the unit of absorbed dose is the:
- a- roentgen (C/Kg).
- b- rad (GY).
- c- rem (Sv).
- d- relative biologic effectiveness (RBE).
The correct answer is (b) rad (Gy).
The unit of absorbed dose is the gray (Gy), which is defined as one joule of energy absorbed per kilogram of matter. The rad (radiation absorbed dose) is an older unit of absorbed dose that is still sometimes used, and it is equal to 0.01 Gy.
The roentgen (R) is a unit of exposure, which is a measure of the ionization of air by ionizing radiation. The rem (roentgen equivalent man) is a unit of equivalent dose, which is a measure of the biological effect of radiation. Relative biologic effectiveness (RBE) is a dimensionless factor that describes the relative biological effectiveness of different types of radiation.
Here is a table summarizing the units of radiation:
|
Unit |
Symbol |
Definition |
|
Absorbed
dose |
Gy |
One joule
of energy absorbed per kilogram of matter |
|
Exposure |
R |
The
ionization of air by ionizing radiation |
|
Equivalent
dose |
Sv |
The
biological effect of radiation |
|
Relative
biologic effectiveness |
RBE |
A
dimensionless factor that describes the relative biological effectiveness of
different types of radiation |
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