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Radiation quantities and units

Terms in this set (40)

Roentgen and the Coulomb/kilogram (C/kg) are both units used to measure...
exposure
Absorbed dose is measured in what 2 units?
Rad, Gray (Gy)
Rem and Sievert (Sv) are units that are used to measure....
Dose equivalent
What is defined as the amount of energy per unit mass absorbed by the irradiated object
absorbed dose
the total electric charge per unit mass that x-ray and gamma ray photons with energies up to 3 MeV generate in dry air only is defined as...
exposure
True or false? Absorbed dose equivalent allows for the differences in ionizing abilities of different radiations and how they contribute to biologic damage
true
Absorbed dose equivalent is equal to...
abosrbed dose x quality factor (QF)
What is the quality factor?
it is the modifying factor used in the calculation of dose equivalent to determine the ability of a dose of any kind of radiation to cause biological damage
(x/gamma/beta = 1
Alpha = 20)
Dose equivalent provides a method with which to calculate therealistic ___
absorbed dose for all types of ionizing radiation (including protons and neutrons as well as x-rays)
True or false? Equal absorbed doses of different types of radiation produces different amounts of biologic damage in body tissue
true
100 rad absorbed dose of alpha particles causes less damage than a 100 rad absorbed dose of x-rays. True or false?
false. (more!)
What is L.E.T.?
linear energy transfer
What is defined as the amount of radiant energy transferred to an irradiated object per unit length of travel through the irradiated object
L.E.T. (linear energy transfer)
Radiation with a high LET transfers a ___ amount of radiation into a small area
high
Radiation with a high LET can do more damage than radiations with a low LET. True or falso?
true
High LET radiation also has a high ____
quality factor
x-ray, gamma, beta quality factor =
1
alpha particle quality factor =
20
If a person receives 5 rad of x-radiation, the dose equivalent in rem =
5 (5 rem=5 rad X 1 -- 1 is the QF for x-radiation)
If a person receives 5 rad of alpha particles, the dose equivalent in rem =
100 (100 rem = 5 rad X 20 --20 is the QF for alpha particles)
Alpha particles are ___ times more ionizing than x gamma, and beta radiation
20
(Exposure) What does Roentgen measure?
measures X and gamma radiation only (up to 3 MeV)
Roentgen (exposure) is measured in ___
dry air
(Absorbed dose) Rad =
any absorber, any type of radiation
(dose equivalent) Rem is measured in/measures/refers to
measured in body tissue, measures biologic effects, all types of radiation
The SI unit of measurement for exposure is __
coulomb/kg
Absorbed dose is measured in what SI unit?
Gray
Sievert is the SI unit that is used in measurements of __
dose equivalent
Rad/Gray indicates the amount of ___
radiant energy transferred to an irradiated object by any type of ionizing radiation
Rad/Gray is equivalent to an energy transfer of ___ ergs per gram of irradiated object
100 (100 erg = 1 rad)
Gray (S) is defined as
an energy transfer of one joule per kilogram of irradiated object
to convert rads to gray, divide the number of rads by 100
100 rads = 1 gray (1 rad = 1/100 Gy)
To convert gray to rads, multiply the number of gray by 100
(1 gray = 100 rads)
Roentgen is defined as __
the photon exposure that produces under standard conditions of pressure and temperature a total positive or negative ion charge of 2.58 x 10^-4 C/kg of dry air
one roentgen = ___ C/kg
2.58 X 10^-4
___rem is the absorbed dose of any type of ionizing radiation that produces the same biological effect as one rad of x-radiation.
one
Absorbed dose (Rem/Sievert) in rad is converted to rem by the use of a modifying factor known as the ____
quality factor rem=rad x QF.
SI unit of dose equivalent is the ___
Sievert
To convert Sievert to rem, multiply the number of Sievert by 100
1 Sievert = 100 rem
To convert rem to Sievert, divide the number of rem by 100
100 rem = 1 Sievert (1 rem 1/100 Sievert (Sv))
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