While roentgen therapy is recognized as the best symptomatic treatment available for leukemia, Hodgkin's disease, and similar conditions, there is apparently no standard method of irradiation. The details appear to differ in some respects with each roentgenologist. The present study was undertaken to determine the actual results of treatment and, if possible, to account for the remarkable difference in the outcome in different patients. The physician tells the roentgenologist: “This patient has leukemia” (or Hodgkin's disease, or some related condition) and asks: “Will you treat him?”. The resultant treatments are of many types. The case histories of 980 patients with diseases of the blood and blood-forming organs, receiving roentgen therapy, were reviewed to note the effect of different factors on the results. The diseases included various stages of myelogenous, lymphatic, monocytic, and atypical-cell leukemias, types of Hodgkin's disease, and lymphosarcoma. Statistical data will be published in another ...