Health

Some parts of the body are especially affected by exposure to different types of radiation. Several factors are involved in determining the potential health effects of radiation exposure. 

They include: 

The most important factor is the dose – the amount of energy stored in the body. As more energy is absorbed into the cells, the greater the damage is. Absorbed dose is the amount of energy absorbed per gram of tissue. 

Hair 
Loss of hair occurs in radiation exposure at 200 REM and more. 

Brain 
Radiation exposure around 5,000 REM or higher can damage the brain. The radiation kills nerve cells and small blood vessels and can cause seizures and immediate death. 

Certain body parts are more affected by exposure to different types of radiation. The thyroid gland is sensitive to radioactive iodine. In sufficient amounts, radioactive iodine can destroy the whole or part of the thyroid. 

When a person is exposed to radiation from about 100 REM, the number of lymphocytes in the blood will decrease, leaving victims susceptible to infections. This is often referred to as mild radiation sickness. Early symptoms of radiation sickness resemble those of flu and may go unnoticed if you do not do blood tests.