The effect of a delayed chronic DTPA treatment on the Pu microdistribution in rat bone. preliminary results using hemi-blocks of femurs

We have developed a combined autoradiographic and confocal microscope analysis to visualize the decorporation of Pu in bone after delayed and chronic DTPA treatment using hemi-blocks of femurs. 238Pu-citrate was administered to rats by intravenous injection at 21 weeks of age. Treatment by adding Zn-DTPA (1 mM) to the drinking water for one month was performed at 42 and at 85 days after contamination. Bone decorporation was estimated at 10-15% and at 5-7% at the end of the first and the second treatment, respectively. Because the block thickness was larger than the range of α particles in the tissue (25-30 μm), quantitative α track recording can be performed with a spatial resolution of less than 60 μm. The autoradiographs were compared with confocal images of the hemi-femur block surface so that the different bone compartments could be easily identified. With this method a clear preferential decorporation of bone surfaces was visualized compared to controls. (orig.)