Hazards of Radiation

Based upon a Dissertation given before the Society on Friday, 11th October 1957.Radiations are of two types: Particulate and Electromagnetic. Particulate radiations are comprised of the sub-atomic particles, electrons, protons, neutrons and alpha particles which, when moving at high speed, possess the property of passing through matter, the depth of penetration being proportional to their kinetic energy and their electrical charge.Alpha Rays which are rapidly moving nuclei of Helium atoms have mass 4 and charge 2 on the atomic scale and have little power of penetration in tissue, reaching to a depth of about 0.05 mm.Beta Rays which are beams of fast moving electrons, can penetrate tissue up to a depth of 2 to 5 mm., and Protons with unit mass and electrical charge lie somewhere between these two.Derived from an external source, these radiations are of little danger since they are obviously incapable of penetrating to the gonads and bone marrow, tissues in which the more sinister biological effects are manifest.These radiations are particularly dangerous when derived from a source which may be ingested with food and perhaps selectively concentrated in body tissues, as, for example, Strontium 90 in bone