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94 Cards in this Set
- Front
- Back
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100 rad = ?Gy
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1
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What are 2 effects that may take place when energy is deposited within an atom or molecule?
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excitation and ionization
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True or False, excitation is a permanent vibration
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False, temporary
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True or False, ionization is when an ionized atom is no longer electrically neutral and becomes chemically reactive?
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True.
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Cells are ??% water and ??% other chemicals
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80, 20
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In a cell, the (nucleus, cytoplasm) is more sensitive. Why?
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nucleus, contains DNA
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At what growth phase is a cell most radiosensitive?
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mitosis or just prior to mitosis
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True or False, the cell cycle moves from Mitosis to G1 to S to G2
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True.
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True or False, radiation cannot break chromosomes
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False, it can. This is called chromosome aberration
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Chromosome aberrations occur (before, after) DNA synthesis and chromatid aberrations occur (before, after).
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before, after
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The frequency of aberration is proportional to the dose of what?
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radiation
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True or False, DNA is a key molecule and is "irreplaceable"
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True.
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What is the primary cause of radiation-indiced cell death, genetic mutations, and carcinogenesis?
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damage to DNA
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What are the two theories of the reaction of ionization radiation?
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direct, indirect
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What ionization theory says that radiation transfers energy into biologic molecules like DNA, RNA and forms unstable free radicals
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direct effect
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What ionization theory says that free radicals are very reactive and have short lives
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direct effect
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What ionization theory says that molecuar changes are produced by cross-linking, dissociation and formation of inappropriate bonds
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direct effect
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Direct effect ionizaion radiation accounts for about (1/3, 1/2, 1/4, most) effects of radiation
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1/3.
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Interaction of x-ray with water lead to radiation damage --> ? of water
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radiolysis
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In the radiolysis of water, how many destructive elements are produced?
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4
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What is the name for H*?
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hydrogen (free radical)
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What is the name for OH*?
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hydroxyl (free radical)
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What is the name for HO2?
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hydroperoxyl
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What is the name for H2O2?
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hydrogen peroxide
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What are the two biological effects?
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deterministic, stochastic
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What type of effect requires a certain threshold be met before an effect is seen?
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deterministic effect
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What type of effect does not require a certain theshold for damage to occur?
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stochastic effect
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True or False, Radiation changes in protein, lipids, and carbs at low doses have a profound effect on the cells
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False, no contribution to radiation effects
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What is apoptosis?
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Programed cell death
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What is hormesis?
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low doses of radiation may have beneficial effects by stimulating repair
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What are the two cell types?
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Somatic, genetic
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How are somatic cells different than genetic?
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Somatic cells are not inherited and radiation is contained to the individual; genetic are passed on and radiation can damage the next generation
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Muscle, skin, bone, and blood are considered (somatic, genetic)
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somatic
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Cells that are sensitive to ionizing radiation are (radioresistant, radiosensitive)
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radiosensitive
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Cells that appear to be less harmed by radiation are (radiosensitive, radioresistant)
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radioresistant
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True or False, radioresistant cells are typically cells that are developing and immature
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False, these are mature cells. Developing and immature cells are radiosensitive
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What are the three rules of the Law of Bergonie and Tribondeau with respect to radiosensitive cells?
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1. high mitotic rate, 2. undergo many future mitoses, 3. are most primative in differentiation
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What are two cell types that are exceptions to the Law of Bergonie and Tribondeau?
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Lymphocytes, oocytes (highly differentiated and non-dividing)
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Optic lens, mature erythrocytes, muscle and nerve cells are all have (high, low) radiosensitivity
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low
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Which 2 of these factors does NOT influence radiation effect? (animal species, age, altitude of dose, type of tissue, oxygen, dose rate, penetrating ability of radiation, specific gravity)
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altitude of dose, specific gravity
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What does it mean that radiation effects can be altered by individual variability?
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humans can have differences in radiation effects that are not identified by any physical characteristic
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True or False, children are more suseptible to radiation than adults
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True.
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True or False, the older you get, the less suseptible you are to radiation
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False (sort of a trick question. Children are more suseptible than adults but elderly are also more suseptible than adults)
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True or False, cells that divide slowly are more suseptible to radiation
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False, quickly dividing are more suseptible because there is more opportunity to mutate the cell
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Alpha particles deposit energy in a (short, long) distance and have (less, more) radiobiologic effects than other kinds of radiation
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short, more
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What does LET stand for?
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Linear Energy Transfer
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X-rays can be defined has having (low, high) LET
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low
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True or False, higher LET is more damaging
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True.
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Why is there more cell damage in the presence of Oxygen?
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formation of free radicals
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Dental x-ray units remove (long, short) wavelength x-rays
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long
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What word describes when all energy is given off in a very short period and has more radiobiological effects?
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acute exposure
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What word describes when a small amount of radiation is given off over a prolonged period
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chronic exposure
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True or False, radiobiological effects are higher with chronic exposure
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False, acute exposure
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Dental radiography resembles (acute, chronic) exposure
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chronic
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The extent of long term effects demeonds on the amount of damage to what?
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fine vasculature
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True or False, there are a great number of controlled human studies on genetic mutations
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False. None
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What is the name for the breaking up of the total larger dose into multiple small doses?
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fractionation
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What are three uses of fractionation?
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better repair of healthy cells, greater tumor destruction, increase tumor cell radiosensitivity by increasing oxygen tension
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What are 4 areas of the mouth affected by radiotherapy?
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oral mucous membrane, tase buds, salivary glands, teeth
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When the oral mucuos membrane is affected by radiotherapy, what are some symptoms? Specifically at 2, 3, and 5 weeks.
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redness and inflammation at 2 weeks, mucosiis in 2nd to 3rd week, dificulting eating at 5th week
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How quickly to taste buds generally atrophy after radiation therapy?
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2 to 3 weeks (recover in 60-120 days)
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At what level of Gy are salivary glands completely stopped?
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60 Gy
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True or False, after radiation therapy, salivary gland pH drops to more acidic level
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True.
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True or False, teeth are most afected if radiation occurs during the growth of the tooth
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True.
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If radiation therapy occurs prior to calcification of tooth, what can be destroyed?
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the tooth bud
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(adult, child) teeth are very radioresistant to direct effects
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adult
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True or False, radiation caries are rampant and result from acidic saliva
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True.
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What are the three types of radiation caries?
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superficial lesions, root caries, darkening and wear of crown
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A treatment for radiation caries is to use a daily fluoride rinse as well as a ??? Minute application of ???% NaF gel
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5 minutes, 1%
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What is osteoradiocrosis?
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bone death from radiation
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In osteoradiocrosis, radiation damages what?
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the vasculature
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True or False, osteoradionecrosis is common in the maxilla
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False, mandible
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Osteoradionecrosis causes a non-healing wound with exposure to what?
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bone
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True or False, all sources of infection whuld be removed prior to radiation
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True.
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What does ARS stand for?
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acute radiation syndrome
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What is acute radiation syndrome?
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sequence of events or characteristic changes following high-level, whole body radiation exposure
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in Acute Radiation Syndrome, at what level of Gy do you start to get cario and CNS symptoms?
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50+
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In Acute Radiation Syndrome, what is the name of the first period of 1 to 2 Gy?
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prodromal and latent period
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True or False, radiation exposure dose can increase the rate of symptom onset
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True.
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What is a latent period after x-ray exposure?
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The time between exposure and symptoms
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At what Gy is the Hematopoietic syndrome?
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2 to 7 Gy
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In Hematopoietic syndrome, death can occur in how many days?
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10 to 30
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What syndrome is defined in the range of 7 to 15 Gy? How quickly will death occur?
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gastrointestinal, 10 days
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True or False, once you are exposed to 50Gy, death occurs in 1 to 2 days
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True.
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When is the fetus most sensitive to radiation?
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First three months of pregnancy
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Which x-ray view, maxillary or mandibular, contributes more radiation?
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maxillary
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Gonadal tissues get irradiation from dental radiographs as a result of what?
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scatter radiation
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True or False, Female ovaries get more radiation than male gonads
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False, female ovaries are under more tissue and are more protected
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What is the "unavoidable" radiation dose in the US in microSv?
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3000
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1 FMX is equivalent to how many days of background exposure?
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4 days (35 microSv)
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Dental radiographs have the highest risk of what two types of cancer?
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leukemia and thyroid cancer
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Risk of leukemia from FMX is = to death from ?? Cigarettes or driving ?? Miles
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1.5, 3.6
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People at higher elevation get (more, less) background radiation
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more
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True or False, radiation is going to kill you pretty much no matter what, sorry.
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False.
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