What is the threshold for acute radiation syndrome (ARS)?

The threshold for acute radiation syndrome (ARS) is approximately 1 Gray (Gy). At this level of radiation exposure, individuals may begin to exhibit significant biological effects, including symptoms such as nausea, vomiting, and fatigue, often occurring within hours of exposure. This is due to the impact of ionizing radiation on rapidly dividing cells in the body, particularly in the bone marrow, gastrointestinal tract, and other tissues.

While lower doses of radiation may cause some cellular damage, the manifestation of ARS typically requires exposure at or above the threshold of around 1 Gy. Understanding this threshold is crucial for recognizing and managing the effects of radiation exposure in clinical, occupational, or accidental situations.