The doses are measured in gray (Gy) for matteria or Sievert (Sv) for biological tissue. The dose refers to the amount of energy or damage deposited in the matter, and should not be mistaken from the unit of radioactive activity (bequerel, Bq). The doses can verry well be measured in another place other then where the radioactive decay occurred.
The worldwide average background dose for a human being is around 3.5 mSv a year [1], mostly from cosmic radiation and natural isotopes in the earth.
There are several ways of measuring doses from ionizing radiation. Workers that come in contact with radioactive substances or use radioactivity routinely carry personell dosimeters. Those dosimeters are of such a material that they can be used in Termo Luminescence Dosimetry (TLD) or Optically Stimulated Luminescence (OSL). In radiotherapy patient dosimeters are used to monitor the doses given to the patient. The equipment used in radiotherapy (Linear particle accelerator in external beam therapy) are routinely calibrated using ionization chambers.
After the attac on World Trade Center September 11th 2001, there has been an increasing interest in the field of Emergency Prepearedness within the field of detecting and monitoring ionizing radiation.
This article is a stub. You can help Wikipedia by fixing it.