What is the median lethal dose of radiation considered to be?

The median lethal dose (LD50/30) refers to the dose of radiation that is lethal to 50% of the exposed population within 30 days. This value can vary based on factors such as the type of radiation, the exposure duration, and individual susceptibility, but a widely accepted estimate for humans is around 400 to 500 roentgens. However, higher doses can lead to increased lethality, and research often suggests that doses ranging from about 550 to 750 roentgens result in significant mortality rates in a population.

Selecting the range of 550 to 750 roentgens as the median lethal dose encompasses the high-end estimates that have been established through studies on radiation exposure effects. While estimates can vary, this range reflects a consensus that such exposure levels are indeed critical thresholds where the probability of death increases significantly, underscoring the severe biological consequences of high radiation doses.