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Radiation
Energy emitted and transferred through space
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Energy
the ability to do work
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Ionizing radiation
- Any kind of radiation capable of removing an orbital electron from an atom.
- Results in and ion pair.
- includes:x-rays, gamma rays, UV rays
- also includes particulate ionizing radiation: alpha & beta particles
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Ion pair
- ejected electron is the negative ion and
- the remaining atom is a positive ion
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Electromagnetic Waves with frequencies higher than UV light are considered ...
Ionizing radiation
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Three types of Ionizing radiation
can be natural or man made source
- Alpha, can be stopped with paper
- Beta, can be stopped with wood, clothing or aluminum
- Gamma, x-rays lead or concrete
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REM
- unit of radiation equivalent man
- used to express radiation exposure of populations
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3 sources of Natural radiation
- Cosmic
- Terrestrial
- Internally deposited radionuclides
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Cosmic Rays
- Natural environmental radiation
- from sun and stars
- intensity increases with altitude & latitude
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Terrestrial Radiation
- Natural environmental radiation
- from deposits of uranium, thorium and other radionuclides in the earth
- intensity dependent on geology of local area
- Radon is the largest source
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internally deposited radionuclides
- Natural Environmental Radiation
- from the human body
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Dosage of ionizing radiation
Natura and manmade
- Natural Environmental aka background
- annual dose approx 300 mrem
- Man-made
- annual dose approx 60 mrem
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x-ray interaction with matter in 5 ways,
which 2 are important to diagnostic radiography?
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Differential absorption occurs because of...
- compton scattering
- photoelectric effect
- x-rays transmitted through the patient
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