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The hazards involved in the handling of naked radium in the radium dial painting industry are surveyed. The suggested tolerance values of 0·1 microgramme of radium in the body (or alternately 10−12 curie/litre in the expired air) and 10−10 curie/litre of radon in the atmospheric air of workrooms are discussed and results given of measurements on workers and workrooms in the industry.

The planning of treatment for patients with gynaecological cancer undergoing combined intracavitary and external beam irradiation at the Royal Marsden Hospital is described. The purpose of the external beam irradiation is to increase the dose to the parametria and pelvic nodes since these tissues are generally too far from the intracavitary 137Cs sources to receive a tumoricidal dose. The treatment policy and problems of dosimetry are discussed. The main problem is to combine the two modes of radiotherapy so as to ensure an adequate dose to the required regions and to afford protection to previously irradiated areas. The method of computing the dose distribution from the intracavitary 137Cs sources is described and also how this distribution is used to design protective absorbers for use with the external beam therapy. Different shapes of absorbers are required for cobalt units and linear accelerators because of the different beam characteristics. The way in which these are designed for individua...

The use of radioactive yttrium (90Y) is reviewed as an alternative to 198Au for malignant effusions. Fifteen cases were treated by intracavitary injection of a new compound, colloidal yttrium silicate. Of nine patients surviving longer than one month, six received good palliation for periods ranging from five to 19 months. The intracavitary retention and extracavitary dosage are detailed and compared with those of other yttrium preparations and with gold.

Injections of 150–200 mc of colloidal radioactive gold into the intraperitoneal space and 75–100 mc intrapleurally have been found from clinical experience to be of considerable radiotherapeutic value. It is of importance to consider how far this experience in the millicurie injection required can be transferred to similar treatments with other isotopes, and in particular to the use of colloidal 90Y considered in Section I of this paper. A calculation of the probable doses given, in terms of rads, for some of the various conditions that may occur in practice may provide some contribution to the further development of this type of treatment. The integral dose delivered can readily be calculated from the half-lives of the isotope and the average β energy, but the actual dose delivered to individual tissues will depend as well on the volume of fluid in the cavity and the depth below the surface of the point considered. This variation will generally be different for different isotopes. Doses to the peritoneal...