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RAD201_week 8-12
| Question | Answer |
|---|---|
| Current federal standards limit entrance skin exposure rates of general-purpose intensified fluoroscopic units with maximum technique factors engaged to a maximum of ________________, as measured at the tabletop using an average phantom, with the image in | 88 mGya/min |
| When using digital fluoroscopy systems, making use of the last image hold feature can | be an effective dose reduction technique. |
| The control panel, where technical exposure factors are selected and visually displayed for the equipment operator, must be located | behind a suitable protective barrier that has a radiation-absorbent window that permits observation of the patient during any procedure. |
| Which of the following materials is commonly used in the tabletop of a radiographic examination table to make the tabletop as radiolucent as possible so that it will absorb only a minimal amount of radiation, thereby reducing the patient’s radiation dose? | Carbon fiber material |
| During interventional procedures, high-level control fluoroscopy is employed, resulting in a _______________________ or entrance dose rate to the patient to allow the examination of smaller and lower-contrast objects that are not ordinarily discerned duri | higher entrance exposure rate |
| Of the following procedures, which involve extended fluoroscopic time? 1. Biliary drainage 2. Stent and filter placement 3. Urinary or biliary stone removal | All of the options |
| Computed radiography, because of its higher exposure latitude, makes grid use on the pediatric population | less necessary than was previously believed. |
| When a fluoroscopic image is electronically amplified by the use of an image intensification system, which of the following benefits results? 1. Increased image brightness 2. Saving of time for the radiologist 3. Patient dose reduction | All of the options |
| When an exposed computed radiography imaging plate is ready to be processed, an imaging reading unit is used to scan the photostimulable phosphor imaging plate with | a helium-neon laser beam. |
| Digital radiography images can be accessed | at several workstations at the same time, thus making image viewing very convenient for physicians providing patient care. |
| Fluoroscopic devices are capable of subjecting the patient, the equipment operator, and other personnel near the fluoroscopic equipment to substantial doses of ionizing radiation. These devices include 1. C-arm fluoroscopes. 2. fluoroscopes on stationar | All of the options |
| All digital imaging devices are subject to certain artifacts such as 1. aliasing. 2. moirè patterns. 3. contouring. | All of the options |
| When obtaining a dorsoplantar projection of a foot, which of the following types of filters should be used to provide a greater uniform density of the anatomy? | Wedge filter |
| During a fluoroscopic examination, a resettable cumulative timing device measures the x-ray beam-on time and sounds an audible alarm or in some cases temporarily interrupts the exposure after the fluoroscope has been activated for what length of time? | 5 minutes |
| When generator settings are changed from one mA and time combination to another, the most that linearity can vary is | 10% |
| Most fluoroscopic examinations employ a range of _____________ kVp for adult patients, depending on the body area being examined. | 75 to 110 |
| Digital radiography systems offer several advantages over computed radiography. Some of these include 1. lower dose. 2. ease of use. 3. immediate imaging results. 4. manipulation of the image. | All of the options |
| In digital radiography the number of different shades of gray that can be stored in memory and displayed on a computer monitor is termed | grayscale |
| The protective tube housing serves as a shield against _____________________ entering the x-ray tube, thereby preventing electric shock while also facilitating the cooling of the x-ray tube. | The high voltage |
| Luminance is determined by measuring the concentration of light | over a particular field of view. |
| If the luminance of the collimator light source is sufficient, the localizing light beam will be able to satisfactorily outline the margins of the radiographic beam on the area of clinical interest on | patients of all skin pigmentations |
| Total filtration of _______________________ for fixed x-ray units operating above 70 kVp is the regulatory standard. | 2.5-mm aluminum equivalent |
| When performing a mobile radiographic procedure, to reduce the radiation exposure to the patient, the radiographer must use a minimal source-skin distance of at least | 30 cm |
| In standard image intensification fluoroscopy, an x-ray beam half-value-layer (HVL) of 3 to 4.5 mm aluminum is considered acceptable when kVp ranges from | 80 to 100 |
| What is the purpose of radiographic beam filtration? | To reduce exposure to the patient’s skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam |
| Of the following radiologic procedures, which is (are) considered nonessential? 1. A chest x-ray examination automatically scheduled on admission to the hospital 2. Lumbar spine x-ray examination as part of a pre-employment physical 3. Whole-body compu | all of the options |
| In the event that a pregnant patient is inadvertently irradiated | the radiation safety officer or the medical physicist should perform the calculations necessary to determine fetal dose. |
| Neglecting to use standardized technique charts necessitates estimating the technical exposure factors, which may result in 1. poor-quality images. 2. repeat examinations. 3. additional and unnecessary exposure of the patient. | all of the options |
| Which of the following is frequently a problem in diagnostic pediatric radiography? | Patient motion |
| When a properly calibrated automatic exposure control (AEC) is not employed to obtain a uniform selection of technical x-ray exposure factors, well-managed imaging departments? | Make use of standardized technique charts that have been established for each x-ray unit in that facility. |
| After some decades of experience with modern digital x-ray equipment and as a result of improvements in dosimetry estimates of the efficacy of shielding with modern equipment and techniques, professional and scientific societies are | modifying shielding practices in diagnostic radiology to discourage the use of patient gonadal shielding and fetal shielding. |
| ________________ are the sensing devices most often used to measure skin dose directly. | Thermoluminescent dosimeters |
| Reducing the field size to the anatomic features of interest not only reduces patient exposure but also | increases completed image quality by decreasing scatter. |
| Which of the following must always be the first step in protection of the reproductive organs? | Adequate and precise collimation of the radiographic beam to include only the anatomy of interest |
| The reason for discontinuing patient gonadal shielding and fetal shielding in diagnostic radiology is based on research that the use of such shielding may jeopardize the benefits of the radiologic examination because | an incorrectly placed shield within the collimated x-ray beam when an automatic collimator is used, can result in the lead in the shield obscuring anatomic information or interfering with the AEC system. |
| A blotchy radiographic image that results when an insufficient quantity of x-ray photons reaches the image receptor is called | quantum noise, or mottle. |
| Motion controlled by will is classified as voluntary motion. Lack of such control may be attributed to which of the following? 1. The patient’s age 2. Breathing patterns or problems 3. Physical discomfort 4. Fear of the examination 5. Mental instabil | 1, 2, 3, 4, 5 |
| When a pregnant patient must undergo a radiographic procedure, which of the following practices will minimize radiation exposure? | Selecting technical exposure factors that are appropriate for the part of the body to be imaged and precisely collimating the radiographic beam to include only the anatomic area of interest while shielding the lower abdomen and pelvis when this area does |
| Specific area shielding may be selectively used during some x-ray procedures to protect which of the following? 1. Lens of the eye 2. Breast 3. Upper extremities 4. Lower extremities | 1 and 2 |
| According to the American College of Radiology (ACR), abdominal radiologic examinations that have been requested after full consideration of the clinical status of a patient, including the possibility of pregnancy, need | not be postponed or selectively scheduled. |
| According to the U.S. Public Health Service, the genetically significant dose (GSD) for the population of the United States is approximately | 0.20 mSv |
| Analysis of an imaging department’s repeat rate 1. provides valuable information for process improvement. 2. helps minimize patient exposure. 3. improves overall performance of the department | all of the options |
| During a radiographic examination, which of the following combinations of technical exposure factors reduce patient radiation dose? | Higher kVp, lower mAs |
| Which of the following are reasons for unacceptable images? 1. Patient mispositioning 2. Incorrect centering of the radiographic beam 3. Patient motion during the radiographic exposure 4. Incorrect collimation of the radiographic beam | all of the options |
| Which of the following are involuntary motions that cannot be willingly controlled? 1. Chills 2. Tremors 3. Muscle spasms 4. Pain 5. Active withdrawal | all of the options |
| Essentially all diagnostic medical procedures result in fetal exposures ______________, so that _______________ | of less than 0.01 Gy; the risk of abnormality is very small |
| Because multiple bony areas span the entire body, the radiation dose absorbed by the organ called bone marrow | cannot be measured by a direct method; it can only be estimated |
| Studies of groups such as the atomic bomb survivors of Hiroshima have shown that damage to the newborn is unlikely for doses below | 0.2 Gy |
| Which of the following procedures results in the lowest radiation effective dose to the patient? | Dual energy X-ray absorptiometry |
| Any image that must be repeated because of human or mechanical error during the production of the initial image is considered to be a repeat image. What effect does a repeat image have on the radiation dose received by the patient? | The patient’s skin and possibly the gonads, if they were in the included imaged area, receive a double radiation dose. |
| The annual effective dose limit for individual members of the general population not occupationally exposed is ___________ for continuous or frequent exposures from artificial sources other than medical irradiation and natural background and ____________ | 1 mSv; 5 mSv |
| Which part(s) of a diagnostic x-ray unit should not be touched while a radiographic exposure is in progress? | Tube housing, collimator, and high-tension cables |
| Scattered radiation to the lens of the eyes of diagnostic imaging personnel can be substantially reduced by the use of protective eyeglasses fitted with optically clear lenses that contain a minimal lead equivalent protection level of | 0.35 mm |
| The maximum weekly permitted equivalent dose for a controlled area must not exceed | 1 mSv |
| To ensure that the lifetime risk of occupationally exposed persons remains acceptable, an additional recommendation is that the lifetime effective dose in mSv should not exceed | 10 times the occupationally exposed person’s age in years |
| Which of the following are radiation-shielding design considerations? 1. The mean energy of the x-rays that will strike the barrier 2. Whether the barrier is of a primary or secondary nature 3. The workload of the unit 4. The use factor of the unit 5 | all of the options |
| Whenever scattered radiation decreases, the radiographer’s exposure | decreases |
| For primary radiation, what is the term that represents a portion of beam-on time that the x-ray beam is directed at a primary barrier during the week? | Use factor |
| Compared to general diagnostic radiography performed in an x-ray room, imaging personnel receive the highest occupational exposure during which of the following procedures? | all of the options |
| When a radiologic technologist declares her pregnancy to her employer, which of the following is appropriate? | They continue to perform her duties without interruption of employment, provided that she has received radiation safety counseling and follows established radiation safety practices. |
| Occupational exposure of the radiographer can be kept as low as reasonably achievable (ALARA) through individual monitoring and other protective measures and the use of protective devices. Therefore, because exposure from radiation-related jobs will not a | genetically significant dose |
| During which of the following x-ray examinations should a radiographer always wear a thyroid shield? | Fluoroscopy and x-ray special procedures |
| While standing behind the control-booth barrier, a radiographer makes a radiographic exposure. The x-rays scattered from the patient’s body should ______________ | scatter a minimum of 2 times before reaching any area behind the control-booth barrier. |
| Who should determine the exact shielding requirements for a particular imaging facility? | Medical physicist |
| Which of the following x-ray procedures increases the radiographer’s risk of exposure to ionizing radiation compared to general diagnostic radiography performed in an x-ray room? 1. Mobile C-arm fluoroscopy 2. Interventional procedures that use high lev | all of the options |
| If the intensity of the x-ray beam is inversely proportional to the square of the distance from the source, how does the intensity of the x-ray beam change when the distance from the source of radiation and a measurement point is tripled? | It decreases by a factor of 9 at the new distance. |
| When doors to radiographic and fluoroscopic rooms are closed during radiation exposures, a substantial degree of protection is provided for persons in areas adjacent to the room door. This is because in most facilities room doors have attenuation for diag | 0.8 |
| A protective curtain, or sliding panel, with a minimum of 0.25-mm lead equivalent, should normally be positioned between the fluoroscopist and the patient to intercept which of the following types of radiation? | scattered radiation above the tabletop |
| If the peak energy of the x-ray beam is 100 kVp, a protective lead apron must be the equivalent to at least which of the following measures? | 0.25-mm thickness of lead |
| When the time spent in a higher radiation area is reduced or limited, occupational exposure | is also reduced |
| For C-arm devices with similar fields of view, the dose rate to personnel located within a meter of the patient is ____________ the dose rate to personnel from ___________ | comparable to: routine fluoroscopy |
| _____________ is essentially the radiation output weighted time that the unit is actually delivering radiation during the week | Workload |
| Which of the following is another term for use factor (U)? | Beam direction factor |
| Secondary radiation includes 1. leakage radiation. 2. primary radiation. 3. scatter radiation. | 1 and 3 only |
| Which of the following adjustments in technical exposure factors decreases the production of scattered radiation during routine radiographic procedures? | Increase kVp and decrease mAs in compensation |
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jetsetjes