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Cards (139)

  • Radiation
    Emission of energy through space
  • Radiation
    • Can move as electromagnetic waves or subatomic particles (Wave-Particle Duality)
    • Can be intercepted or absorbed by Matter
    • Matter that intercepts radiation is said to be exposed or irradiated
  • Types of Radiation
    • Non-Ionizing Radiation
    • Ionizing Radiation
  • Non-Ionizing Radiation
    A type of radiation that does not remove electrons from atoms
  • Ionizing Radiation
    A type of radiation that removes electrons from atoms and molecules
  • Sources of Ionizing Radiation
    • Natural Environmental Radiation
    • Man-Made Radiation
  • Natural Environmental Radiation
    • Results in an annual radiation dose of approximately 3 millisieverts
    • Consists of four components: Cosmic Rays, Terrestrial Radiation, Internally Deposited Radionuclides, and Radon
    • Human evolution has been influenced by natural environmental radiation
  • Cosmic Rays
    • Originates in outer space through heavenly bodies such as the sun and stars
    • Source of natural background radiation
    • Composed of particulate (alpha, beta, etc.) and electromagnetic (x-rays, gamma rays, etc.) radiations
    • The intensity of cosmic radiation on Earth increases with altitude and latitude
  • Terrestrial Radiation
    • Results from deposits of Uranium, Thorium, and other radionuclides in the Earth
    • Can be found all throughout nature such as in the soil, water, and vegetation
    • The intensity of terrestrial radiation is highly dependent on the geology of the area
  • Internally Deposited Radionuclides
    • Found inside the human body through the water we drink or the food we eat
    • Have always been with us and contribute an equal dose to humans
    • Examples are: Potassium-40 and Carbon-14
    • 1,000 bananas is equal to 1 chest x-ray
  • Radon
    • The largest source of natural environmental radiation
    • A radioactive gas produced by the natural radioactive decay of uranium
    • Alpha emitter
    • Contributes to radiation dose only to the lungs
    • Can be found in all Earth-based material such as concrete, bricks, and gypsum wallboards
  • Man-Made Radiation
    • Results in an annual dose of 3.2 millisieverts
    • Artificial
    • Used in many ways such as medical procedures, consumer items, and nuclear energy
  • Medical Procedures
    • Diagnostic X-rays
    • Computed Tomography
    • Fluoroscopy
    • PET Imaging (Fluorine-18)
    • Nuclear Medicine Imaging (Iodine-131, Tc-99m, Co-60, etc.)
    • Radiologic Technologists have the responsibility of reducing unnecessary exposure of the patients and personnel
  • Consumer Products
    • Radium Watch Dials (Radium and Tritium)
    • Smoking Tobacco
    • Road Construction Materials (Radon)
    • Electron Tubes
    • Exit Signs
    • Smoke Detectors
    • Camping Lantern Mantles (Thorium)
    • Airport X-ray Systems
  • Groups exposed to man-made radiation sources
    • Members of the public
    • Occupationally exposed individuals
  • Members of the public
    • Any individual not working directly with radiation (civilians)
    • Exposed to consumer products, radiation from nuclear fuel cycle, residual fallout from nuclear weapons and accidents
  • Occupationally exposed individuals
    • Individuals working directly with radiation (Rad Techs, Flight Attendants, Nuclear Reactor Workers)
    • Exposed to working environment such as in radiology and are monitored for radiation exposure with dosimeters
  • Types of Ionizing Radiation
    • Directly Ionizing Radiation
    • Indirectly Ionizing Radiation
  • Directly Ionizing Radiation
    • Includes charged particles that have enough energy to remove electrons or ionize molecules
    • Can cause multiple ionization events
  • Indirectly Ionizing Radiation
    • Includes uncharged particles such as photons or neutrons
    • Occurs from an ionization that sets free a single electron with insufficient energy to produce multiple ionization events
  • Two Basic Types of Radiation
    • Particulate Radiation
    • Electromagnetic Radiation
  • Particulate Radiation
    • Charged subatomic particles (alpha and beta radiation)
    • Subatomic particles carry energy and have mass
    • Primarily produced during radioactivity of an unstable atom
    • Must be in motion and possess sufficient kinetic energy to cause ionization
  • Alpha Radiation
    • Equivalent to a Helium nucleus (Consists of 2 protons and 2 neutrons)
    • Atomic mass is approximately 4 amu
    • Large and exerts great electrostatic force
    • Emitted only from heavy elements
    • Average kinetic energy = 4-7 MeV
    • Ionizes approximately 40,000 atoms for every centimeter of travel through the air
    • Energy is lost quickly because of the amount of ionization
    • Travels 5 cm in air; 100 um in soft tissue
    • Safe if intercepted outside of the body (intercepted by layers of the skin); Intense when intercepted inside the body (Inhaled Radon gas irradiate the lungs)
  • Beta Radiation

    • Differ from alpha radiation in terms of mass and charge
    • Carry a negative charge but differ from electrons by its origin (nucleus)
    • Range is longer than alpha radiation; 10-100 cm in air and 1-2 cm in soft tissue
  • Electromagnetic Radiation
    • A type of radiation that have both non-ionizing and ionizing capabilities
    • Exists over a wide energy range called a an energy continuum
    • Has no mass, but has electrical and magnetic energy changing in a sinusoidal fashion
    • Travels in the form of photons, which is its smallest quantity
    • Its properties include: Frequency, Wavelength, Velocity, and Amplitude
    • The term electromagnetic energy was coined by James Clerk Maxwell who showed that visible light has both electric and magnetic properties
    • Travels at the speed of light (3 x 10^8 m/s)
  • The Electromagnetic Spectrum

    • Radio Waves
    • Microwaves
    • Infrared Radiation
    • Visible Light
    • Ultraviolet Light
  • Radio Waves
    • Described in terms of their frequency
    • Have the longest wavelength and lowest energy
    • Carry signals for television, cellular phones, and radio stations
    • Non-ionizing radiation
  • Microwaves
    • Have wavelengths shorter than radio waves
    • Can be used to heat food, or used in radar
    • Non-ionizing
  • Infrared Radiation
    • Also known as IR
    • Lies between the visible light and microwaves
    • Can be observed in objects producing heat
    • Broken into three categories: Near, Mid, and Far
    • Near = closest to visible light
    • Far = closest to microwaves
    • Non-ionizing
  • Visible Light
    • Described in terms of wavelength
    • The only part of the EM Spectrum visible to the human eyes
    • Occupies the smallest area of the spectrum
    • Have wavelengths ranging from 400 nm to 700 nm
    • Photons of light travel in a straight line but can be deviated by refraction
    • Non-ionizing
  • Visible Light Wavelengths
    • Red = 700 nm
    • Orange = 650 nm
    • Yellow = 600 nm
    • Green = 550 nm
    • Blue = 500 nm
    • Indigo = 450 nm
    • Violet = 400 nm
  • Ultraviolet Light

    • Located between the visible light and x-ray spectrum
    • Responsible for molecular interactions that can cause sunburn
    • Can be both non-ionizing and ionizing
  • Infrared radiation

    Also known as IR, lies between the visible light and microwaves, can be observed in objects producing heat
  • Infrared radiation categories
    • Near
    • Mid
    • Far
  • Near infrared
    Closest to visible light
  • Far infrared
    Closest to microwaves
  • Infrared radiation is non-ionizing
  • Visible light
    Described in terms of wavelength, the only part of the EM Spectrum visible to the human eyes, occupies the smallest area of the spectrum, have wavelengths ranging from 400 nm to 700 nm, photons of light travel in a straight line but can be deviated by refraction
  • Visible light is non-ionizing
  • Visible light wavelengths
    • Red = 700 nm
    • Orange = 650 nm
    • Yellow = 600 nm
    • Green = 550 nm
    • Blue = 500 nm
    • Indigo = 450 nm
    • Violet = 400 nm