Tele-curie-therapy may be defined as the treatment of malignant tumors by gamma rays, from radium at a distance from the skin. Our conception of tele-curie-therapy is the use of large amounts of radium, from 1 to 5 grams, at distances of 5 to 10 cm. or more from the skin. The apparatus used in tele-curie-therapy are referred to as cannons, packs, or bombs. In this paper we shall refer to them as packs.
Generally speaking, we may say that the more deeply situated the malignant process, the greater should be the distance between the radium and the skin. This is an application of a well known law of physics, which states that the greater the radium skin distance (RaSD), the greater the percentage depth dose, as shown in Table I, columns 3, 4, and 5. This table also shows that the intensity reaching the skin is less, the greater this distance. Therefore, in order to attain the required dose, the treatment time must be prolonged, sometimes beyond practical limits. To reduce the time of exposure to a period which may be more easily tolerated, larger quantities of radium must be used.
The use of large quantities of radium necessitates surrounding the radium by heavy lead walls which serve as a protection to the patient and worker, and also confine the beam to the size of the field chosen.