Absorbed dose is a measure of the energy deposited in a medium by ionising radiation. It is equal to the energy deposited per unit mass of medium, and so has the unit J/kg, which is given the special name gray (Gy).
Note that the absorbed dose is not a good indicator of the likely biological effect. 1 Gy of alpha radiation would be much more biologically damaging than 1 Gy of photon radiation for example. Appropriate weighting factors can be applied reflecting the different relative biological effects to find the equivalent dose.
The risk of stochastic effects due to radiation exposure can be quantified using the effective dose, which is a weighted average of the equivalent dose to each organ depending upon its radiosensitivity.
Dose: The absorbeddose, given in rads (or in SI units, (Gy) grays), that represents the energy in ergs or Joules absorbed from the radiation per unit mass of tissue.
Furthermore, the biologically effective dose or dose equivalent, given in rem or sieverts, is a measure of the biological damage to living tissue from radiation exposure.
A calculated dose of radiation or a chemical substance that is expected to kill 50% of a population.
Absorbeddose - The fundamental quantity for describing the effects of radiation in a tissue or organ is the absorbeddose.
Absorbeddose is the energy deposited in a small volume of matter (tissue) by the radiation beam passing through the matter divided by the mass of the matter.
Thus, for CT, the absorbeddose in a tissue, in Gy, is equal to the equivalent dose in Sv.
Feeds |
Contact