What immediate health effects can result from high doses of radiation exposure?

Immediate health effects from high doses of radiation exposure primarily include radiation sickness. Radiation sickness, or acute radiation syndrome, manifests soon after exposure to a significant amount of radiation, typically in a single event or over a short period. Symptoms can include nausea, vomiting, diarrhea, skin burns, and damage to the internal organs, which can occur shortly after being irradiated.

This condition results from the radiation's impact on rapidly dividing cells in the body, particularly in the bone marrow, gastrointestinal tract, and skin. The severity of radiation sickness depends on the dose received and the duration of exposure.

While cancer development is a longer-term effect and can indeed be a serious consequence of radiation exposure, it typically does not present immediately. Similarly, although skin burns can occur due to very high doses of radiation, they are often part of the broader spectrum of radiation sickness symptoms rather than a standalone immediate effect. Organ failure can result from severe doses and prolonged exposure but is also more associated with the later stages of acute radiation syndrome, not as an immediate health effect.