Alpha-particle autoradiography in CR-39: a technique for quantitative assessment of alpha-emitters in biological tissue

Abstract

The techniques for a-particle autoradiography based on the plastic nuclear track detector CR-39, previously reported, have been developed considerably. The techniques are applied to a-autoradiography of human lung tissue in particular but are applicable to any biological tissue.The most important developments are: Ci) Improvements in the manufacture and pre-etching of the plastic. These allow activities as low as Ci g" to be determined. (ii) High resolution a-particle spectroscopy in CR-39 plastic based on the analysis of the structure of the etched track. This enables the energy of individual a-particles to be determined to -35 keV. (iii) Calculation of the effective thickness of tissue sampled by the plastic. This relates the tissue activity to the track density on the plastic. (iv) A deconvolution analysis which takes the distributions of track length and dip angle in the plastic and determines the a-particle range spectrum and distribution of tissue activity with height above the plastic surface. This enables both the absolute abundance and the microdistribution of a-active nuclides present to be determined. (v) The analysis of radon diffusion in tissue to determine the mean padon diffusion distance in tissue and plastic.

Alpha Particles Induce Apoptosis through the Sphingomyelin Pathway

“…With use of the CR39 polymer etching technique described elsewhere (30), we were able to determine the precise rate and uniformity of the α-particle flux. Each etched pit in the polymer represents a single α-particle collision (Fig.…”

Morphological features of the microdistribution of naturally occurring 210Pb/210Po and 226Ra in the teeth of children and juveniles

“…When 226 Ra decays in teeth at the storage temperature of 220 ‡C, the resulting 222 Rn atom diffuses on average only about 100 mm before the a-decay of 222 Rn itself, followed by 218 Po and 214 Po (Fews and Henshaw 1983). Depending on their proximity to the detector surface, one, two or three of these latter decays may be recorded, with the result that characteristic point double or triple a-tracks may be seen.…”