High Resolution Neutron-induced Autoradiography of Bone Containing 239Pu

Abstract

The detailed neutron-induced autoradiographic process for bone containing 239Pu produces autoradiographs with both fission fragment tracks and a corresponding bone image. Seven-microns-thick undecalcified bone sections were affixed on 300 micrometers-thick Lexan (polycarbonate) film coated with 0.5 % calf skin gelatin and exposed to neutrons in the thermal column of the Material Testing Reactor (MTR) at the National Reactor Testing Station in Idaho. The specimens were immersed in 28 % KOH at 50°C for 1–12 hours to each pinholes at the location of each fission track and to pit the film at the location of the bone. When the films were etched immediately after irradiation, no bone image was produced, but when the bone sections were allowed to remain on the film for several weeks after irradiation, the irradiated bone caused a pitting of the film surface. Betas from 32P seemed to be the main charged particles available to produce the pitting. This detailed neutron-induced autoradiographic process has advantages over the nuclear emulsion autoradiography of bones because it eliminates long exposure times and fading of latent image. It is a rapid, effective procedure.