“Radium and some methods for its therapeutic application,” with demonstrations

Abstract

Mr. Lieber gave an account of the discovery of radium by Mme. and Professor Curie, and demonstrated many radioactive phenomena. Special attention was drawn to recently discovered facts bearing on radium emanation. For a time it was thought that radium discharged directly (a) the so-called “emanations,” which had practically no penetrating power and which, like a gas, were readily carried from one point to another by an air current; and (b) the so-called “rays”—alpha rays of very low penetrating power, beta rays of considerably greater penetrating power, and gamma rays of enormous penetrating power. Later investigations have shown, however, that radium discharges primarily emanations and alpha rays only. However, the emanations soon disintegrate, and the disintegration products yield the beta rays and the gamma rays. Consequently the powerful beta and gamma rays are the products of a decomposition product of radium. The proportions of the radiations given off by a certain quantity of radium and its disintegrated emanations are about 95% alpha rays and about 5% combined beta and gamma rays. Because of their nearly negative penetrative power, the alpha rays, as well as the emanations, are practically unavailable for therapeutic purposes when the radium is used in glass tubes or similar containers. Even the superficial layers of a given radium preparation are relatively impervious to both the emanations and the alpha rays proceeding from the underlying portions of the preparation. Therefore, it is essential, in order to obtain full radioactive effects, that (1) the given quantity of radium should be spread so thin that, from the practical standpoint, an upper layer would not exist and (2) should be held in a container with walls that would be permeable both by the alpha rays and by the emanations.