While many radium applicators are available for the treatment of cervical cancer, the results obtained by a technic employed at Yale-New Haven Medical Center over the past ten years have proved sufficiently satisfactory to permit its description. Most intracavitary radium applicators used in the pelvis, consisting of an intrauterine tandem and some sort of vaginal applicator, are essentially modifications of two methods, the Paris-Manchester and the Stockholm. The intrauterine radium applicators are roughly similar in the two methods. The vaginal applicators differ in that the Paris corks, Manchester ovoids, or other colpostats based on these are bulkier than the Stockholm vaginal boxes, which are flat and are applied against the surface of the cervix. The Manchester technic was originally designed under the premise that certain injuries to the rectum were due to the high dose received at a point 2 cm from the vaginal fornix and 2 cm lateral to the cervical canal (Point A) as the result of occlusion of the blood supply (10, 11). While Point A may be used theoretically for dose calculation to the paracervical triangle, the blood supply of the rectum does not lie in its vicinity. Furthermore, accurate location of Point A is impossible because of the elasticity and mobility of pelvic structures, the lateral displacements of the uterus, and distortion of the fornices by tumor. Point A on the right and left sides usually differs in position and in dose received. A more tenable view, expressed by Fletcher et al., Kottmeier, and Lederman (3, 4, 6, 7), holds that radiation injuries of the bladder and rectum are related to the dose received by these structures rather than to the dose at Point A. The Stockholm applicators, on the other hand, are designed to cover the entire surface of the cervical tumor and to pack the radium as far as possible away from the rectum and bladder. The marked individualization of treatment in the Stockholm method, which employs many sizes of vaginal applicators, has made it difficult for others to follow the method. We have designed applicators based on those used in Stockholm in an endeavor to simplify the technic. Radium sources While any one of a variety of radioactive sources may be suitable for the purpose, calculations are easier with 10 mg radium sources 1 cm in overall length. For simplicity we have employed 2.5 mg, 5 mg, and 10 mg radium sources. Each has an active length of 7 mm and is encased in a platinum tube measuring 10 mm in length and 2.5 mm in diameter with a wall thickness of 0.5 mm. The 10 mg sources are distinguished from the 5 mg sources by being gold-plated, while the 2.5 mg sources are gold-plated at one end only. Intrauterine radium The intrauterine radium is the most important source of gamma radiation, especially if the endocervix or corpus is involved.