Changes in Acute Radiation Hazards Associated with Changes in Exposure Geometry

Abstract

The ratios of the mean bone-marrow dose and of the midline abdomen dose to the corresponding exposures were measured for a phantom exposed in a rotational geometry about its vertical axis to broad beams of X- and gamma-radiation incident at angles from − 30° to +75° to the normal to the axis of rotation. The energy of the radiation varied from 0.06 to 0.66 MeV. The ratio of the dose to the exposure was heavily dependent on the irradiation geometry. For many exposure conditions it was shown that the ratio of dose to exposure obtained at normal incidence would not be sufficient to assess the hazard for acute effects of whole-body irradiation.