Radiation units

arunmp's version from 2016-11-14 03:26

Parameter : SI UNIT : NON SI UNIT

Question Answer Column 3
Absorbed DoseGray J/KgRad
Equivalent doseSievertrem
Effective dosetissue exposed



Exposure is a dosimetric quantity for ionizing electromagnetic radiation, based on the ability of the radiation to produce ionization in air.
The exposure is the absolute value of the total charge of the ions of one sign produced in air when all the electrons liberated by photons per unit mass of air are completely stopped in air.
X = dQ/dm
The SI unit of exposure is Coulomb/kilogram C (by kg)
The former special unit of exposure was Roentgen R

Absorbed dose

The absorbed dose D, is the energy absorbed per unit mass. This quantity is defined for all ionizing radiation (not only for electromagnetic radiation, as in the case of the “exposure”), and for any material.
D = dE/dm.
The SI unit of D is the gray Gy.
1 Gy = 1 J/kg.

Equivalent dose

The equivalent dose H is the absorbed dose multiplied by a dimensionless radiation weighting factor, wR which expresses the biological effectiveness of a given type of radiation
H = wR × D
To avoid confusion with the absorbed dose, the SI unit of equivalent dose is called the sievert (Sv).

Effective dose

Radiation exposure of the different organs and tissues in the body results in different probabilities of harm and different severity
To reflect the combined damage, Effective dose E is defined as the summation of tissue equivalent doses (HT), each multiplied by the appropriate tissue weighting factor wT.
E = Σ wT × HT
The unit of effective dose E is sievert (Sv).
For each organ there is tissue equivalent doses ,for bone marrow 0.12 and gomads its 0.08