Techniques for studying the distribution of alpha -emitting and fissionable radionuclides in histological lung sections

Abstract

Describes how the distribution of alpha -emitting and fissionable radionuclides, in this case a mixture of uranium isotopes, in histological sections of lung can be measured using either the NIAR technique or alpha -autoradiography with cellulose nitrate films. Since both techniques allow the section to be preserved it was possible to use the same section for NIAR, for alpha -autoradiography and for delayed-neutron analysis. The delayed-neutron analysis made it possible to assay the total amount of uranium present in each section and thus to determine the absolute detection efficiencies of the NIAR and alpha autoradiographic techniques. The NIARS and alpha -autoradiographs allowed the authors to measure not only the total amount of uranium present in each section, but also its microscopic distribution.

Influence of macrophages on microdistribution of inhaled UO2aerosol in rat lung

“…There were usually eight slices from the LL and three from the RAL depending on the size of the lungs. The slices were processed and embedded in low viscosity epoxy resin by the methoa of Spurr (1969) and sections of nominal thickness 2.5, 5 and 10 pm cut from the embedded slices for neutron induced autoradiography, NIAR (Jenner and Thorne 1980). Using other similar rats that had inhaled the U 0 2 aerosol and for which the lungs had been fixed in the same way as described (section 2.2), it was shown that the processing of the lung slices through the various liquids up to the point of embedding in the resin did not significantly remove any U 0 2 from the tissue.…”

“…Measurement of Na. NA was measured in the cut sections by the NIAR method (Jenner and Thorne 1980). When exposed to slow neutrons the foci emitted fission…”

“…When there was no increase in the mean number of clusters recorded per unit area with increased neutron fluence it was assumed that all the U 0 2 foci had been revealed. A Quantimet 720 system 30 image analyser was used to count the number of clusters in each field (Jenner and Thorne 1980).…”

“…The variance of NAr is since k is the same for each section. The thickness of each section was measured (Jenner and Thorne 1980) and for each nominal thickness a mean value and its standard error was derived for the n sections from each LL or RAL. The standard errors were based on a pooled sample variance, since checks (using Bartlett's test) revealed no serious differences between the variances of the thickness measurements at the different nominal thicknesses.…”

Alpha and fission fragment autoradiography with superimposed tissue images in CR-39 plastic

“…recently by detecting the a-emissions from U in cellulose nitrate (Jenner and Thorne 1980). This detector is sensitive to a wider range of charged particles than Lexan.…”