Changes

The tissue weighting factors are needed because different organs have different levels of sensitivity to radiation, even if the equivalent dose is the same. Effective dose is expressed in sieverts (Sv), or, more frequently, millisieverts (mSv) which are 1/1000th of a sievert. This is the most frequently used dose in radiological protection. Unless you see mention of a specific organ, a "dose" in Sv or mSv is the effective dose. In the simplest cases, for uniform whole-body exposure to gamma (photon) or beta (electron) radiation, the radiation weighting factor is 1, and the tissue weighting factors add up to 1, and therefore, for example, an absorbed dose of 1 mGy equals an effective dose of 1 mSv.

==Dose Limits==