J Clin Endocrinol Metab 82 (7): 2182 - 2191, 1997. doi: 10.1210 / jcem.82.7.4041 Prognosis for Radiation Exposure and Contamination Without medical care, the LD-50/60 (dose expected to be fatal to 50% of patients within 60 days) for whole-body radiation is about 3 Gy; exposure to > 6 Gy is nearly always fatal.