Radioluminography for quantitative autoradiography of 14C.

The aim of this study was to elucidate whether or not quantitative analysis of autoradiographs could be obtained with a [14C]-labelled compound by the use of new type radiosensor, so called 'imaging plate' (IP). Since X-ray films were first used as a radiosensor for macroautoradiography by Ullberg (1), many kinds of X-ray films have been used but the other sensors have never been used. Our results indicated that there was an excellent relation between relative intensity (PSL-BG) and radioactivity on a given area which was completely linear. The linearity was observed in a relatively wide range between 10(1)-10(5) dpm orders of radioactivity. About 100 times greater sensitivity of the IP than any X-ray film was demonstrated by the use of not only [14C]-radioactive standard sources but also by experimentally provided [14C)-radioactive spots developed on a TLC plate and macroautoradiographs (MARG). In order to obtain reliable quantitative data from a MARG image, it was required that a thin specimen section be kept at a constant level of thickness under freezing condition through out the exposure time. Results also showed that the linear relation of relative intensity versus radioactivity of the specimens had a very wide range from 10(1)-10(5) dpm/mg of exposure within 7 days. Furthermore, the relation of relative intensity versus relative exposure (radioactivity x exposure time) was linear within the latitude of relative intensity form 10(1)-10(5) (PSL-BG). Finally, a combination of the IP and BAS2000, computerized image display system, was well equipped to completely erase a background memory before use.