Microbeam and Partial Cell Irradiation

Abstract

Publisher Summary This chapter discusses the techniques for carrying out microbeam or partial cell irradiations, and also describes the biochemical effects of partial cell irradiation. In the ultraviolet field both Bessis and Nomarski and Czihak described pieces of apparatus for producing very finely focused beam down to 1 μ in diameter. Among the new pieces of apparatus for producing ionizing microbeams Pohlit has described an electron canon for producing a bundle of electrons down to 1 IL in diameter using a magnetic lens to focus the beam. Also among the heavy particle ionizing microbeams Morgan et al. have described a novel apparatus for producing a high-energy proton microbeam. One of the most recent and interesting developments is the optical microbeam described by Bessis et al. who used a ruby “LASER” (Light Amplification by Stimulated Emission of Radiation) as a source and a microscope in reverse to reduce the diameter of the extremely intense light beam. The chapter also discusses the morphological effects produced by partial cell irradiation such as: paling, pindle disappearance, phragmoplast disappearance, and other chromosomal effects. In partial cell irradiation experiments using ultraviolet, effects on nuclear processes following irradiation of the cytoplasm are observed. In some cases irradiation of the same area with an ionizing beam of radiation does not produce the same effect and there appears to be a quite fundamental difference between the action of ultraviolet and, for example, a microbeam of protons.