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Shells33
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In what measurement is radiation exposure reported?
roentgen equivalents man (REM)
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What is REM?
the measure of biologic damage from radiation adjusted to apply to all tissues
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What are the two categories of radiation?
ionizing, non-ionizing
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What are the 2 types of ionizing radiation?
- particulate
- electromagnetic
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What are the two types of particulate ionizing radiation?
alpha and beta particles
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What are the two types of electromagnetic radiation?
gamma and X-rays
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What is the difference between gamma rays and x rays?
gamma rays are from a natural source, x rays are man made
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As the wavelength of an electromagnetic wave shortens, its energy _____
increases
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Where are alpha and beta particles mainly used?
nuclear med
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Does an alpha wave lost its energy in a short or long amount of time?
short
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What stops an alpha wave?
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How dangerous is external exposure? how about internal?
- external - not dangerous
- internal - dangerous if inhaled or ingested
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How does a beta particle compare to an alpha particle?
- longer laster
- lighter in weight
- can be stopped by thin sheet of plastic
- can travel through 2 cm tissue externally
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Where are beta particles used?
- PET scan
- Strontium 90 radiation for eye CA
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How do electromagnetic waves behave?
like waves and a particle - cannot bend around corners
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What is the energy and ability to penetrate of gamma rays?
high energy, highly penetrating
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What stops gamma rays?
lead or concrete
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Where are gamma rays used in medicine?
cardiac scans, V/Q scans, Thyoid uptake of iodine 123
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How are x-rays expressed?
milliampere-seconds (mAs)
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How does the beam intensity of an X-ray relate to its distance from target?
inversely proportional to the square of its distance
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what does mAs tell you about an X-ray?
the QUANTITY of x rays
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what does kilovolt peak (kVp) tell you about x rays?
- the QUALITY of X-ray
- increased kVp = increased penetrability
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As kVp increases, scatter ____
increases
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What is an early or deterministic dose? What are examples of early radiation exposure?
severity of symptoms are r/t to dose. cataracts, skin injury (sunburn)
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What is a late effect or stochastic exposure?
from repeated low doses of radiation over long periods. severity of response is NOT related to intensity of dose.
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What tissues are most radiosensitive?
WBC, bone marrow, intestinal epithelium, reproductive cells
sensitivity directly proportional to reproductive activity/cellular metabolic activity rates
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What are the least radiosensitive tissues?
mature RBC's, muscle cells, mature bone and cartilage
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What is the max annual occupational radiation exposure?
5 REM
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How do you protect yourself against radiation?
Time, Distance, Shielding
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What is the recommended minimum distance from the patient being exposed to radiation?
- 3 ft
- 6 ft = 2.5 mm of lead
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What does LASER stand for?
Light Amplification by Stimulated Emission of Radiation
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What are the 3 ways laser light differs from visible light?
- 1) Monochromatic (one wavelength)
- 2) Coherent (oscillates in same phase)
- 3) Collimated (narrow, parallel beam)
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What are the 3 types of lasers?
CO2, Nd:YAG, Argon
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Which lasers are invisible to the eye?
CO2 and Nd:YAG
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Where does the CO2 laser damage? What type of glasses should you wear?
cornea only. regular glasses with side guards.
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What does the Nd-YAG laster damage? What type of glasses should you wear?
- Retina
- opaque green or clear with special coating
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What do the KTP and Argon lasers damage? What type of glasses should you wear?
- KTP: retina, red filter eye wear
- Argon: retina, opaque orange eyewear
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How do you protect the patient's eyes from the laser?
saline moistened gauze and laser shields.
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