Radioluminography (RLG) in the Drug Evaluation Studies: Validation, Microplate-RLG and a Quantitative Whole Body Autoradiography

Abstract

Radioluminography (RLG) has been developed as one of the two-dimensional radiodetection techniques and widely applied to the drug evaluation studies. As the validation items of RLG, 1) the uniformity examination in fl-ray sensitivity, 2) the evaluation of background PSL value (PSL_BG) and monitoring radioactive contamimination of IP, and 3) the accurate expression of radioactivity in Bq instead of PSL were pointed out. The uniformity in β-ray sensitivity was examined by analyzing the IPs exposed to a planar ¹⁴⁷Pm radiation source. A small but definite non-unifomiry in sensitivity was observed, which could be attributed to the mechanics of BAS. New methods for accurately evaluating PSL_BG and monitoring radioactive contamination of IP were proposed. The usefulness of microplate-RLG as off-line counting of HPLC was emphasized. A new radiographic method that images the density distribution of lyophilized animal sections of WBA was described. This technique made it possible to measure the thickness (mg/cm²) of each tissue and correct the self absorption of β-ray, and thereby opened a road to a genuine quantitative WBA.