injuries and poisoning
Radiation Injury
Measurement of radiation
The amount of radiation is measured in several different units. The roentgen (R) is a measure of the ionizing ability of radiation in air and is commonly used to express the intensity of exposure to radiation. How much radiation people are exposed to and how much is deposited in their body may be very different. The gray (Gy) and sievert (Sv) are measures of the dose of radiation, which is the amount of radiation deposited in matter, and are the units used to measure dose in humans after exposure to radiation. The Gy and Sv are similar, except the Sv takes into account the effectiveness of different types of radiation to cause damage and the sensitivity of different tissues in the body to radiation. Low dose levels are measured in milligrays (mGy, 1 mGy =1/1000Gy) and millisieverts (mSv, 1 mSv =1/1000Sv). 