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Ch. 10-12
Radiation Protection
| Question | Answer |
|---|---|
| Stochastic effects of radiation are those that | are “late effects”, may be describes as “all or nothing” effects, do not exhibit a threshold |
| What are the fundamental units of physics from which all other more complex physical units are derived? | Length, mass, time |
| What are x-rays called that have undergone a change in direction after interactions with atoms? | Scattered |
| What safeguards are taken to prevent accidental irradiation in early pregnancy? | patient postings, patient questionnaire, elective booking |
| Which of the following interactions with matter leaves an atom ionized? | compton effect, photoelectric effect, |
| What is the primary purpose of licensure? | to improve patient care |
| Which of the following personnel monitoring devices is capable of providing an immediate reading ? | pocket dosimeter |
| The Geiger counter is capable of detecting which of the following types of radiation? | xrays, gamma rays, beta particles |
| Which of the following is a radiation survey instrument? | cutie pie |
| What is the correct term for a dose response curve when some level of radiation is required before a predetermined response may be measured? | threshold dose response curve |
| If the exposure rate at 2.0 meters from a source of radiation is 18 R/min, what will be the exposure rate at 5 meters from the source? | 2.8 R/min |
| Types of secondary radiation barriers include: | control booth wall, lead aprons, mobile xray barriers |
| The total filtration in an x-ray tube that can generate over 70 kvp must be at least how much? | 2.5 mmAl |
| How many half value layers(HVL) are required to reduce an x-ray beam from 10 mR/mAs to 5 mR/mAs? | 1 |
| Which of the following factors is (are) important in determining thickness of protective barriers? | distance between xray source and barrier, time of occupancy factor, and workload |
| Under what circumstances might a radiographer be required to wear two dosimeters? | during pregnancy, performing vascular radiography |
| Which of the following radiation-induced conditions is MOST likely to have the longest latent period? | leukemia |
| Which of the following are radiation protection measures appropriate for mobile radiography? | the radiographer must be at least 6ft from the patient and xray tube during exposure and the radiographer must announce in a loud voice than an exposure is about to be made and wait for personnel, visitors, and patients to temporarily leave the area. |
| A student radiographer who is under 18 years of age must not receive an annual occupational dose greater than: | 0.1 rem |
| Radiation monitoring instruments depend on which of the following? | ionization |
| How are wavelength and energy related? | inversely |
| The curie is a measurement of which of the following? | number of disintegrations per second |
| Which of the following is most penetrating? | gamma |
| A “controlled area” is defined as one: | that is occupied by people trained in radiation safety, that is occupied by people who wear radiation monitors, and whose occupancy factor is one |
| What is (are) the major effect(s) of deoxyribonucleic acid(DNA) irradiation? | genetic damage and malignant disease |
| What is the annual dose-limit equivalent for the skin and hands of an occupationally exposed individual? | 50 rem |
| If a patient received 3000 mrad during a 15-minute fluoroscopic examination, what was the dose rate? | 0.2 rad/min |
| Each time an x-ray beam scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity? | 1/10 |
| A thermoluminescent dosimetry (TLD) system would use which of the following crystals? | lithium fluoride |
| Sources of secondary radiation include: | leakage radiation, scattered radiation |
| The photoelectric process is an interaction between an x-ray photon and | an inner shell electron |
| In radiation protection, the product of absorbed dose and the correct modifying factor (rad x QF) is used to determine: | rem (sV) |
| According to National Council on Radiation Protection and Measurements (NCRP) regulations, leakage radiation from the x-ray tube must NOT exceed: | 100 mR/hr |
| In which type of monitoring device do photons release electrons by their interaction with air? | ion chamber |
| The symbols 130/56 Ba and 138/56 Ba are examples of which of the following? | isotopes |
| Following exposure to 1 rad of each of the following ionizing radiations, which would result in the greatest dose to the individual? | internal source of alpha particles |
| Which of the following is (are) possible long-term somatic effects of radiation exposure? | carcinogenisis and leukemia |
| Any wall that the useful x-ray beam can be directed toward is called a | primary barrier |
| How does use of rare earth intensifying screens contribute to lowering patient dose? | permits the use of lower mAs |
| Immature cells are referred to as | undifferentiated and stem |
| The unit of measure used to express occupational exposure is the | rem (sV) |
| What is the cumulative dose equivalent limit (formerly MPD) for a 25 year old radiation worker? | 25 rem |
| Which of the following refers to the primary beam after it has passed through the beam restricting device? | useful beam |
| Which of the following interactions will not result in a scattered photon? | photoelectric |
| Which of the following filters would produce an x-ray beam with the highest average photon energy? | 4 mmAl |
| Which of the following x-ray interactions occur most often with x-ray energies between 100 keV and 500 keV? | compton scattering |
| Which of the following are particulate radiation? | alpha and beta |
| The becquerel is the SI unit for which the following traditional units? | curie |
| The source-to-skin distance for stationary fluoro cannot be less than which of the following? | 15 inches |
| Which of the following is an advantage of the TLD over the film badge? | they can record a wide range of energies |
| If an exposure rate of 15R/min is measured at a distance of 3 meters from a source of ionizing radiation, what will be the exposure rate measured at 2 meters? | 33.75 R/min |
| The annual dose limit for occupationally exposed individuals is valid for | beta, x, and gamma radiation |
| The purpose of filters in a film badge is | to measure radiation quality |
| Which of the following is a means of expressing the dose a patient has received from a radiographic procedure? | skin dose, organ dose, whole body dose |
| How much is radiation exposure reduced if the distance between the patient and technologist is doubled? | 4 times less |
| Which of the following could result from excessive radiation exposure to a fetus during the first trimester? | prenatal death, neonatal death, congenital abnormalities |
| Mobile protective barriers should not be used when making exposure above what kilovoltage? | 90 kvp |
| How many times should radiation scatter before reaching the control booth or a mobile protective barrier? | 2 times |
| Which of the following statements concerning the properties of x-rays are true? | they are emitted isotropically |
| The Law of Bergonie and Tribondeau states the cells are more radiosensitive if they are | highly mitotic and undifferentiated |
| Biologic material is MOST sensitive to irradiation under which of the following conditions? | oxygentated |
| Which of the following have an effect on the amount and type of radiation-induced tissue damage? | quality of radiation, type of tissue being irradiated, fractionation |
| What unit of measure expresses the amount of energy deposited in tissue? | rad (Gy) |
| Which stage of mitosis is considered the MOST radiosensitive? | metaphase |
| The dose-response curve that appears to be valid for genetic and some somatic effects is the | linear and nonthreshold |
| Which of the following MOST effectively minimizes radiation exposure to the patient? | beam restriction |
| Gamma rays have | no mass and no charge |
| Which of the following contributes MOST to patient dose? | photoelectric effect |
| A rule of thumb when determining the dose-equivalent limit for the public is that it is usually 1/10 of the occupational limit. What is the annual dose-equivalent limit for the lens of the eye for the general public? | 15 mSv (1.5 rem) |
| How much protection is provided from a 75 kvp x-ray beam when using a 0.25-mm lead equivalent apron? | 66% |
| In which of the following ways can a radiographe reduce the amount of scatter produced? | tight beam collimation, use of lower kilovolts |
| Most radiation detectors operate on which of the following x-ray characteristics? | ionization effects |
| What is the intensity of scattered radiation perpendicular to and 1 meter from the patient, compared to the useful beam at the patient’s surface? | 0.10% |
| Protective devices such as lead aprons function to protect the user from | scattered radiation |
| Several factors are used when determining the appropriate lead thickness in walls. The use factor is based on: | what percentage of time the primary xray beam will be striking a barrier |
| Which of the following is(are) a result of beam restriction due to collimation? | less scatter radiation production, less patient hazard |
| What is the established fetal dose-limit guideline for pregnant radiographers during the entire gestation period? | 500 mrem |
| Early symptoms of acute radiation syndrome include | nausea and vomiting |
| Diagnostic x-radiation may be correctly described as | low energy, low linear energy transfer (LET) |
| If 100R or more is received as whole-body dose in a short period of time, certain symptoms will occur and are referred to as | acute radiation syndrome |
| Which of the following factors can affect the amount or nature of radiation damage to biologic tissue? | radiation quality, absorbed dose, size of irradiated area |
| Which of the following refers to a regular program of evaluation that ensures proper functioning of x-ray equipment, thereby protecting both radiation workers and patients? | quality assurance |
| A secondary barrier protects the technologist from which of the following? | scattered radiation |
| Surfaces within a radiographic room that will be in the direct path of the useful x-ray beam must provide a minimum lead equivalent beam attenuation equal to ____ of lead. | 1 / 16” |
| If an exposure of 16mR is recorded at 1 foot, what would the exposure rate be at 4 feet? | 1 mR |
| What is the exposure rate if 75 mAs results in an exposure of 600 mR? | 8 mR/mAs |
| Which of the following cells would be least sensitive to radiatin? | nerve cells |
| Where do the metabolic functions of a cell take place? | cytoplasm |
| Which of the following types of electrons are most tightly bound in the shells? | the ones closest to the nucleus |
| .Which o thefollwing types of tissue will absorb the most radiation? | bone |
| Which of the following interactions of radiation with tissue results in the complete absorption of the photon? | photoelectric effect |
| with lower frequency, what is the wavelength? | longer the wavelength |
| The effects of radiation to biologic material are dependent on several factors. If a quantity of radiation is delivered to a body over a long period of time, the effect | will be less than if it were delivered all at one time |
| LET is (definition) | a method of expressing radiation quality and a measure of the rate at which radiation energy is transferred to soft tissue |
| what is the effect of relative biologic effectiveness(RBE) at LET increases? | as LET increases, RBE increases |
| . The NCRP recommends an annual effective occupational dose equivalent limit of | 5 rem (50mSv) |
| Which of the following groups of exposure factors will deliver the LEAST amount of exposure to the patient? | 400 ma, 0.25sec, 100 kvp |
| . When water molecules are irradiated, the principal molecular by-products are: | free radicals |
| Which of the following tissues or organs is the MOST radiosensitive? | small bowel |
| The dose of radiation that will cause a noticeable skin reaction is referred to as the | SED |
| The photoelectric effect is likely to occur under which of the following conditions? | with absorbers of high atomic number, with low-energy incident photons, with use of positive contrast media |
| All of the following affect patient dose EXCEPT | focal spot size |
| The use of all of the following will function to reduce patient dose EXCEPT | grid |
| A dose of 25 rad to the fetus during the seventh of eighth week of pregnancy is more likely to cause which of the following? | neurologic anomalies |
| To within what percentage of the SID must the collimator light and actual irradiated are be accurate? | 2% |
| Which of the following is considered the unit of exposure in air? | roentgen (C/Kg) |
| Which of the following are considered especially radiosensitive tissues? | blood-forming organs, reproductive organs, and lymphocytes |
| How many HVLs are required to reduce the intensity of a beam of polyenergetic photons to less than 10% of its original value? | 4 |
| Carcinogenesis, cataratogenesis, and lymphocytic leukemia are all examples of | long-term somatic effects |
| When the exposure rate of an x-ray beam gradually decreases as it passes through matter, it is termed: | attenuation |
| Which of the following body parts is(are) included in whole-body dose? | gonads and lens |
| If the exposure rate to a body standing 5 feet from a radiation source is 12 mR/min, what will be the dose to that body at a distance of 12 feet from the source? | 2 mR/min |
| Irradiation of macromolecules in vitro can result in | main chaing scission, cross-linking, point lesions |
| Which of the following accounts for x-ray beam heterogeneity? | incident electrons interacting with several layers of tungsten target atoms, electrons moving to fill different shell vacancies |
| Transfer RNA carries which of the following to the polysome in order to synthesize a protein? | amino acids |
| What is the process of cell division of the reproductive(germ) cells called? | meiosis |
| Which of the following refers to the single set of chromosomes in a germ cell? | haploid number |
| Of the following blood cell producing organs, which are considered radiosensitive? | spleen, bone marrow, lymphatic nodes |
| If the exposure factors of milliamperes, time, and kilovolts(peak)(kvp), remain the same, a change in which of the other listed factors would affect the dose received by the patient? | source-image receptor-distance |
| Which of the following is a measure of the the rate of energy loss along the track of an ionizing particle? | linear energy transfer |
| What is the minimum level of radiation exposure below which no genetic or somatic damage occurs? | no minimum level is known |
| Which of the following is(are) considered electromagnetic? | xray, gamma |
| . Which of the following cells is the MOST radiosensitive? | erythroblasts |
| Irradiation of water molecules within the body, and their resulting breakdown, is termed | radiolysis |
| Radiation that passes through the tube housing in directions other than that of the useful beam is termed | leakage radiation |
| The tabletop exposure rate during fluoroscopy shall NOT exceed | 10 R /min |
| In the production of characteristic radiation at the tungsten target, the incident electron | ejects an inner shell tungsten electron |
| what are the advantages of beam restriction | less scattered radiation is produced, less biologic material is irradiated |
| . Which of the following is the radiation unit that is used for calibration measurements of diagnostic radiographic equipment? | coulomb per kilogram |
| Which of the following is(are) composed of nondividing, differentiated cells? | neurons and neuroglia |
| Which of the following is(are) helpful in minimizing patient exposure? | accurate positioning, high kv, low mAs, rare earth screens |
| All of the following statements regarding TLDs are true EXCEPT | Following x-ray exposure, TLDs are exposed to light and emit a quantity of heat in response |
| The recommendation of “elective booking” states that elective abdominal radiographic examinations on women of reproductive age should be limited to the | 10 days following the onset of menstration |
| Classify the following tissues in order according to increasing radiosensitivity | muscle cells, liver cells, intestinal crypt cells |
| How does filtration affect the primary beam? | .It increases the average energy of the primary beam |
| Somatic effects of radiation refer to effects that are manifested | during the life of the exposed individual |
| The time it takes for a radioactive material to have ½ of it atoms disintegrate is known as what? | half-life |
| Which of the following would be considered natural background radiation? | cosmic rays, alpha particles |
| Which of the following is the unit of exposure dose of gamma or x-rays? | coulomb per kilogram |
| Which of the following describes an alpha particle? | 2 protons, 2 neutrons |
| Approximately how many millisieverts(rem) per film will a female receive to her gonadal area during an IVP examination? | 2.5 mSv(.25 rem) |
| How many milliroentgen are in one roentgen? | 1000 |
| The nucleolus of a typical cell contains which of the following? | RNA |
| Which of the following affects the rate of decay of a radioactive material? | Nothing can affect the rate of decay |
| Which of the following describes a Beta particle? | high speed electron |
| What type of radiation will produce the greatest amount of biologic damage in human tissue? | high linear energy transfer (LET) |
| When using mobile radiographic equipment, the source-to-skin distance cannot be less than what? | 12” |
| Which of the following types of beam restricting devices is considered the best at reducing patient exposure? | extension cylinder |
| To prevent leakage radiation from exposing the patient, an x-ray tube must have how much protective lead? | 1.5mm |
| What is the main purpose of a filter in diagnostic radiology | to remove low energy photons |
| Long-term effects of radiation include (3) | formation of cataracts, cancer, genetic effects |
| . What is the dose equivalent limit to the fetus of a pregnant radiologic technologist? | 5mSv (.5rem) |
| The lead equivalency for a pair of protective gloves must be at least how much? | 0.25mm |
| What percentage of the primary exposure to the patient will reach a radiographer standing 1 meter away? | 0.10% |
| The “Direct Hit” theory of cell irradiation can be described by which of the following statements? | the DNA molecule is struck |
| What is the name of the stage of cell division that is commonly referred to as the resting stage? | interphase |
| Which of the following types of blood cell are the most sensitive to radiation? | lymphocytes |
| What is the molecule called that has one or more unpaired electrons and is unusually chemically reactive? | free radicals |
| If a human is exposed to radiation levels in the 100 to 200 R range, which of the follwing is expected? | complete recovery in 90 days |
| What is the most radiosensitive are of the eye? | lens |
| Which of the following statements is true regarding the biologic effects of ionizing radiation? | the body has the ability to repair most damage |
| When radiation exposure causes hemopoietic death, what is the main reason why the person died? | immune system is destroyed |
| A “Caution Radiation Area” sign must be visible in areas where the exposure rate exceeds which of these? | 5 mR/hr |
| Which of the following determines what the final effects from radiation will be? | type of radiation, type of tissue, energy of radiation |
| Which of the following topics is covered in NCRP Report No. 102? | equipment design and use, personnel monitoring, radiation survey procedures |
| Personnel monitoring shall be performed if there is a possibility of exceeding how many rem per year? | 0.50 rem |
| Which of the following publications contains the regulations for using x-rays up to 50 MeV? | NCRP Report No. 102 |
| When glass is present in a wall of a radiographic room that has the potential to be struck with the primary x-ray beam, what is the minimum requirement of radiation shielding for the glass? | 1/16” of lead equivalent shielding |
| The biologic effects of radiation that increase in severity in proportion to the dose are categorized as: | deterministic effects |
| It is assumed that there is no threshold dose of radiation, this means that: | C.Even small amounts of radiation are potentially harmful |
| Which of the following is a process of generating x-rays by involving an interaction of electrons with the nucleus of the atoms of tungsten; emitting at all energies from just above 0 to the maximum set energy? | bremsstrahlung radiation |
| Primary radiation barrier must be at least how high? | 7ft |
| In the production of Brems radiation, the incident electron: | it is deflected with resulting energy loss |
| Which of the following causes excitation rather than ionization? | coherent scatter |
| Which of the following systems is the most radiosensitive? | hematopoietic |
| The primary function of filtration is to: | reduce patient skin dose |
| The x-ray interaction with matter that is responsible for the majority of scattered radiation reaching the film is: | compton scattering |
| To be in compliance w/ radiation safety standards, the fluoro switch must: | be the dead man switch |
| When using mobile radiographic equipment, the length of the exposure switch cord should be at least: | 6ft |
| What is the annual dose limit as recommended by the NCRP for the lower extremities of occupational personnel? | 500 mSv (50,000mrem) |
| The type of dose-response curve used to predict genetic effects is the: | linear nonthreshold |
| The total amount of energy absorbed by a specific mass of tissue is called what? | integral dose |
| A backup timer for the automatic exposure control serves to: | protect the patient from over exposure and protect the xray tube from excessive heat |
| Patient dose can be decreased by using: | high speed film and screen combination |
| The quality assurance term used to describe consistency in exposure with adjacent mA stations and exposure times adjusted to produce the same mAs is : | linearity |
| What is meant by saying x-rays are heterogeneous? | they have many different wavelengths |
| The genetically significant dose is increasing as a result of which of the following? | defensive medicine, increased diagnostic efficacy |
| Gene pairs are also known as: | alleles |
| If a radiation dose is split into smaller amounts over time, it is referred to as what kind of dose? | fractionated |
| Cancer cells differ from normal cells in what way? | an increased amount of chromatin and an increased ratio of nuclear material to cytoplasm |
| Which of the following graphs would best describe a response to radiation exposure in direct proportion to that exposure? | linear |
| A non-threshold dose-effect relationship can be described as: | a response to the dosage regardless of how large or small the dosage is |
| Which of the following best describes a nonstochastic effect? | dose-response relationship that demonstrates a threshold at which the severity rather than the probability of the response will occur |
| To experience a central nervous system syndrome due to radiation, the exposed individual would need to receive a dosage of: | 2000 to 5000 rad |
| A high-frequency generator will minimize patient exposure doses by providing a: | .More monoenergetic primary beam |
| The ALARA concept follows which dose-response relationship? | Linear-nonthreshold |
| A field survey instrument that determines exposure rates based upon the quantity of ion pairs detected by the unit is a : | Ionization chamber |
| Characteristic radiation is produced at higher energies because: | the material used to construct the anode has a high atomic number |
| For a photon to interact with the nucleus of an atom and cause the release of a nuclear fragment, the incident photon must be at which energy level? | 10MeV |
| so this a different test......... i was wondering if she sent me test | 3 for registry review . Whenever we go over the material for test |
| unnecessary exposure to ionizing radiation is an unacceptable risk with no benefit when referring to the : | general public |
| HVL refers to: | half-value layer |
| tubes operating between 50-70 kvp should have at least a ________ Al equivalent of filtration? | 1.5 |
| tubes operating above kvp should have at least a ________ Al equivalent of filtration? | 2.5 |
| the xray field must be aligned to the center of the image receptor to within _% of the SID? | 2% |
| A timer device must be available that will signal the fluoroscopist when ______ minutes has been reached? | 5 |
| is responsible for monitoring workplaces, especially in commercial industry: | OSHA |
| Is considered primary protective barriers except: | the ceiling |
| where the radiation level could result in an individual receiving more than 150 mrem in one hour | high radiation area |
| the most common and cheaping personal monitoring device: | film badge |
| the wall shall be at least _____ ft high | 7ft |
| the proper clothing consists of a leaded apron not less than ____mm of lead equilvalent shielding | 0.5mm |
| gonadal shielding should not be less than: | .25mm of lead equivalent |
| the fetal badge should be worn: | under the lead apron |
| the organization that regulates the design and manufacture of xray equipment: | FDA |
| exposure from a fluoroscopic unit that is not directed to the image receptor must be less than ____ mR/hour at 10 cm | 2 |
| in no case may a mobile C-arm be operated at less than _____ cm cource to skin distance | 20 |
| any area of the body struck by the beam must be covered with _mm of lead equivalent | 0.5 |
| the maximum dose allowed to the fetus/embryo of the radaition worker is ____rem | 0.50 rem |
| three basic principles that guide radiation protection are: | time, distance, shielding |
| time and exposure are directly or indirectly proportional? | are directly proportional |
| most of a radiogrpahers dose comes from | compton scatter |
| at a distance of 1 meter from the scattering object, the intensity of radiation in fluoro decreases to: | 0.10% |
| if distance is cut in half what happens to intensity | intensity will increase by a factor of 4 |
| as distance increases what happens to intensity | intensity decreases |
| there is an increase rate in death if radiation is recieved during the: | 1st gestational period |
| congential anomalies are more likely to occur during: | 2-8 weeks |
| a moving bucky absorbs _____scatter than a stationary grid: | 10-15% more |
| it is preferred to do cranial exams: | PA rather than Ap |
| a lead apron covers about what % of the active bone marrow in the body? | 80% |
| the best means of minimizing exposure during fluoro are? | increasing kvp, increasing distance, standing behind the operator |
| each scattering event reduces radiation intensity by what factor? | 1000 |
| the second highest intensity to the fluoroscopist is at the level of the : | thyroid |
| the most effective means of reducing exposure is: | distance |
| what two techniques produce the same dose? | 36 mas and 90 kvp, 75 mas and 76 kvp |
| the reciprocity law deals with: | mA and time |
| total filtration | a sum of that added to the tube and inherent filtration of the tube itself |
| if you increase mAs, exposure and density increase directly or indirectly proportionately | exposure and density increase in direct pro. |
| if you increase KvP, exposure and density increases directly or indirectly proportionately | exposure and density increase not in direct pro. |
| trough and wedge filter are examples of : | compensating filtration |
| what is not used to help with beam attenuation: | filters |
| when you increase the total filtration: | radiation exposure is decreased and image quality is maintained |
| grids are used when the part thickness exceeds: | 10-13 cm |
| adding a grid will produce a : | shorter scale contrast |
| using an air gap will: | cause a decrease in exposure |
| the fact that increasing the SOD will decrease exposure is an example of the: | inverse square law |
| a _____% reduction in the radiation exposure to the lens of the eye is possible when using PA instead of PA: | 95% |
| increasing in film speed: | decrease radiation exposure and increase the image detail |
| collimation and other forms of beam limitation will: | decrease radiation exposure and increase image quality |
| is the organization that provides state licensing of radiographers and voluntary certification to ensure that patients are provided with competent practitoners able to protect the patient from excessive radiation: | ARRT |
| Are in charge of making sure that school programs are accredited: | JRCERT |
| the amount of attenuatiion needed to reduce the intensity to 1/10 of its orginal value | TVL |
| the annual occupational dose for a 35 year old under the NCRP IS: | 5 REM/YR |
| According to MPD, the cumulative whole body dose for a 45 year old should be: | 135 rem |
| dose equivalence formula: | 10 msV xN |
| A Lead barrier is preferred because: | high density, high atomic number, and high absorption |
| if all other factors remain constant radiaton dose is related to xray beam on time: | directly |
| area where 60 mrem can be reached: | radiation area |
| when time is doubled what happens to intensity and pt dose | the intensity of radiation and patient dose is also doubled |
| increasing the distance from 20-30 in will: | decrease intensity by a factor or 4/9 |
| leaded gloves should be how thick | .25mm pb/eq |
| examples of inherent filtration are: | glass envelopes and cooling oil surrounding the tube |
| grids require you to do what to technique | increase in techn. and increase in patient dose |
| the function of the grids is to: | improve contrast and absorb scatter |
| the most versatile type of xray beam limitation device is : | the light localizing variable aperture rectangular collimator |
| are reasons for using beam restricting devices: (3) | reduce scatter, reduce patient exposure, increase contrast |
| beam filtration affects the primary beam by: | making it more homogenous |
| the 23 pairs of somatic or nonreproductive cells are called what? | 2n or diploid number |
| what are the gametes or reproductive cells called? | haploid |
| what is mitosis? | type of cell division of somatic cells wherein each daughter cell contains the same |
| the primary mechanism for indirect action is the _______(breakdown by radiation) or water | radiolysis |
| what type of dose response curve is used for high dose levels associated with radiation therapy? | sigmoid threshold |
| what type of dose response curve is used for low to moderate dose levels? | linear nonthreshold |
| besides leukemia, breast cancer and genetic damage are assumed to follow what type of curve? | linear nonthreshold |
| what are the characteristics of a sigmoid dose-response curve? | threshold, partial recovery, dose rate effect, plateau and turning downward at the highest doses, and curve exhibits nonstochastic behavior or the certainty effect |
| _________ means random in nature | stochastic |
| when a change is made from a 200 speed film/screen system to a 400 speed film/speed system, radiation exposure to the patient is: | decreased by approx. 50% |
| a radiographic grid is recommended to be used when the part measures greater than: | 10cm |
| if distance from the source is increased from 1.5 to 2ft, and original exposure was 5mrem, the new exposure will be what? | 2.8 mrem/min |
| Which is a tenet of the ALARA concept? | Radiographer’s exposure should be as low as reasonably possible. |
| Monthly EqD to embryo-fetus? | 0.5 mSv (0.05 rem) |
| Radiation sources generated in diagnostic x-ray room? | Primary, scatter, leakage |
| During C-arm fluoroscopy, the exposure rate caused by scatter near the entrance surface of the patient (the x-ray tube side)____________________the exposure rate caused by scatter near the exit surface of the patient (the image intensifier side). | Exceeds |
| What contributes to high-level control interventional procedures dose reductions? | High quality, low dose fluoroscopy mode and pulsed radiation mode; collimation and filtration; roadmapping, time interval differences, and last-image-hold features. |
| Peak energy of diagnostic x-ray beam is 130 kVp, the primary protective barrier generally should consist of at least ____ lead and extend ______upward from the floor of the x-ray room when tube is 5-7 feet from wall in question. | 1/16” lead; 7ft. |
| Which of the following radiation sources is the control booth barrier not intended to intercept? | primary radiation |
| Protective shielding for an uncontrolled area must ensure maximal EqD for that areais no greater than ____. | 20 microsievert 1rem |
| Beam direction factor is also known as what? | use factor |
| When distance from source of radiation and a measured point is quadrupled intensities…. | decrease by a factor of 16 at new distance |
| the radiographer stands 1 m from tube is subject to an exposure of 4 mR/hr, what will the exposure rate be if the radiographer moves to 2 m? | 1 mR/hr |
| If the radiographer moves closer to a source of radiation, radiation exposure to the radiographer…. | increases significantly |
| The source to skin distance shall be limited to not less than _____on mobile fluoroscopes. | 30cm |
| Intensity of x-ray photon affected after each time it scatters? | intensity decreases 1000 times |
| Mobile units and fluoroscopic equivalency require a minimum of ____mm Al Eq total permanent filtration. | 2.5mm Al eq |
| How many HVL’s are needed to reduce the beam from 800 mR to 100 mR? | 3 |
| How many HVL’s needed to reduce the beam from 100 mR to below 6.25mR? | 5 |
| What is the equivalent unit during entire pregnancy for a radiation worker? | 5mSv 500rem |
| Which of the following does not actively reflect Equivalent dose limits? | the units represent the average exposure of personnel exposed to ionizing radiation |
| The best location for control panel exposure switch stationary on control panel or short card so that it can only be used by from within | control panel |
| Secondary barriers are given a use factor of one because? | scatter of radiation and leakage radiation is always present when the xray tube is energized |
| Minimizing exposure during fluoroscopy: | protective drapes between operator and side of patient and use bucky slot cover and cumulative timer rotate personnel distribute dose between people |
| In mobile equipment, the radiographer should stand in relation to the patient and primary beam? | at right angles to the xray beam scattering object |
| The best choice for human restraint during the exam? | an older relative or a friend |
| When is it appropriate to use Bucky slot cover and curtains? | during fluoroscopic procedures |
| In reference to required barrier thickness, the amount of time the x-ray unit actually delivers radiation refers to as: | workload factor |
| What is the dose for caution radiation area is what? | 0.05mSv (0.005rem) in one hr at 30cm from the source or surface it penetrates. |
| The cumulative timer used in fluoroscopy to ensure the radiologic technologist is aware of ? | Total beam on time |
| During imaging procedures, protective eyeglasses are used to do which of the following? | Shield eyes from scatter radiation. |
| When is it the responsibility of female radiographer to tell the hospital that she is pregnant? | As soon as possible after finding out. |
| Leakage radiation is a form of secondary radiation and comes from which of the following? | Leakage of the tube housing. |
| What is the maximal weekly dose limit today for radiation workers? | 1mSv (100rem) |
| What is clear Pb (lead)? | transparent acrylic material with 30% leads by weight. |
| When should lead equivalent gloves do minimum of 0.25mm be worn to protect hands of the radiographer technician? | When the hands might be in x-ray beam. |
| If the original intensity is 10mrem is based on 10 minutes of the exposure, what will exposure be if the time is reduced to 5 minutes? | 5 mrem |
| If the original intensity of 50mrem is based on 15 minutes of exposure, what will exposure be if the time is reduced to 5 minutes? | 16.67mrem |
| The radiographer received 10 mrem of an exposure at one foot. What will they receive at two feet? | 2.5 mrem |
| Because the workforce in radiation jobs is small compared with the general population as a whole, the amount of radiation received by this workforce can be larger than amount received by the general public without altering the: | GSD (genetically significant dose) |
| A cumulative timing device times the x-ray exposure and sounds an audible alarm or temporarily interrupts the exposure after the fluoroscope has been activated for what amount of time? | 5 minutes |
| If the original intensity is 20mrem based on 20 minute of exposure, what will the exposure be if time is reduced to 10 minute? | 10 mrem |
| Based on the inverse square law, as distance increases, intensity: | Decreases. |
| As the amount of filtration increases, patient dose: | Decreases. |
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