What Is an Effective Dose?
Any radiation received by the body almost always involves more than one organ or tissue, and all organs or tissues are not necessarily uniformly exposed to the same dose. The effective dose refers to the sum of the product of the equivalent dose of the tissue or organ and the corresponding tissue weighting factor when the whole body is exposed to non-uniformity. [1]
- Any radiation received by the body almost always involves more than one organ or tissue, and all organs or tissues are not necessarily uniformly exposed to the same dose. The effective dose refers to the sum of the product of the equivalent dose (H T ) and the corresponding tissue weighting factor (W T ) of the irradiated tissue or organ when the whole body is irradiated with non-uniformity .
- The effective unit of an international dose is Joules per kilogram (J · kg -1 ), and the special name is Sievert (Sv). [1]
- The absorbed dose rate D is the radiation absorption of the substance per unit time.
- Although the absorbed dose can be used for various types of radiation to explain how much energy is absorbed by a living organism, it reflects different biological effects. In radiation protection work, the most important thing is that it is produced in the body after exposure. Biological effect, it is necessary to modify the absorbed dose and introduce the concept of equivalent dose. In ICRP Publication No. 60, the equivalent dose H t, r of a certain organ or tissue to R type radiation is defined as:
- H t, r = D t, r ´W r
- In the formula, Dt, r is the average absorbed dose produced by the radiation R in the organ or tissue, and W r is the radiation weighting factor of only the type of radiation, which is a dimensionless quantity. When the unit of absorbed dose is J / Kg, the legal unit of equivalent dose is Sievert (Sv), 1Sv = 1J / Kg (Sievert is a very large unit, so milliSievert (mSv) is usually used, and 1mSv = 0.001Sv. In addition there are micro sieverts (Sv), 1Sv = 0.001mSv). The names of micro-sievert and milli-sievert are widely used. [1]
- Radiation weighting factor Wr describes the effect of radiation type and energy on biological effects.
- After nuclear radiation enters the atmosphere, different rays in the air have different effects on nuclear radiation. For example, the neutron radiation weighting factor is 5 to 20, the alpha radiation weighting factor is 20, and the unit of equivalent dose is millisievert (millisievert mSv), micro sievert (Sv). But in ordinary living environment
- The effective dose E is the equivalent dose of a uniformly irradiated body. The tissue weighting factor W t describes the contribution of different organs and tissues to hazards throughout the body during irradiation (ICRP Publication No. 60 of 1996 replaced the previously used relative risk with the tissue weighting factor Wt