Acute radiation syndrome, also known as radiation poisoning, radiation sickness, or radiation toxicity, is a constellation of health effects that are present within 24 hours of exposure to high amounts of ionizing radiation, which can last for several months. The term acute refers to immediate medical problems rather than ones that develop after a prolonged period.
Radiation sickness is caused by exposure to a large dose of ionizing radiation over a short period of time, typically greater than about 0.1 Gy/h. This might be the result of a nuclear explosion, a criticality accident, a radiotherapy accident, escape of radioactive waste, human error in a nuclear reactor, etc.
A survivor of acute radiation syndrome
A photograph of an 11-year-old girl, who was 2 kilometers away from the Hiroshima bombing site, recovering from acute radiation syndrome.
Radiation Symptoms
The onset and type of symptoms depends on the radiation exposure. Relatively smaller doses result in gastrointestinal effects, such as nausea and vomiting, and symptoms related to falling blood counts, such as infection and bleeding. Relatively larger doses can result in neurological effects and rapid death. Treatment of acute radiation syndrome is generally supportive with blood transfusions and antibiotics.
Similar symptoms may appear months to years after exposure as chronic radiation syndrome when the dose rate is too low to cause the acute form. Radiation exposure can also increase the probability of developing some other diseases, mainly different types of cancers. These diseases are sometimes referred to as radiation sickness, but they are never included in the term acute radiation syndrome.
Classically, acute radiation syndrome is divided into three main presentations: hematopoietic (affecting the bone marrow), gastrointestinal (following radiation exposure to the stomach and intestines), and neurological/vascular (after exposure to the brain). The speed of onset of symptoms is related to radiation exposure, with greater doses resulting in a shorter delay in symptom onset.
The best prevention for radiation sickness is to minimize the exposure dose or to reduce the dose rate.