Development of a Room Specifically Designed for Total-Body Irradiation

The work of Barnes and his associates suggested a possible new approach to the treatment of leukemia. In order to translate their experimental work on the mouse to man, at least two things are necessary: first, an adequate, readily available source of transplantable human bone marrow of a type which will take in the irradiated recipient; second, a source of radiation which will insure a total-body dose of radiation as nearly uniform as possible. A perusal of the available sources of radiation in the northeastern section of the country failed to disclose any available sources that would give a fairly uniform dosage distribution throughout the human body. Consultation with Dr. John Trump of the Massachusetts Institute of Technology, Dr. Dale Trout of the General Electric Company, and Mr. Donald Green of Picker X-ray led to the conclusion that optimum distribution could be obtained only by using two sources of radiation at an angle of 180° to each other. The consultants unanimously agreed that cobalt 60 would be the best source of radiation because of its constant output, the freedom from breakdowns, and the possible need of prolonged (24-hour plus) continuous treatments. In order to include a 72-inch body, from the top of the head to the tips of the toes, either an unusually long room would be necessary or the exit angle of the radiation from the source would have to approach 60° at a distance of 2 meters from each source. Fortunately the thickness of the human body in the lateral projection resembles a double tapered fly line. The decrease in radiation at the foot and head ends, due to the greater distance of these points from the source of radiation, will in part be compensated for by the decreased thickness of the body in these areas. A rotating source of radiation seemed advisable, so that the room could be used for more conventional forms of therapy when not in use for total-body irradiation or in the event of failure of treatment by total-body irradiation plus bone marrow transplantation in man. It was felt that the two sources should be fairly close in the rhm output and that this output should be sufficiently high that a dose of 1,200 r to each side of the body could be delivered in twenty-four hours if such a dose were found to be necessary. For this reason we selected a 1,000-rhm source as the main or rotational source and a 750-rhm industrial type of cobalt unit as the second source. The 1,000-rhm source can be rotated so that the head is close to the wall and the head turned so that the back stop, if used, will not be in the direct beam. The collimating device will have to be removed during treatment in order to obtain a sufficiently wide exit beam. The 750-rhm unit is designed to have a wide exit beam and, since it will not be utilized for more conventional therapy, it will not be equipped with the usual collimating device.