A new alpha-particle irradiator with absolute dosimetric determination

A new experimental setup for uniform alpha-particle irradiation of cells in vitro is described. The alpha-particle irradiator is based on a radioactiv e Pb-212/Bi-212 source. In the experimental setup proposed, cells are grown directly on a polylysine-coated track-etch material that forms the base of custom-made cell dishes. Alpha-particle irradiation is done through the ba se of the dish, Immediately prior to irradiation, the cell dish is scanned under a microscope, and images of cells with the corresponding coordinates are saved, After irradiation and after the biological end point under study has been determined, the cell dish is etched to develop alpha-particle tra cks in the dish base. A microscope image series of alpha-particle track ima ges is obtained by accurately revisiting every original (preirradiation) ce ll position in the track-etched dish, The number of alpha-particle traversa ls of each individual cell is scored by mapping images of alpha-particle tr acks onto the images of cells recorded prior to irradiation. The uncertaint y of the alpha-particle hit determination is 0.9 mu m. The procedure descri bed thus presents a method for radiobiological experiments with absolute, r ather than statistical, cell dosimetry, (C) 2000 by Radiation Research Soci ety.