Radiation sickness gets better before it gets worse

Radiation is energy, travelling as energy waves or high-speed particles,
occurring naturally or made by people. It comes in two kinds:

Background radiation is around us all the time, mostly forming naturally
from minerals in the ground, soil, water and our own bodies, and some arriving
from outer space and the sun. Human-made sources include x-rays, radiation
therapy for cancer, and electrical power lines.

What it does

Radiation has been present throughout human evolution, so **our bodies are
built to handle the low levels we meet daily**. Too much damages tissue by
changing cell structure and damaging DNA, which can cause serious problems
including cancer.

How much damage depends on:

• The type of radiation
• The dose
• How you were exposed — skin contact, swallowing, breathing it in, or
  rays passing through the body
• Where it concentrates in the body and how long it stays
• How sensitive your body is. A fetus is most vulnerable; infants,
  children, older adults, pregnant women and people with compromised immune
  systems are more vulnerable than healthy adults

Low environmental levels cause no immediate effects, but slightly increase
overall cancer risk.

The pattern of acute radiation syndrome

A lot of radiation over a short period — a radiation emergency — causes skin
burns and can cause acute radiation syndrome, "radiation sickness". Its
course is what makes it so dangerous:

1. Headache and diarrhoea, usually starting within hours.
2. The symptoms go away, and the person seems healthy for a while.
3. They get sick again — and how soon, which symptoms, and how severely
   all depend on the dose received.

In some cases ARS causes death in the following days or weeks.

Step 2 is the trap. Apparent recovery after a known exposure is part of the
syndrome, not the end of it, and it is exactly when someone is most likely to
decide they are fine.

Treatment

Before treating, clinicians work out how much radiation the body absorbed:
questions about symptoms, blood tests, sometimes a measuring device, and
details of the exposure — what type of radiation, how far from the source, how
long.

Treatment focuses on **reducing and treating infections, preventing
dehydration, and treating injuries and burns**. Some people need treatments to
help bone marrow recover its function. For certain types of radiation
there are treatments that limit or remove contamination inside the body.

Reducing your exposure

• Medical tests. If a test uses radiation, ask about risks and benefits —
  sometimes a different test will do. If you do need it, **choose an imaging
  facility that monitors and reduces the doses it gives patients.**
• Mobile phones. Scientific evidence has not found a link between
  phone use and health problems in humans, and more research is needed. If you
  are still concerned, spend less time on the phone and use speaker mode or a
  headset to put distance between your head and the handset.
• Radon. If you live in a house, test the radon levels and fit a radon
  reduction system if needed.
• In a radiation emergency: get inside a building, stay inside with all
  windows and doors shut, and follow the advice of emergency responders and
  officials.

Source: Environmental Protection Agency, via MedlinePlus.