When all sites and types of cancer are included, the cure rate from currently accepted methods of treatment does not exceed 25 per cent. This means that about 75 per cent of all cancer victims must be considered incurable and can be treated only palliatively for prolongation of useful life or relief of symptoms, or both. The value of radiotherapy as a palliative agent is not universally appreciated. There is often a lack of interest in the hopeless or incurable patient and either no active treatment is given or only meaningless token therapy. Recently, renewed interest has been displayed in the use of grids for roentgen therapy of advanced cancers. Grids have been used in roentgen therapy since 1909, when Alban Köhler (1) made his first report. Later, in 1933, Liberson (2) suggested the use of a metallic lead grid and worked out the biological and physical aspects which are, for the most part, valid to this day. Others, including Haring (3), Grynkraut (4), and Jolles (5) have also suggested the use of gri...