Chapter 4 Flashcards
Date x-rays were discovered
November 8, 1895
Who discovered x-rays
Wilhelm Conrad Roentgen
What type of tube was used during the discovery of x-rays
Crookes tube
What was the paper coated with during the discovery of x-rays
Barium platinocyanide
What was the first x-ray picture of
Roentgen’s wife’s left hand
Who was the first fatality from x-rays and when
Clarence Dally in 1904
Who invented the fluoroscope
Thomas Edison
Types of somatic damage
Radiodermatitis
Cancer
Blood disorders
What committee was formed to create methods of reducing radiation exposure
British X-ray and Radium Protection Committee in 1921
What unit was used to measure radiation dose from 1900 to 1930
Skin Erythema Dose
Skin Erythema Dose corresponds to what radiation unit today
Gray
Purpose of the First International Congress of Radiology
Radiologists from all over the world collaborated on radiation quantities and units
Where and when was the First International Congress of Radiology held
London, England in 1925
Where and when was the Second International Congress of Radiology held
Stockholm, Sweden in 1928
Early Deterministic Somatic Effects
Nausea
Fatigue
Redness of the skin
Intestinal disorders
Fever
Blood disorders
Shedding of skin
Late Deterministic Somatic Effects
Cataract formation
Fibrosis
Organ atrophy
Loss of parenchymal cells
Reduced fertility
Sterility
Late Stochastic Effects
Cancer
Genetic effects
What committee was formed to formulate recommendations for radiation control
US Advisory Committee on X-ray and Radium Protection
What was recommended as a tolerance daily dose limit in 1934
.2R/day
What was recommended as a tolerance daily dose limit in 1936
.1R/day
What became the internationally accepted unit of measurement for exposure in 1937
R
US Advisory Committee of X-ray and Radium Protection became known as the:
National Council on Radiaiton Protection and Measurements (NCRP)
What replaced tolerance dose in the early 1950s
Maximum Permissible Dose (MPD)
How is exposure measured
C/kg
How is Air Kerma measured
Gray
How is Abosrbed Dose measured
Gray
How is Equivalent Dose measured
Sievert
How is Effective Dose mesaured
Sievert
Total electrical charge of one sign (all pluses or all minuses) per unit mass that x-ray and gamma ray photons with energies up to 3 MeV generated in dry air at standard temperature and pressure
Exposure
Radiation quantity that expresses the concentration of radiation delivered to a specific area, such as the surface of the human body
Exposure
What is used to measure radiation exposure
Free-air ionization chamber
The basic unit of electrical charge
Coulomb
The SI unit of electrical charge
Ampere
What does the Coulomb represent
Amount of electrical charge flowing past a point in a circuit in 1 second when an electric current of 1 amp is used
What unit of measurement is used for x-ray eqiupment calibration
C/kg
SI quantity that can be used to express radiation concentration transferred to a point
Air Kerma
Air Kerma is gradually replacing what term
Exposure
What does Air Kerma measure
Radiation intensity in air
Air Kerma is an acronym for Kinetic Energy Release in:
Material
Matter
Per unit Mass
How is Air Kerma expessed in metric units
J/kg
How is Gy used differently to indicate kinetic radiation energy absorbed in air verus tissue
Gya
Gyt
The sum total of Air Kerma over the exposed area of the patient’s surface
DAP
What unit is DAP measured
mGy-cm²
Amount of energy per unit mass absorbed by an irradiated object
Absorbed Dose
Responsible for any biologic damage resulting from exposure of the tissues
Absorbed Dose
The amount of energy absorbed by a structure depends on:
- Atomic number
- Mass density
- Energy of photon
SI unit of Absorbed Dose is
Gray
Centi is what fraction
1/100
Milli is what fraction
1/1000
Micro is what fraction
1/1,000,000
How many rad = 1 cGy
1 rad = 1 cGy
Total amount of radiant energy transferred by ionizing radiation to the body
Surface Integral Dose
Surface Integral Dose was also known as
Exposure Area Product
Equivalent SI unit for Surface Integral Dose is
Gy-m²
Quantity factor for X-ray
1
Quantity factor for Beta particles
1
Quantity factor for Gamma particles
1
Quantity factor for Fast neutrons
20
Quantity factor for alpha particles
20
Amount of energy transferred on average by incident radiation to an object per unit length of track through the object
Linear Energy Transfer
LET is expressed in units of
keV/μm
Radiation with a ____ LET transfers a large amount of energy into a small area
High
What is used to determine Equivalent Dose
Radiation Weighting Factor
Used for radiation protection purposes to account for differences in biologic impact amount various types of ionizing radiation
Radiation Weighting Factor
The product of the average absorbed dose in a tissue or organ in the human body and its associated WR chosen for the type and energy of the radiation in question
Equivalent Dose
Takes into account the relative detriment to each specific organ and tissue
Tissue Weighting Factor
A value that denotes the percentages of the summed stochastic risk stemming from irradiation of tissue to the all-inclusive risk
Tissue weighting factor
What is the summed stochastic risk
Cancer plus genetic risk
Provides a measure of the overall risk of exposure to ionizing radiation
Effective dose
Incorporates both the effect of the type of radiation used and the variability in radiosensitivity of the organ or body part irradiated
Effective dose
Used in radiation protection to describe internal and external dose measurements
Collective EfD
Used to describe radiation exposure of a population or group from low doses of different sources of ionizing radiation
Collective EfD
Radiation unit for Collective EfD
Person-sievert
Product of the average EfD for an individual belonging to the exposed population or group and the number of persons exposed
Collective EfD
Radiation dosimetry quantity that was defined by the NRC to monitor and control human exposure to ionizing radiation
Total Effective Dose Equivalent (TEDE)
The sum of the effective dose equivalent from external radiation exposure and a quantity called committed effective dose equivalent from internal radiation exposures
Total Effective Dose Equivalent
Used to monitor dose for personnel such as nuclear medicine technologists and interventional radiologists
Total Effective Dose Equivalent
Exposure measures what type of radiation
X-rays
Gamma rays
Air Kerma, D, EqD, and EfD all measure what type of radiation
All ionizing radiation
1 SI exposure unit equals
1/(2.58x10^-4) R
Received quantity of radiation that causes diffuse redness over an area of skin after irradiation
Skin Erythema Dose
Radiation dose to which occupationally exposed persons could be subjected without any apparent harmful acute effects
Tolerance dose
A dose of radiation lower than which an individual has a negligible change of sustaining specific biological damage
Threshold dose
What report describes the radiation weighting factor as a dimensionless factor that was chosen for radiation protection purposes to account for differences in biologic impact among various types of ionizing radiation
Report No. 116
