Acute Radiation Syndrome


It is considered to be very unlikely that an accident at a nuclear power station will lead to cases of ARS in the general public. It may be seen in a few workers as a result of a criticality accident (possible if not very likely at a fuel enrichment plant or where new cores are being built) or an industrial accident involving a powerful source. The symptoms and medical treatment are included here for completeness.

Acute radiation syndrome, or radiation sickness or radiation poisoning, is the name given to the collection of symptoms and effects that the human body suffers if it is subjected to a large dose of ionising radiation to the whole body, or at least the majority of it, in a short period of time. Estimates of the absorbed dose threshold for symptoms to occur range from about 0.3 - 2.0 Gy.

There are three main phases of acute radiation syndrome; prodromal, latent and manifest. The higher the dose received the faster the stages progress and the more severe the symptoms. By following the stages and severity, doctors can estimate the dose that someone received and from that they can plan treatment.

The prodromal (from the Greek for “running before”) stage lasts for up to two days after exposure. Symptoms include anorexia, nausea, vomiting, diarrhoea, fever, headache and increased heart rate. This stage is mild or absent for doses below 1 Gy and more rapid about 2 Gy. Above 10 Gy onset is almost immediate.

During the latent phase the patient can seem to make a recovery as the initial symptoms subside. However, cell replacement function is inhibited and as mature cells reach the end of their life organ function is disrupted.

The manifest illness phase lasts from 21 to 60 days after exposure and is often considered as three parallel effects and their associated symptoms; bone marrow syndrome, gastrointestinal syndrome and cardiovascular syndrome.

Aside: Comparison of lethal radiation dose with thermal energy from a sip of coffee.

A 5 Gy whole body dose of radiation may kill an 85 kg man. In doing so it deposits 5 J/kg x 85 kg = 425 J.

The specific heat capacity of water is 4.18 J/g/ oC.

Coffee drunk at 60oC compared to body temperature of 37 oC provides 4.18 J/g/ oC x (60-37) oC = 96 J/g.

Assuming a sip is about 20g, a sip of coffee provides about 20 g x 96 J/g = 1923 J

A sip of coffee provides more energy than a lethal dose of radiation. Whereas the radiation energy is localised and causes ionisation leading to chemical and physical changes the coffee’s energy is wide spread, low grade and has no significant impact on the body.

More to come