Comparative Notes on Radon Implants

Abstract

THE present trend of radium therapy shows a divergence into two widely separated lines of endeavor. The first is the skillfully prepared and ingeniously contained radium implants, making possible the accurate introduction of a definite amount of radium emanation or radon into or in contact with an active neoplastic area. The second is the collection of radium salts in quantities large enough to permit of long range radiation similar to but productive of more gamma radiation than that of the present high voltage X-ray generator. The purpose of this paper is to consider some of the problems which confront the radiologist in his routine work, as well as the conditions which call forth the first-named type, the radium “seed,” or implant. The primary requirement is that one should be cognizant of the fact that he is in control of a very small but exceedingly potent agent which necessitates not only a comprehensive knowledge of radiology but also that skill which a well-balanced medical man must possess in all branches which enter into the successful diagnosis and treatment of neoplastic disease. This statement appears superfluous, but when one realizes that these potent radium seeds can be purchased by anyone, and that they not infrequently fall into the hands of those not qualified either by experience or training to use them, the need for caution is apparent. In this manner an agent which is extremely valuable to the trained radiologist may occasion much abuse and adverse criticism, if permitted to run amuck without proper supervision. Glass radon implants have been used for several years with remarkable success in many cases, and with disastrous results in others. Since the advent of platinum and gold filtered points, it is doubtful if the demand for glass tubes will continue much longer. The writers have entirely discontinued the use of glass implants, although in the past many good results have been obtained from the use of them in their clinic. This is especially true in tongue malignancy, where the blood supply is good and the tissue repair of the necrotic primary beta radiation effects more prompt and certain. Probably the great advantage of the filtered implant is due to the fact that a sufficient amount of radium is used to radiate thoroughly the periphery of the lesion, and at the same time serious local necrosis is avoided by the metallic nitration. Correct estimation of the size of the growth is undoubtedly the most important factor in the consideration of the use of radon implants. The work of Quick, Failla, Quimby, Cutler and others, at the Memorial Hospital, has practically solved the dosage problem. Reference to their charts and hypothetical models will guide the operator so that he may remain well within the safety zone of dosage. The previous or older method of using one millicurie per cubic centimeter of malignant tissue, and spacing the tubes one centimeter apart, often caused either overdosage or underdosage.