STUDIES ON THE QUANTITATIVE AUTORADIOGRAPHY .2. RADIOLUMINOGRAPHY FORQUANTITATIVE AUTORADIOGRAPHY OF H-3

The process of obtaining H-3-autoradiographic (ARG) images has been ex pected for a long time. A few X-ray films with no protection layer are commercially available, however, they do not give a reliable image wh ich can be quantitated and can give good contrast. We tried to fabrica te a H-3-type sensor which has no protection layer on a highly sensiti ve sensor, and called it Imaging plate (IP). The IP is composed of one of the specially designed photo-stimulable phosphors containing of Ba FX: Eu2+(X = Cl, Br or I) crystals. Results indicated a good contrast and reliable whole-body ARG image of H-3-labelled glucose with trial I P, which has never been obtained with any X-ray films even if these we re subjected to a long exposure time. The ARG image can be displayed b y either black-and-white hard copy or a colored one with the digital d isplay representing relative intensity of photostimulated luminescence (PSL) without bark ground (BG) or relative intensity concentration (( PSL-BG)/S), where S was equivalent to 100 pixels (1 mm(2)). Similarly to the experimental results of C-14, the linear relationship relative intensity and radioactivity of the H-3 standard sources was demonstrat ed with a very wide range of 10(2) to 10(5) dpm/mg upon the exposure f or 7d. Also the relationship between relative intensity and relative e xposure (radioactivity x exposure time) was linear within the latitude of relative intensity 10(1) to 10(5) (PSL-BG). The trial IP was parti cularly effective for the quantitative autoradiography of TLC plates. After development, a good linearity was demonstrated between PSL inten sity and radioactivity for each spot on the TLC plate, in a wide latit ude of 1 to 10(4), which is similar to that obtained in the C-14 exper iments. These data strongly support the practical use of the TP and BA S2000 for processing a computerized image for quantitative analysis of macro-autoradiographs obtained with not only C-14-labelled drugs but also H-3-labelled drugs.