Neutron autoradiography of tissue slices with boron-10: nuclear track density variation with thickness

Boron microdistribution in tissue sections can be studied by the neutron autoradiography technique in solid state nuclear track detectors (SSNTD), which permits to establish a correlation between the histological images and the location of nuclear tracks on the detector surface. Samples from Boron Neutron Capture Therapy (BNCT) protocols are of special interest. Tissue characteristics as well as the range of the charged particles issued in the ¹⁰B(n,α)⁷Li capture reaction, may determine the minimum slice thickness necessary to obtain reproducible results with this methodology. The evaporation produced in the tissue slice (and its consequent shrinkage) after being mounted on the track detector surface should be taken into account. In this work the variation of nuclear tracks density with thickness of samples from NUDE mice and hamsters included in BNCT protocols was studied. The experimental results were compared with values obtained from a stochastic model of track detection in conditions reproducing the experiment, with the BPSS (Boron Particle Stochastic Simulation) v.1.0 code. It was found good agreement between curves of track density vs. tissue thickness obtained with the stochastic model and those realized with measured values. It was also determined that for 30 μm thickness tissue slices reproducible results are obtained. Results between different samples are also comparable. (author)