CONCEPTS AND FUNDAMENTALS OF RADIOLOGIC SCIENCE Flashcards
What is matter?
Anything that occupies space and has mass.
What are atoms?
The building blocks of matter.
The quantity of matter as described by its energy equivalence.
mass
Define weight.
The force exerted on a body under the influence of gravity.
What is energy?
The ability to do work.
SI unit of energy?
Joules (J).
Unit of energy used in radiology?
electron volt (eV).
The ability to do work by virtue of position.
potential energy
Define kinetic energy.
The energy in motion.
The energy released by a chemical reaction.
chemical energy
The energy in motion at the molecular level.
thermal energy
Define nuclear energy.
The energy contained within the nucleus of an atom.
The type of energy used in x-rays.
electromagnetic energy
What does the Theory of Relativity state?
Matter and energy are interchangeable.
Formula for matter-energy equivalence?
E=mc².
Define radiation.
The energy emitted and transferred through space.
Radiation emitted by the sun.
visible light
What does “exposed” or “irradiated” mean?
Matter that intercepts and absorbs radiation.
Example of ionizing radiation?
X-rays, gamma rays, and UV light.
The removal of an electron from an atom.
ionization.
Examples of particulate-type ionizing radiation?
Alpha and beta particles.
What is required for a satisfactory x-ray beam?
High voltage and sufficient electric current.
What is natural environmental radiation?
Radiation from cosmic rays, terrestrial sources, and internally deposited radionuclides.
Annual dose of natural environmental radiation?
300 mrem/year.
Largest source of natural environmental radiation?
Radon.
What is man-made radiation?
Radiation from sources like diagnostic x-rays.
Annual dose of man-made radiation?
60 mrem/year.
Largest source of man-made radiation?
Diagnostic x-rays (39 mrem/year).
Who discovered x-rays?
Wilhelm Roentgen.
When were x-rays discovered?
November 8, 1895.
What material was used in Roentgen’s discovery?
Barium platinocyanide.
What is fluorescence?
Emission of visible light during stimulation.
Year Roentgen received the Nobel Prize?
1901
Who developed fluoroscopy?
Thomas A. Edison.
Who was the first x-ray fatality?
Clarence Dally in 1904.
What did William Rollins demonstrate?
First application of collimation and filtration.
Who introduced the Coolidge x-ray tube?
William D. Coolidge in 1913.
Who invented the stationary grid?
Gustav Bucky.
What is the Potter-Bucky grid?
A moving grid introduced in 1921.
Restricting the x-ray beam to reduce scatter and improve contrast.
collimation
What material is commonly used for collimators?
Aluminum or copper.
Reduces x-ray exposure by more than 95%.
intensifying screen
Examples of protective apparel in radiology?
Lead-impregnated gloves and aprons.
When should gonadal shielding be used?
With all persons of childbearing age.
What are protective barriers in radiology?
Lead-lined structures with leaded-glass windows.
Cardinal principles of radiation protection?
Time, distance, and shielding.
Why avoid pelvic x-rays in pregnant patients during the first trimester?
To minimize radiation exposure to the fetus.
What are the three base quantities in physics?
Mass, length, and time.
What are secondary/derived quantities?
Combinations of one or more base quantities.
SI unit of length?
meter (m)
SI unit of mass?
kg
SI unit of time
s
Rate of change of position with time.
velocity
Formula for velocity?
V= d/t
SI unit of velocity?
Meters per second (m/s).
Velocity of light?
3×10
8
m/s or 186,000 miles/s.
Define acceleration.
The rate of change of velocity with time.
SI unit of acceleration?
Meters per second squared (m/s²).
The property of matter that resists a change in its state of motion.
inertia
Newton’s First Law of Motion?
A body at rest stays at rest, and a body in motion stays in motion unless acted upon by an external force.
Newton’s Second Law of Motion
Force equals mass times acceleration (
𝐹
=
𝑚
𝑎
F=ma).
SI unit of force?
Newton (N).
Newton’s Third Law of Motion?
For every action, there is an equal and opposite reaction.
Formula for weight?
Wt=mg
Acceleration due to gravity (SI unit)?
9.9m/s^2
The product of mass and velocity
momentum
SI unit of momentum?
Kilogram meters per second (kg·m/s).
Define work.
Force applied times the distance moved (
𝑊
=
𝐹
𝑑
W=Fd).
SI unit of work?
joule
The rate of doing work
power
SI unit of power?
watt
What does the law of conservation of energy state?
Energy cannot be created or destroyed, only transformed.
What is heat?
The kinetic energy of random molecular motion.
Unit of heat?
calorie
Define calorie.
The heat required to raise the temperature of 1 g of water by 1°C.
Three ways of heat transfer?
Conduction, convection, and radiation.
Heat transfer through a material by direct contact.
conduction
Mechanical transfer of “hot” molecules in a gas or liquid.
convection
What is thermal radiation?
Heat transfer by emission of infrared radiation.
What are the temperature scales?
Celsius, Kelvin, and Fahrenheit.
Formula to convert Fahrenheit to Celsius?
celsius = 5/9 (farenheit - 32)
Formula to convert Celsius to Fahrenheit?
farenheit = 9/5celsius + 32
Formula to convert Celsius to Kelvin?
K = celsius + 273
What are cryogens?
Cooling agents used in MRI, such as liquid nitrogen and liquid helium.
What are radiologic quantities?
Exposure, dose, equivalent dose, and radioactivity.
Unit of radiation exposure?
Roentgen (R) or air kerma (Gya).
Unit of absorbed dose?
Rad or gray (Gyt).
Unit of occupational radiation exposure?
Rem or sievert (Sv).
Unit of radioactivity?
Curie (Ci) or becquerel (Bq).
Define air kerma.
Energy transferred from radiation to air, measured in Gya.
Define gray (Gyt).
Unit of absorbed dose;
1Gyt=100rad.
Unit of equivalent dose, combining radiation type and biological effect.
sievert
Define curie (Ci).
measure of radioactivity.
1 Ci = 3.7 x 10^10 Bq
Prefix for 10^9
Giga
Define diagnostic radiology.
Imaging using x-rays to diagnose diseases.
Diagnostic x-ray equivalencies?
1R=1rad=1rem=1mGya=1mGyt=1mSv.
What is the Coolidge tube?
An x-ray tube introduced by William D. Coolidge in 1913.
What is the Snook transformer?
An interrupterless transformer used in radiology.
A natural radioactive gas and the largest source of environmental radiation
radon
Who invented the moving grid?
Hollis potter
A device combining stationary and moving grids for radiographic clarity.
Potter-Bucky grid
Who developed fluoroscopy?
Thomas A. Edison
Electron emission from a heated filament in an x-ray tube.
thermionic emission
Define isotopes
Atoms with the same number of protons but different numbers of neutrons.
Reduction in x-ray intensity due to absorption and scattering.
attenuation
What does MSCT stand for?
Multislice Spiral Computed Tomography.
When was MRI accepted as a modality?
1980
What is PET?
Positron Emission Tomography, developed in the 1970s.
Define atomic mass unit (amu).
1amu≈1/12 the mass of a carbon-12 atom.
Material that allows x-rays to pass through easily.
radiolucent
Material that absorbs x-rays, appearing white on images.
radiopaque
X-rays scattered back toward the source.
backscatter radiation
An invisible image on film before it is processed.
latent image
X-ray interaction causing a photon to lose energy and change direction.
compton scatterin
What is photoelectric absorption?
Complete absorption of an x-ray photon by an atom.
Define bremsstrahlung radiation.
Radiation produced when electrons decelerate near a nucleus.
What is characteristic radiation?
X-rays produced when an inner-shell electron is ejected, and an outer electron fills its place.
