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200 Cards in this Set
- Front
- Back
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Biological material irradiated under hypoxic condition is |
Less sensitive than when irradiated under oxygenated conditions |
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According to the National Council on Radiation Protection and Measurements (NCRP), the monthly gestational dose-equivalent limit for embryo/fetus of a pregnant radiographer is |
0.5 mSv |
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A time of 1.5 mins is required for a particular fluoroscopic exam, whose exposure rate is 275 mR/h. What is the approximate radiation exposure for the radiologic staff present in the fluoroscopy room during the examination? |
6.87 mR - The exposure rate for exam taking 60 minutes will be more than and exam taking 3 minutes. |
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Stochastic/probabilistic effects of radiation are those that |
May be described as "all-or-nothing" effects & are late effects. |
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What percentage of public exposure to ionizing radiation is from medical sources? |
50%. |
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Which of the following cell types has the greatest radiosensitivity in the adult human? |
Lymphocytes |
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Guidelines for the use of protective shielding state that gonadal shielding should be used |
If the patient has reasonable reproductive potential & when the gonads are within 5cm of the collimated field |
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The interaction between ionizing radiation and the target molecule that is most likely to occur is |
Indirect effect |
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Sources of natural background radiation include |
1. Radon 2. Internal sources 3. Thoron |
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The unit used to express kinetic energy released in matter is the |
Kerma. |
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Which acute radiation syndromes requires the largest exposure before the associated effects become apparent? |
Central nervous system (CNS) |
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What is the established annual occupational dose equivalent limit for the lens of the eyes? |
150 mSv. - (Or 15 rem) |
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Occupational radiation monitoring is required when it is possible that the individual might receive more than |
One-tenth the annual dose limit |
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Sources of natural background radiation contributing to whole-body radiation dose include |
Terrestrial radionuclides & Internal radionuclides |
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Irradiation of water molecules within the body and their resulting breakdown is termed |
Radiolysis |
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Diagnostic x-radiation may be correctly described as |
Low energy, low LET |
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Which of the following is used to account for the differences in tissue characteristics when determining effectives dose to biologic material? |
Tissue weighting factors (Wt) |
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The x-ray interaction with matter that is responsible for the majority of scattered radiation reaching the image receptor (IR) is |
Compton Scatter |
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The exposure rate to a body 4 ft from a sources of radiation is 16 R/h. What distance from the source would be necessary to decrease the exposure to 6 R/h? |
7 ft |
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Protective devices such as lead aprons function to protect the user from |
Scattered radiation |
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Late radiation-induced somatic effects include |
1. Thyroid cancers 2. Cataractogensis 3. Genetic mutations |
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Each time an x-ray beam scatters, its intensity at 1 m from the scattering object is what fraction of its original intensity? |
1/1,000 |
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The law of Bergonie and Tribondeau states that cells are moe radiosensitive if they are |
Highly proliferative & immature |
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A thermoluminescent dosimetry system would use which of the following crystals? |
Lithium fluoride |
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Sources of secondary radiation include |
Leakage radiation & Scattered radiation |
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All of the following have an effect on patient dose except |
Focal spot size |
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The photoelectric effect is more likely to occur with |
Absorbers having a high Z number & Positive contrast media |
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An increase in total filtration of the x-ray beam will increase |
Beam HVL |
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In radiation protection, the product of absorbed dose, tissue weighting factor, and radiation weighting factor is used to determine |
EfD |
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Which of the following is recommended for the pregnant radiographer? |
Wear a second dosimeter under the lead apron |
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The annual dose limit for medical imaging personnel includes radiation from |
Occupational exposure |
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Which of the following anomalies is possible if an exposure dose of 40 rad (400 mGy) were delivered to a pregnant uterus in the third week of pregnancy? |
Organ anomaly |
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If a quantity of ionizing 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 |
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Moving the image intensifier closer to the patient during fluoroscopy |
1. Decrease patient dose 2. Improves image quality 3. Decreases the SID |
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Which of the following is composed of nondividing, differentiated cells? |
Neurons and neuroglia |
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How does filtration affect the primary beam? |
It increases the average energy of the primary beam |
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What is the minimum lead requirement for lead aprons, according to the NCRP? |
0.50 mm Pb equivalent |
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The most radiosensitive portion of the GI tract is the |
Small bowel |
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Immature cells are referred to as |
Undifferentiated cells & Stem cells |
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What is the term used to describe x-ray beam photon interaction with matter and the transference of part of the photon's energy to matter? |
Scattering |
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Advantages of anatomic compression during imaging include |
1. Decreased patient dose 2. Improved image resolution 3. Improved spatial resolution |
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To be in compliance with radiation safety standards, the fluoroscopy exposure switch must |
Be the "dead man" type |
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Any wall that the useful x-ray beam can be directed toward is called a |
Primary barrier |
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The annual dose limit for occupationally exposed individuals is valid for |
1. Beta 2. x- 3. gamma radiations |
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The interaction between x-ray photons and matter shown is associated with |
An inner shell electron & Photoelectric effect. |
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Patient dose increases as fluoroscopic |
FOV decreases |
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Types of gonadal shielding include which of the following? |
1.Flat contact 2. Shaped contact 3. Shadow |
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LET is best defined as |
A method of expressing radiation quality & A measure of the rate at which radiation energy is transferred to soft tissue |
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For 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 |
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What unit of measure is used to express ionizing radiation dose to biological material? |
Rem (Sv). - Radiation-equivalent |
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The skin response to radiation exposure that appears as hair loss is known as |
Epilation |
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Examples of late effects of ionizing radiation on humans include |
1. Leukemia 2. Local tissue damage 3. Malignant disease |
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The reduction in the intensity of an x-ray beam as it passes through material is termed |
Attenuation. |
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Which type of dose-response relationship represents radiation-induced leukemia and genetic effects? |
Linear, nonthreshold |
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A dose of 25 rad to the fetus during the seventh or eighth week of pregnancy is likely to cause which of the following? |
Neurologic anomalies |
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Late effects of radiation, whose incidence is dose related and for which there is no threshold dose, are referred to as |
Stochastic/probabilistic |
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What is used to illustrate the relationship between exposure to ionizing radiation and possible resultant biologic responses? |
Dose-response curve |
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Classify the following tissues in order of increasing radiosensitivity: |
1. Muscle cells 2. Liver cells 3. Intestinal crypt cells |
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The largest amount of diagnostic x-ray absorption is most likely to occur in which of the following tissues? |
Bone |
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According to NCRP regulations, leakage radiation from the x-ray tube must not exceed |
100 mR/h (1.0 mGy/hr) |
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Patient dose during fluoroscopy is affected by the |
1. Distance between the patient and the input phosphor 2. Amount of magnification 3. Tissue density |
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Which of the following statements is true with respect to radiation safety in fluoroscopy? |
1. Tabletop radiation intensity must not exceed 2.1 R/min/mA 2. Tabletop radiation intensity must not exceed 10 R/min 3. In high-level fluoroscopy, tabletop intensity up to 2- R/min is permitted. |
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The symbols 130/56 Ba and 138/56 Ba are examples of which of the following? |
Isotopes |
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Which of the following accounts for an x-ray beam heterogeneity? |
1. Incident electrons interacting with several layers of tungsten target atoms 2. Energy differences among incident electrons 3. Electrons moving to fill different shell vacancies |
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Which of the following factors will affect both the quality and the quantity of the primary beam? |
Half-value layer (HVL) & Kilovolts (kV) |
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Which of the following contributes most to occupational exposure? |
Compton scatter |
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Primary radiation barriers usually require which thickness of shielding? |
1/16-inch lead |
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Which of the following groups of technical factors will deliver the least patient dose? |
600 mA, 30 ms, 90 kVp |
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For radiographic examinations of the skull, it is generally preferred that the skull be examined in the |
PA projection |
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According to the NCRP, the annual occupational dose-equivalent limit (50 rem) to the thyroid, skin and extremities is |
500 mSv. |
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What is the relationship between LET and RBE? |
As LET increase, RBE increases |
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Which of the dose-response curves shown in a linear threshold response to radiation exposure? |
Dose-response curve B |
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The NCRP recommends an annual effective occupational dose-equivalent limit of |
5 rem (50 mSv). |
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Which of the following formulas is a representation of the inverse-square law of radiation used to determine x-ray intensity at different distances? |
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An increase of 1.0-mm added aluminum filtration of the x-ray beam would have which of the following effects? |
Increase in average energy of the beam |
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Aluminum filtration has its greatest effect on |
Low-energy x-ray photons |
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The amount of time that x-rays are being produced and directed toward a particular wall is referred to as |
Use factor |
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The operation of personnel radiation monitoring devices can depend on which of the following? |
1. Ionization 2. Luminescence 3. Thermoluminescence |
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Which of the following results from restriction of the x-ray beam? |
Less scattered radiation production & Less patient hazard |
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How will x-ray photon intensity be affected if the source-to-image distance (SID) is doubled? |
Its intensity decreases four times |
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Early symptoms of acute radiation syndrome include |
1.Leukopenia 2. Nausea 3. Vomiting |
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Referring to the nomogram, what is the approximate patient ESE from an AP projection of the abdomen made at 105 cm using 70 kVp, 300 mA, 200 ms, and 2.5 mm Al total filtration? |
288 mR. |
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The unit of measurement used to express occupational exposure is the |
rem (Sv) |
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Which of the following refers to a regular program of evaluation that ensures the proper functioning of x-ray equipment, thereby protecting both radiation workers and patients? |
Quality control |
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The Bucky slot cover is in place to protect the |
Fluoroscopes & technologists |
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Which type of personnel radiation monitor can provide an immediate reading? |
Ionization chamber |
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Which of the following terms is correctly used to describe x-ray beam quality? |
HVL |
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The most effective type of shield for anterior and lateral male gonadal protection during fluoroscopy is |
Shaped contact (contour) |
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Isotopes are atoms that have the same |
Atomic number but a different mass number |
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If the ESE for a particular exposure is 25 mrad, what will be the intensity of the scattered beam perpendicular to and 1 m from the patient? |
0.025 mrad |
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The likelihood of adverse radiation effects to any radiographer whose dose is kept below the recommended guideline is |
Very remote |
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Factors that contribute to the amount of scattered radiation produced include |
Radiation quality & Field size |
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The SSD in mobile fluoroscopy must be |
A minimum of 12 in |
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The automatic exposure device that is located immediately under the x-ray table is the |
Ionization chamber |
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According to the NCRP, the annual occupational whole-body dose-equivalent limit is |
50 mSv |
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It is necessary to question a female patient of child bearing age regarding her |
Date of last menstrual period & Possibility of being pregnant |
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Which of the dose-respone curves seen represents possible genetic effects of ionizing radiation? |
Dose-response curve A. |
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What is the effect on RBE as LET increases? |
As LET increases, RBE increases |
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Which of the following would most likely result in the greatest skin dose? |
Short SID. |
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Which of the following radiation-included conditions is most likely to have the longest latent period? |
Leukemia |
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Which of the following ionizing radiations is described as having an RBE of 1.0? |
Diagnostic x-rays. |
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If an individual receives 50 mR while standing 4 ft from a source of radiation for 2 mins, which of the following options will most effectively reduce his or her radiation exposure to that source of radiation? |
Standing 8ft from the source for 2 mins. |
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An optically stimulated luminescence dosimeter contains which of the following detectors? |
Aluminum oxide |
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How do fractionation and protraction affect radiation dose effects? |
1. They reduce the effect of radiation exposure 2. They permit cellular repair 3. They allow tissue recovery |
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The photoelectric effect is an interaction between an x-ray photon and |
An inner-shell electron |
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Filters used in radiographic x-ray tube generally are composed of |
Aluminum |
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All of the following function to reduce patient dose except |
A high-speed grid |
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In the production of Bremsstrahlung radiation |
The incident electron is deflected, with resulting energy loss |
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All of the following radiation-exposure responses exhibit a nonlinear threshold dose-response relationship except |
Leukemia |
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Which of the following is often used to express exposure in air? |
Rad (Gy). |
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The purpose of filters in a film badge is |
To measure radiation radiation quality. |
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How many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 15% of its original value? |
3. First HVL = reduced by 50% Second HVL = reduced by 25% Third HVL = reduced by 12.5% Fourth HVL = reduced by 6.25% |
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Which of the following has an effect on the amount and type of radiation-induced tissue damage? |
1. Quality of radiation 2. Type of tissue being irradiated 3. Fractionation |
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Radiation dose to personnel is reduced by which of the following exposure control cord guidelines? |
Exposure cords on fixed equipment must be very short & Exposure cords on mobile equipment should be fairly long. |
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Primary radiation barriers must be at least how high? |
7ft. |
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Which of the following body parts are included in a whole-body dose? |
Gonads & Blood-forming organs. |
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Which of the following projections would deliver the largest thyroid dose? |
AP skull. |
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Which of the following personnel monitoring devices used in diagnostic radiography is considered to be the most sensitive and accurate? |
OSL dosimeter. |
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Irradiation of macromolecules in vitro can result in |
1. Cleaved chromosome 2. Cross-linking 3. Mutation |
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Which of the following radiation situations is potentially the most harmful? |
A large dose to the whole body all at one time |
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How much protection is provided from 100 kVp x-ray beam when using a 0.50-mm lead equivalent apron? |
75%. |
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Occupational radiation monitoring is required when it is likely that an individual will receive more than what fraction of the annual dose-limit? |
1/10. |
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The interaction illustrated |
Can pose a safety hazard to personnel Can have a negative impact on image quality. |
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Biologic material is least sensitive to irradiation under which of the following conditions? |
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Which of the following cells are the most radiosensitive? |
Erythroblasts |
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Which of the following statements regarding the pregnant radiographer is true? |
1. She should declare her pregnancy to her supervisor 2. She should be assigned a second personnel monitor 3. Radiation history should be reviewed |
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Effects of deoxyribonucleic acid (DNA) irradiation include |
1. Mitotic delay 2. Reproductive death 3. Chromosome breakage |
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Which of the following contributes most to patient dose? |
The photoelectric effect |
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Which of the following statements is true with respect to the dose-response curve shown |
The quantity of radiation is directly used to the dose received & A minimum amount of radiation is required for manifestation of effects |
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The classifications of acute radiation syndrome include all the following except |
Neonatal |
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In the production of characteristic radiation at the tungsten target, the incident electron |
Ejects an inner-shell tungsten electron |
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Which of the following defines the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals? |
Genetically significant dose |
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If an exposure dose of 50 mR/h is delivered from a distance of 3 ft, what would be the dose delivered after 20 mins at a distance of 5 ft from the source? |
6 mR |
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The term effective dose refers to |
Whole-body dose |
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Which of the following are possible long-term somatic effects of radiation exposure? |
Cataractogenesis & Embryologic effects |
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The operation of personal radiation monitoring can be based on stimulated luminescence. Which of the following personal radiation monitors function in that manner? |
OSL dosimeter & TLD |
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If a patient received 1,400 mrad during a 7 min fluoroscopic exam, what was the dose rate? |
0.2 rad/min |
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What is used to account for the differences in tissue sensitivity to ionizing radiation when determining effective dose E? |
Tissue weighting factors (Wt) |
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Which interaction between ionizing radiation and the target molecule involves formation of a free radical? |
Indirect effect |
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The single most important scattering object in both radiography and fluoroscopy is the |
Patient |
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All the following statements regarding TLDs are true except |
After x-ray exposure TLDs emit heat in response to stimulation by light |
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A student radiographer who is under 18 years old must not receive an annual occupational dose of greater than |
0.1 rem (1 mSv) |
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Sources of medical radiation exposure include |
Computed tomography |
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Which of the following is likely to improve image quality and decrease patient dose? |
Beam restriction |
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Types of secondary radiation barriers include |
1. The control booth 2. Lead aprons 3. x-ray tube housing |
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Which of the following radiation protection concepts/measures apply to mobile radiography? |
1. The radiographer should be atleast 6ft from patient and x-ray tube during exposure 2. The least amount of scattered radiation is perpendicular to the scattering object 3. At least one lead apron should be assigned to each mobile unit |
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Types of structural damage to a DNA molecule by ionizing radiation include which of the following? |
Single-side-rail scission Double-side-rail scissionCross-linking. - |
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Which of the following can be an effective means of reducing radiation exposure? |
1. Barriers 2. Distance 3. Time |
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The effects of radiation on biologic material depend on several factors. If a larger quantity of radiation is delivered to a body over a short period of time, the effect |
Will be greater than if it were delivered in increments |
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Somatic effects of radiation refer to effects that are manifested |
During the life of the exposed individual |
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What minimum total amount of filtration (inherent plus added) is required in x-ray equipment operated above 70 kVp? |
2.5-mm Al equivalent |
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The dose of radiation that will cause a noticeable skin reaction is referred to as the |
SED |
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What is the intensity of scattered radiation perpendicular to and 1 m from a patient compared with the useful beam at the patients surface? |
0.1% |
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Some patients, such as infants and children, are unable to maintain the necessary radiographic position without assistance. If mechanical restraining devices cannot be used, who of the following should be first choice to help immobilize the patient? |
Patient's father |
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A controlled area is defined as one |
1. That is occupied by people trained in radiation safety, 2. That is occupied by people who wear radiation monitors 3. Whose occupancy factor is 1 |
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Which of the following terms refers to the period between conception and birth? |
Gestation |
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Somatic effects resulting from radiation exposure can |
Have possible consequences on the exposed individual & cause temporary infertility |
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If the image intensifier is moved farther from the patient |
SID increases |
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In which type of monitoring device do photons release electrons by their interaction with air? |
Pocket dosimeter |
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The advantages of beam restriction include which of the following? |
Less scattered radiation is produced & Less biologic material is irradiated |
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The person responsible for ascertaining that all radiation guidelines are adhered to and that personnel understand and employ radiation safety measures is the |
Radiation safety officer |
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The dose-response curve that appears to be valid for genetic and some somatic effects is the |
Linear & Non threshold |
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Which of the following statements regarding the human gonadal cells is true? |
The female oogonia reproduce only during fetal life & the male spermatogonia reproduce continuously |
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Which milliamperes (mA) increased to maintain output intensity, how is the ESE affected as the source-to-skin (SSD) is increased? |
The ESE decreases |
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The primary function of filtration is to reduce |
Patient skin dose |
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Which of the following factors can effect the amount or the nature of radiation damage to biologic tissue? |
1. Radiation quality 2. Absorbed dose 3. Size of irradiated area |
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Examples of stochastic/probabilistic effects of radiation exposure include |
1. Radiation-induced malignancy 2. Genetic effects 3. Leukemia. |
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Which of the following tissues are considered to be particularly radiosensitive? |
Intestinal mucous membrane |
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Which of the following groups of technical factors will deliver the least amount of exposure to the patient? |
400 mA, 0.25 second, 100 kVp |
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If the exposure rate to an individual standing 4.0 m from a source of radiation is 10 mR/h, what will be the dose received after 20 mins at a distance of 6 m from the source? |
1.48 mR |
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Which of the following projections is most likely to deliver the largest dose to the ovaries? |
AP lumbar spine, 14X17 inch Ir, 80 kVp |
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Under what circumstances might a radiographer be required to wear two dosimeters? |
During pregnancy & While performing vascular procedures |
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What quantity of radiation exposure to the reproductive organs is required to causes temporary infertility? |
200 rad |
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Which of the following personnel radiation monitors will provide an immediate reading? |
Pocket dosimeter |
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The tabletop exposure rate during fluoroscopy shall not exceed |
10 R/min |
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Which of the dose-response curves is representative of radiation-induced skin erythema? |
Dose-response curve C |
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If the exposure rate at 3 ft from the fluoroscopic table is 40 mR/h, what will be the exposure rate for 30 mins at a distance of 5 ft from the table? |
7 mR |
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Lead aprons are worn during fluoroscopy to protect the radiographer from exposure to radiation from |
Comptons scatter |
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Radiation that passes through the tube housing in direction other than that of the useful beam is termed |
Leakage radiation |
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The presence of ionizing radiation may be detected in which of the following ways? |
1. Ionizing effect on air 2. Photographic effect on film emulsion 3. Fluorescent effect on certain crystals |
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Possible responses to irradiation in utero include |
1. Spontaneous abortion 2. Congenital anomalies 3. Childhood malignancies |
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What should be the radiographer's main objective regarding personal radiation safety? |
To keep personal exposure as far below dose limit as possible |
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Referring to nomogram, what is the approximate patient ESE from a particular propjection made 105cm using 110 kVp, 300 mA, 5 ms, 2.5 mm Al total filtration? |
18 mR |
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If the exposure rate to a body standing 7ft from a radiation source is 140 mR/h, what will be the dose to that body at a distance of 8ft from the source in 30 mins? |
53.6 mR |
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Which of the following types of radiation are considered electromagnetic? |
X-ray & Gamma |
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Which of the following features of fluoroscopic equipment are designed especially to eliminate unnecessary radiation exposure to the patient and/or personnel? |
1. Bucky slot cover 2. Exposure switch/foot pedal 3. Cumulative exposure timer |
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Radiation output from a diagnostic x-ray tube is measured in which of the following units of measurements? |
Roentgen |
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Which of the following are considered especially radiosensitive tissues? |
1. Bone marrow 2. Intestinal crypt cells 3. Erythroblast |
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Which of the following safeguards is taken to prevent inadvertent irradiation in early pregnancy? |
1. Patient postings 2. Patient questionnaire 3. Elective booking |
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The interaction between x-ray photons and tissue that is responsible for radiographic contrast but that also contributes significantly to patient dose is |
The photoelectric effect |
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Which of the following are acceptable ways to monitor the radiation exposure of those who are occupationally employed? |
TLD & OSL dosimeter |
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The genetic dose of radiation borne by each member of the reproductive population is called the |
Genetically significant dose |
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According to the NCRP, the pregnant radiographer's gestational dose-equavilent limit for a 1 month period is |
0.5 mSv |
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To within what percentage of the SID must the collimator light and actual irradiated area be accurate? |
2% |
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The correct way to check for cracks in lead aprons is |
To fluoroscopic them once a year |
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The target theory applies to |
DNA molecules |
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Which of the following are features of fluoroscopic equipment designed especially to eliminate unnecessary radiation to the patient/personnel? |
1. Protective curtain 2. Filtration 3. Collimation |
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Which of the following have been identified as sources of radon exposure? |
Indoors in houses Smoking cigarettes |
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The skin response to radiation exposure, which appears as reddening of the irradiated skin area, is known as |
Erythema |
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The biologic effect on an individual depends on which of the following? |
1. Type of tissue interactions 2. Amount of interactions 3. Biologic differences |
