Radiation Quatities Flashcards
Reddening of the skin caused by overexposure to radiation
Radiodermatitis
Unit for measuring radiation exposure (1900-1930)
Skin Erythema Dose
Quantity of radiation that causes diffuse redness over an area of skin
Skin Erythema Dose
Amount of absorbed radiation corresponds to a modern dose of several dose
Skin erythema dose
Dose of radiation below which an individual has a negligible chance of sustaining specific biological damage
Threshold dose
A radiation dose to which occupationally exposed persons could be continuously subjected without any harmful acute effects
Tolerance Dose (1930)
Tolerance dose required per day
0.2 roentgen/day
In 1936, Tolerance dose required per day
0.1 roentgen/day
Replaced the tolerance dose for radiation purposes
Maximum permissible dose
Indicate the largest dose of ionising radiation that occupationally exposed person was permitted that was not anticipated to result in major adverse effects as a consequence of radiation exposure
Maximum permissible dose
Unit for Maximum permissible dose
rem
Express how much Ionization the beam causes in the air through which it travels
Exposure (X)
Unit of exposure
roentgen (R)
The SI unit of radiation exposure
Coulomb per kilogram (C kg-1)
Produces 2.08 x 10^9 ion per cm^3 of air at standard temperature and pressure (STP)
1 roentgen
1 cm^3 of air at STP has a mass of
0.001293g
STP:
1 atmosphere of pressure 0 C (273.15 Kelvin)
Amount of exposure that will produce 2.58 x 10^-4 C per kg of air
Roentgen
Unit of electrical charge
coulomb
One coulomb of charge is produced by
6.24x10^18 ionizations
1 R =
2.58 x 10-4 C/kg
1 C/kg =
3876 R
Amount of energy per unit mass absorbed by the irradiated object
Absorbed dose (D)
As ionizing passes through an object, some of that energy of that radiation is transferred to that medium
Absorbed dose (D)
Responsible for any biological damage resulting from the tissues being exposed by radiation
Absorbed energy
Quantity of radiation energy absorbed per unit mass of tissue
Absorbed dose
Conventional yin for Absorbed dose
rad
Rad is equivalent to
100 ergs of absorbed energy per g of tissue
The SI unit for Absorbed dose
Gray (Gy)
Gray is equivalent to the absorption of
1J of radiation energy per kg of tissue
Gray is named after the scientist
Louis Harold Gray
Radiation quantity that use used to express the radiation concentration delivered to a point
Air Kerma
KERMA
Kinetic Energy Released per unit mass (of air)
Unit of Kerma
J/kg
Absorbed dose in air
Air kerma
The variation in biological harm that is produced in different types of radiation
Equivalent Dose (EqD)
Used to express the biological impact of radiation on persons receiving occupational or environmental exprosures
Dose Equivalent
Personnel exposure in a clinical facility is determined by
Dose equivalent
Conventional unit for dose equivalent
rem
SI unit for dose equivalent
Sievert
Factor by which the absorbed dose must be multiplied to obtain a quantity that expressed on a common scale for all ionizing radiation
Radiation Weighing Factor
Radiation quantity for expressing relative risk to humans both patients and other personnel
Effective dose
ICRP multiplier used to determine the effective dose from the equivalent dose in one or more organs or tissues
Tissue weighing factor
Represent radiation harm for which there is no threshold
Probabilistic Effect
Dose limits for occupational exposure
Annual - 50mSv
Cumulative - 10mSv
Eyes - 150mSv
Skin hands feet - 500mSv
Dose limit for public, the annual dose limit is
One-tenth that of radiation workers
Use to describe a beam of x-radiation fall into two general categories
Radiation Quantities
