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64 Cards in this Set
- Front
- Back
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what does radiation energy need or not need
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a material medium
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there is no difference between
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the type of readiation emitted by natural or man made sources
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radioactive material with long half lives have
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low specific gravity
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alpha radiation
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high energy but short range|travels an inch in air|not an external hazard
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beta radiation
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longer range|10-20 feet in air|can be skin and eye hazard for high activity beta sources
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gamma rays/electromagnetic radiation
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often accompany particle radiation|penetrating radiation|travel 100s of feet in the air|external hazard
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units of decay
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curies (Ci)|decays per minute|Becquerels
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units of decay per second
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Becquerels
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what is a dose of radiation
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when radiations energy is deposited inot our body's tissues
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exposure
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physical unit based on ionization of air
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traditional unit of exposure
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roentgen
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SI unit of exposure
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coulomb/kilogram
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1 R =
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2.58 x 10^-4 C/kg
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dose of radiation
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physical quantity|absorption of energy per unit mass
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traditional unit of radiation
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1 erg/gram
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SI unit of dose
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gray (Gy) =
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dose equivqlent
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unit of biological impact
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effective dose
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unit of risk evaluation
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radioactive material inside the human body
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will cause an internal dose
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typical dose of chest xray
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8 mrem
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ypical dose of dental x ray
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10 mrem
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typical dose of ct
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1,100 mrem
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occupational limit dose for radiation workers
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5,000 mrem/year
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average dose from all sources
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360 rmem/year
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average dose from natural sources
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300 mrrem/year
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what is most important damage
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to DNA|can lead to cell malfunction and death
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our bodies have a highly effiiecint DNA
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repair mechanism
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dose in rads 25-50
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first sign of physical effects|drop in white blood cell count
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dose in rads 100
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threshold for vomiting|within a few hrs of exposure
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dose in rads 320-360
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~50% die within 60 days|with minimal supportive care
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dose in rads 480-540
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~50% die within 60 days|with supportive care
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dose in rads 1,000
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100% dies within 30 days
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radiation somatic effects
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damages to cells passed on to succeeding cell generations
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radiation genetic effects
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damages to genes tat affect future generations
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what are genes
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units of hereditary info that occupy fixed positions (locus) on a chromosome
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how do genes achieve their effect
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by directing the synthesis of proteins
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do somatic and genetic effects show immediate symptoms
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no
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somatic effects: organs which cells proliferate rapidly are easily
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damaged
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translocation
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joining wrong ends of DNA
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1000 mrem = ?rem
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1 rem = ? Rad=
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rule of thumb for risk with radiation: every 1 rem dose, risk increases by
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0.08%
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each rem is assumed to increase cancer risk by
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0.05%
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x rays are photons that originate in
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the energy shell of an atom
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gamma rays are photons that originate in the
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nucleus of the atom
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the shorter the wavelength the
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greater the penetration
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the more dense the object, the
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less penetration
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density
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light or dark processed film
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contrast
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various shades of black, grey, and white in the xray
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radioluscency
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xrays penetrate easily| dark areas
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radiopacity
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xrays do not penetrated easily|light areas
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what are 3 primary considerations when trying to reduce your external exposure to radiation
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time|distance|shielding
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ALARA
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as low as reasonably achievable
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radiosensitive
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breast|bone marrow|mucosal lining of small intestines|fat glands of skin|immune response cells|all stem cells|lymphocytes
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radioresistant
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heart tissue|large arteries|large veins|mature blood cells|neurons|muscle cells
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what measures exposed doses
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dosimeters
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what monitors
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film adges|electroscopes|ionization chambers|biological and chemical dosimeters
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shielding
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placing material between source of radiation and people working nearby
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aplha particles are stopped by
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paper
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beta particles are stopped by
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wood or plexiglass
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gamma and xrays are stopped by
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lead or concrete
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neutrons are absorbed by
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H rich material|concrete
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whole body exposure limit for radiation workers
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5 rem/year
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individual organ limit for radiation workers
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50 rem/year
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very small dose =
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very small risk
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