Study on the practical use of quantitative whole-body auto-radioluminography

The practical use of quantitative radioluminography (RLG) using reading system BAS 2000 (Fuji Photo Film Ltd., Tokyo, Japan) and STORM 820 (Molecular Dynamics, USA) was examined using a chemical matrix as an internal standard, which offers the benefits of being preservative, inexpensive, and easy to handle. The results were as follows: 1. As the water content is within the range of 65-80% for most organs and tissues, we selected a chemical matrix, Tissue-TEK containing 85% water, as a base for the preparation of a standard curve. 2. The calibration curve prepared using Tissue-Tek as the internal standard was compared with the calibration curve using liver paste preparations as the internal standard. The results showed good linearity in both cases, with almost no difference in the slopes of the two calibration curves. 3. The PSL-BG or MD counts/pixel-BG values of the lowest radioactivity concentration measured for small areas of the region of interest (ROI) showed large fluctuations with both BAS 2000 and STORM 820, but the fluctuation became less than 15% at above 25 mm(2) of ROI. 4. The value of dpm/g calculated using the calibration curve prepared from Tissue-Tex internal standards showed a very good correlation with the values of dpm/g obtained by scraping off the tissue from the remaining block and conducting measurements with a liquid scintillation counter.