Radio-active Substances and Their Therapeutic Uses and Applications

Abstract

The Employment of Buried Radium Emanation THOUGH dosage and the proper distribution of the sources of radiation are important in any method of employing this therapy, in none are they of so great moment as when the method of buried emanation is under consideration. It is at once apparent that ideal conditions cannot obtain in all cases, or, to be exact, in any case, for the particular tissue or tumor which is to be treated will invariably present individual characteristics and peculiarities which cannot be absolutely subordinated to any fixed rules. All living things are subject to individual variations, and in the application of radium, an active substance, to human tissue, a living organism, we are confronted with a twofold problem. We have already (in a previously published paper of this series) explained the method of preparing radium emanation tubes or “seeds.” The problem confronting the clinician is the number of these tubes which he shall employ in a given case, and the several locations within the area of tissue to be irradiated where these tubes can be disposed to the greatest advantage. Where the greatest attention has been given to this particular form of radium therapy it has been found that complete retrogression of a tumor growth can be accomplished in the great majority of cases by a single treatment, and that such a result—if it can be accomplished—assures greater likelihood of halting the disease process at an early stage, as it gives no opportunity for further extension having its rise in remnants of diseased tissue, the destruction of which was not completely accomplished. Thus the selection of dosage and location for the initial treatment becomes a matter of paramount importance. The object to be attained is to destroy the neoplasm or pathologic area completely, but at the same time to reduce the caustic action to the lowest possible minimum, while avoiding the production of extensive necrosis. Necrosis Due to Embedded “Seeds” It would be desirable, but is—because of the limitations of our present knowledge—unfortunately impossible, to eliminate all necrosis about the tubes used in deep implantations of radium emanation. At the Memorial Hospital, for example, no tube is used which contains more than 3. millicuries or less than 0.1, and it has been observed clinically, and substantiated by careful experimentation upon animals, that any of these tubes imbedded for periods varying within two months, will unfailingly produce an area of necrosis one centimeter in diameter,—this necrosis being due to the intense beta and soft gamma radiation which takes place in the immediate vicinity of the tube.