ABSTRACT
Ionizing radiation doses of more than 0.50 Gy delivered to the whole body in a single dose can be deœned as a high dose. The effects of high doses have been studied extensively in animal models; however, data on the effects of high doses of radiation in humans primarily come from populations exposed to the atomic explosions in Hiroshima and Nagasaki during World War II. These studies have been described in detail in books.1-3 Before discussing acute radiation damage in humans, it is important to understand how radiation initiates damage, and why some cells are more radiosensitive than others (concept of radiosensitivity).
