROI to determine the statistically significant lower limit of quantification (LLOQ) in very small tissues. To investigate the difference in correlation between the radiation source (commercial planar radiation standard [com-ST] and self-made radiation standard [self-ST] consisting of radioactive compounds and matrices), apparatus, or setting environment of the apparatus, correlation analysis was conducted under various conditions. Our results revealed that LLOQ can be calculated by...
Source: Regulatory Toxicology and Pharmacology : RTP - Category: Toxicology Authors: Tags: Regul Toxicol Pharmacol Source Type: research