Studies on the Quantitative Autoradiography. II. Radioluminography for Quantitative Autoradiography of 3H

The process of obtaining 3H-autoradiographic (ARG) images has been expected for a long time. A few X-ray films with no protection layer are commercially available, however, they do not give a reliable image which can be quantitated and can give good contrast. We tried to fabricate a 3H-type sensor which has no protection layer on a highly sensitive sensor, and called it Imaging plate (IP). The IP is composed of one of the specially designed photo-stimulable phosphors containing of BaFX : Eu2+ (X=Cl, Br or I) crystals. Results indicated a good contrast and reliable whole-body ARG image of 3H-labelled glucose with trial IP, which has never been obtained with any X-ray films even if these were subjected to a long exposure time. The ARG image can be displayed by either black-and-white hard copy or a colored one with the digital display representing relative intensity of photostimulated luminescence (PSL) without back ground (BG) or relative intensity concentration ((PSL-BG)/S), where S was equivalent to 100 pixels (1 mm2). Similarly to the experimental results of 14C, the linear relationship relative intensity and radioactivity of the 3H standard sources was demonstrated with a very wide range of 102 to 105 dpm/mg upon the exposure for 7 d. Also the relationship between relative intensity and relative exposure (radioactivity×exposure time) was linear within the latitude of relative intensity 101 to 105 (PSL-BG). The trial IP was particularly effective for the quantitative autoradiography of TLC plates. After development, a good linearity was demonstrated between PSL intensity and radioactivity for each spot on the TLC plate, in a wide latitude of 1 to 104, which is similar to that obtained in the 14C experiments. These data strongly support the practical use of the IP and BAS2000 for processing a computerized image for quantitative analysis of macroautoradiographs obtained with not only 14C-labelled drugs but also 3H-labelled drugs.