[Calculation of the dosage distributions in intracavitary radium applicators based on measurements of the directional dependence of the dose rate].

A simple method for the calculation of dose distributions around intracavitary radium applicators has been developed. The cylindrical activity distribution of a single radium source is simulated by a row of point sources. The inverse square law for point sources is modified by two factors, one depending on direction and the other on distance, to account for absorption and scatter in the sources, applicator, and tissue. Factors depending on direction for Buchler applicators (intrauterine tubes, round plates, and cones) have been determined from measurements in a water phantom, because the angular dependence of dose rate in tissue differs from that in air owing to the influence of scatter.