Safety: Radiation Protection Flashcards
117 - In the prodromal stage, the following symptoms can all be signs of acute radiation exposure of the gastrointestinal tract, with the exception of:
A. Diarrhea
B. Asthenia
C. Dysphagia
D. Dyspepsia
B. Asthenia
Severe nausea, vomiting, cramping in the abdomen, and diarrhea are among the digestive symptoms of acute radiation exposure. These symptoms usually appear a few hours following exposure. Generalized weakness and physical and mental exhaustion are the hallmarks of asthenia.
118 - Acute radiation exposure can cause all of the following effects on the central nervous system (CNS), except:
A. Confusion
B. Loss of consciousness
C. Malaise
D. Coma
E. Convulsions
Correct Answer: C. Malaise
The prodromal stage of acute radiation exposure-related central nervous system (CNS) involvement is characterized by intense anxiety and disorientation, severe nausea, vomiting, watery diarrhea, unconsciousness, and burning sensations to the skin. Onset of symptoms occurs only minutes following excessive exposure, and the prodromal stage can span from minutes to hours. The patient may regain some functionality while in the latent stage. Convulsions, unconsciousness, and a return of loose stool are among the symptoms of the manifest disease stage, followed by death within three days of acute radiation exposure.
120 - In comparison to a lower kVp technique, a greater kVp technique will have a(n):
A. Lower entrance skin exposure
B. Increased contrast effect on the radiographic image
C. Lower patient dose
D. Higher entrance skin exposure
A. Lower entrance skin exposure
In comparison to a lower kVp approach, a greater kVp will yield a lower entrance skin exposure because the beam has more penetrating ability and a higher average energy. Compared to single-phase generators, three-phase and high-frequency generators will result in a reduced entrance skin exposure. This is the consequence of the three-phase and high-frequency units producing a beam with a shorter average photon wavelength than single-phase units due to the greater effective voltage or average voltage. The effect that increased kVp levels have on visual contrast is a disadvantage of employing them to reduce patient dosage. An image with a higher kVp will have less contrast.
121 - Regarding automatic exposure control (AEC), all statements are accurate apart from:
A. AEC is also called phototiming
B. The AEC backup timer reduces the possibility that the patient will be overexposed because of incorrect patient positioning
C. By using a backup timer, the patient’s danger of overexposure from incorrect photocell selection is reduced
D. Reduces the requirement for precise patient positioning
E. Intended to keep radiographic densities constant for patients of various body habitus
D. Reduces the requirement for precise patient positioning
Automatic exposure control (AEC), also referred to as phototiming, is aimed at maintaining consistent radiographic densities on radiographs for a range of patients with differing body habitus. Using AEC requires careful consideration of photocell selection and patient positioning. Erroneous photocell selection or patient positioning can lead to overexposure, which is mitigated by the AEC backup timer.
122 - Which beam restriction device works most effectively at a fixed SID?
A. Cone
B. Aperture diaphragm
C. Collimator
D. A and C
E. A and B
E. A and B
Beam limiting devices like cylinders, cones, and aperture diaphragms are designed to operate at a particular SID. Cylinders and cones may be used for radiographic imaging of the paranasal sinus or facial
123 - When the image receptor is inserted in the Bucky tray, which of the following automatically causes the radiation field size to adjust to the image receptor’s size?
A. Cone
B. Collimator
C. Cylinder
D. Positive beam limitation
E. Aperture diaphragm
D. Positive beam limitation
Beam restriction lowers the quantity of tissue exposed to radiation by limiting the primary X-ray beam to a particular region of interest. Positive beam limitation (PBL) is one type of beam restriction that works by automatically expanding the radiation field size to match the size of the image receptor (IR) when it is inserted into the Bucky tray. Other types of beam restriction devices include collimators, cylinders, cones, and an aperture diaphragm.
124 - A manually adjustable beam restricting device is called a:
A. Cone
B. Collimator
C. Cylinder
D. Aperture
Correct Answer: B. Collimator
Beam restriction lowers the quantity of tissue exposed to radiation by limiting the primary X-ray beam to a particular region of interest. Types of beam restriction devices include collimators, cylinders, cones, positive beam limitation, and an aperture diaphragm. A collimator is a manually adjustable beam-restricting device that limits the area exposed to the primary beam.
125 - An adequate alteration to patient positioning in order to limit entrance skin exposure:
A. When lowering exposure to anterior organs is desirable, AP projections are recommended over PA projections
B. Less breast tissue will be exposed in female patients with AP projections of the thoracic spine
C. It is recommended to perform a PA projection of the skull and facial bones in order to reduce exposure to the orbital lens
D. Because they minimize exposure to the thyroid gland, the RPO and LPO positions of the cervical spine are preferable over RAO and LAO positions
C. It is recommended to perform a PA projection of the skull and facial bones in order to reduce exposure to the orbital lens
To reduce exposure by means of appropriate patient positioning, various positioning modifications can be employed. In female patients, breast tissue exposure is minimized with a posteroanterior (PA) thoracic spine projection as opposed to an anteroposterior (AP) projection. If less exposure to anterior organs is required, PA projections are favored over AP projections. There will be less exposure to the orbital lens with a PA projection of the skull and facial bones. Additionally, because they will minimize exposure to the thyroid gland, RAO and LAO positions of the cervical spine are recommended over RPO and LPO views.
126 - How may effective patient communication help to reduce unnecessary radiation exposure?
A. Repeat exposures might be avoided by eliminating patient motion
B. Patient cooperation can decrease the need for repeat exposures
C. A reduction in the need for repeat exposure correlates directly with decreased patient anxiety
D. A and B
E. A, B, and C
Correct Answer: E. A, B, and C
Effective communication between the radiographer and patient can greatly reduce patient anxiety and solidify patient understanding of their role in the imaging procedure. It is possible to reduce the number of repeat radiographs by communicating effectively the importance of patient cooperation and remaining immobile during exposure.
127 - It is the radiographer’s ethical responsibility to reduce patient dose. Pediatric patients require special consideration because their tissue is still developing and vulnerable to radiation. Among these considerations are:
A. Ensuring proper collimation
B. Utilizing appropriate exposure factors for patient size and habitus
C. Evaluating the patient’s cooperation and, if required, enlisting parental assistance
D. Upholding the ALARA principle
E. All of the above
Correct Answer: E. All of the above
Reducing patient dose is the radiographer’s ethical duty. Since pediatric patients’ tissue is still developing and is radiosensitive, this population requires specific attention. A young patient’s cooperation level must be evaluated by the radiographer before beginning a radiographic examination, and if necessary, parental assistance must be requested. The radiographer also must follow the ALARA principle, ensure that collimation is properly utilized, and use exposure parameters that are appropriate for the size and habitus of the patient. Pediatric patients may require limited radiographic studies; the clinical institution establishes protocols based on ACR appropriateness criteria.
128 - Technical factors must be adjusted to coincide with patient body habitus. Which habitus type is associated with a morbidly obese patient?
A. Isosthenic
B. Hypersthenic
C. Asthenic
D. Hyposthenic
B. Hypersthenic
Technical factors must be adjusted to align with the physical characteristics of the patient. Body habitus can be divided into four categories. The terms asthenic, sthenic, hyposthenic, and hypersthenic are among them. The asthenic patient is usually thin and frail. The hyposthenic patient is slim and falls in between the sthenic and asthenic body habitus types. A patient with an average build and a moderate amount of body weight is the sthenic patient. We also refer to this as mesomorphic. The hypersthenic patient has a bulky, hefty build.
129 - Relationship between exposure rate and beam filtration:
A. As beam filtration increases, exposure decreases
B. Beam filtration and exposure rate exhibit a direct relationship
C. As beam filtration increases, entrance skin exposure to the patient increases
D. A and B
E. B and C
Correct Answer: A. As beam filtration increases, exposure decreases
Explanation:
The rate of entrance skin exposure to the patient decreases when more filtering is applied to the primary X-ray beam. There is an inverse relationship between exposure rate and beam filtration.
A. As beam filtration increases, exposure decreases
Explanation:
The rate of entrance skin exposure to the patient decreases when more filtering is applied to the primary X-ray beam. There is an inverse relationship between exposure rate and beam filtration.
130 - What is the main objective of beam filtration?
A. Increase the quality and quantity of the primary beam
B. Increase beam penetrability
C. Remove high-energy X-ray photons
D. To reduce entrance skin exposure to the patient
D. To reduce entrance skin exposure to the patient
Reducing the patient’s entrance skin exposure is the main goal of filtration. Filtration hardens the primary beam by removing low-energy, non-diagnostic X-ray photons from it. Filtration does not affect beam penetrability, but it does raise the beam’s effective energy and quality.
131 - What is the effect of beam filtration on average beam energy?
A. Filtration increases the primary X-ray beam’s effective energy and quality
B. Filtration has no effect on the energy of the primary X-ray beam
C. Filtration decreases the “hardness” of the X-ray beam
D. Filtration decreases the quality of the remnant beam
A. Filtration increases the primary X-ray beam’s effective energy and quality
Filtration hardens the primary beam by removing low energy, non-diagnostic X-ray photons from it. Filtration does not affect beam penetrability, but it does raise the beam’s effective energy and quality.
132 - According to NCRP #102, when operating over 70 kVp, the minimum thickness requirements for total filtration are:
A. 0.5 mm aluminum
B. 1.5 mm aluminum
C. 2.5 mm aluminum
D. 3.5 mm aluminum
C. 2.5 mm aluminum
The minimum thickness needed for total filtration varies depending on the operating kVp, as per NCRP #102. The total of added and inherent filtration is referred to as total filtration. It is necessary to use at least 0.5 mm of aluminum when operating below 50 kVp. It is admissible to use 1.5 mm aluminum between 50 and 70 kVp. The minimum thickness of aluminum required for operation over 70 kVp is 2.5 mm.
133 - What is the Al equivalent of the X-ray tube’s inherent filtration?
A. 0.8 and 1.6 mm
B. 2.5 and 3.0 mm
C. 0.5 and 1.0 mm
D. 0.2 and 0.5 mm
C. 0.5 and 1.0 mm
Filtration that is inherent to the X-ray tube stems from the design of the tube itself. Typically, inherent filtration has an Al equivalent of 0.5 to 1.0 mm. Added filtration is any material placed in the path of the primary X-ray beam, most commonly layers of aluminum. Usually, the purpose of adding these layers is to raise the total amount of filtering to the necessary minimum standards. The sum of the inherent and added filtration is known as total filtration.
134 - Individuals who are exposed to radiation at work must utilize devices that track and document the radiation they are exposed to over a specified amount of time. Which personal dosimeters are most frequently used?
A. Optically stimulated luminescence dosimeter
B. Thermoluminescent dosimeter
C. Film badge dosimeter
D. Self-reading dosimeter
E. A, B, and C
Correct Answer: E. A, B, and C
Those who are exposed to radiation at work must wear equipment to monitor and document the radiation they are exposed to during a specified length of time, usually one month. The three personal dosimeters that are most used are OSL, TLD, and film badges; among the three, film badge dosimeters are the most economical and widely utilized. These devices are designed solely to record exposures from the workplace
135 - Exposure to the image receptor will double if kVp is raised by:
A. 30%
B. 50%
C. 15%
D. 5%
C. 15%
Reducing mAs can greatly lessen patient exposure. With a change in mAs, kVp must be modified to maintain radiographic density. A 15% increase in kVp will double the density; a 15% decrease in kV will cut the density in half. This is known as the 15% rule. For instance, if mAs is lowered by half (i.e., from 40 to 20) to decrease patient exposure, kVp should be raised by 15% to double exposure to the IR.
136 - Regarding the use of grids, which of the following is false?
A. An alternative to utilizing a grid is the air gap technique
B. Grids are used for body parts that are greater than 6 centimeters thick
C. Using a grid necessitates greater exposure than a radiograph produced without a grid
D. By limiting the amount of secondary and scattered radiation that reaches the IR, the use of grids greatly increases radiographic contrast
B. Grids are used for body parts that are greater than 6 centimeters thick
Grids help increase radiographic contrast by reducing the amount of scattered and secondary radiation that reaches the image receptor. Grids are used for body parts thicker than 10 centimeters.
137 - An alternative to using a grid is the air gap technique. Which of the following is required in order to employ this technique?
A. It is necessary to have a long SID
B. An increased OID is required
C. A short SID must be used
D. B and C
E. A and B
E. A and B
An alternative to using a grid is to employ the air gap technique. It necessitates using a longer SID in conjunction with a higher OID. The utilization of the air gap technique leads to a significant percentage of secondary and scattered radiation diverging away from the IR, which reduces their effect on the radiographic image, but does not diminish secondary or scattered radiation output. The primary purpose of the air gap technique is to enhance radiographic contrast.
138 - How does a fluoroscopic dead man switch operate?
A. The fluoroscopic table recognizes the patient’s weight and emits X-rays
B. A fluoroscopy timer emits X-rays for a specified period of time
C. Qualified personnel must depress a foot pedal or hold a switch to emit X-rays
D. A switch is turned on and the beam is emitted until the switch is turned off
C. Qualified personnel must depress a foot pedal or hold a switch to emit X-rays
All varieties of fluoroscopes are controlled by means of a “dead man” switch. That is to say, X-rays are only produced and emitted when a properly qualified individual is actively pressing the foot pedal or using the switch. The fluoroscopic image is created and X-rays are emitted when the pedal is depressed.
140 - Fluoroscopic examinations expose patients to a higher dose of radiation compared to conventional radiographic examinations. What is the reason for this?
A. A greater exposure time is required
B. The patient and X-ray photon source are closer together
C. The X-ray beam used with fluoroscopy is “harder” than the conventional radiographic X-ray beam
D. A single 3-dimensional image is captured for later analysis using a greater quantity of X-ray photons
E. A and B
E. A and B
Fluoroscopy is a procedure that may necessitate a larger patient dose compared to a standard radiographic imaging examination. This is primarily because, unlike overhead imaging, the source of X-ray photons is closer to the patient. Guidelines for minimum source-to-skin distance (SSD), maximum tube output, collimation, timer, and exposure switch parameters, among other things, are provided by NCRP recommendations. Lower patient dose is one benefit of digital fluoroscopy compared to conventional fluoroscopy. The fact that the X-ray beam used in digital fluoroscopy is pulsed rather than continuous is the main factor which reduces the patient exposure.
141 - Where is the secondary radiation grid positioned during a fluoroscopic examination in order to minimize incident forward scattered radiation?
A. Furthest distance from the imaging detector
B. Nearest to the X-ray tube
C. Nearest the image intensifier
D. Closest to the X-ray source
C. Nearest the image intensifier
The following suggestions aim to minimize exposure to patients and operators while optimizing image quality. The patient should be positioned as far from the X-ray tube and as close to the image intensifier input as feasible. This produces a crisper image and reduces the patient entrance dose. Operator vigilance is required when utilizing the exposure pedal. When possible, the operator should use pulsed fluoroscopy and last image hold. They should also use the lowest field of view, only use high dosage and detail modes when necessary, and use magnification mode sparingly. Additionally, to reduce the amount of radiation that healthcare personnel are exposed to, the X-ray tube should be positioned underneath the patient.
142 - How much fluoroscopic time must elapse before the fluoroscopy timer emits a signal?
A. 5 minutes
B. 30 seconds
C. 2 minutes
D. 1 minute
A. 5 minutes
A fluoroscopy timer that will sound or stop exposure after five minutes is necessary for radiation safety.
143 - A modification in SID triggers an adjustment in the fluoroscopic automatic brightness control (ABC) feature. Which of these statements is true as SID decreases?
A. As SID decreases, intensity of the x-ray photons at the image intensifier’s input phosphor increases
B. The ABC would decrease milliamperage to compensate for an increase in X-ray photon intensity at the image intensifier
C. The ABC ensures constant brightness and corrects for variations in X-ray beam attenuation
D. B and C
E. A, B, and C
Correct Answer: E. A, B, and C
As SID is decreased, the intensity of the x-ray photons at the image intensifier’s input phosphor increases, stimulating the automatic brightness control (ABC) to decrease the milliamperage and thereby decreasing patient dose. The ABC ensures constant brightness and contrast of the output screen image by correcting for variations in x-ray beam attenuation with adjustments in kilovoltage and/or milliamperage.
144 - Automatic exposure rate control (AERC) functions to:
A. Generate pulses of radiation
B. Limit any variance in image quality during the examination
C. Uphold a preset degree of radiation exposure per frame
D. Increase diameter of the optical coupling device
E. B and C
E. B and C
Throughout the examination, automatic exposure rate control keeps the radiation dose per frame at a preset level, according to the patient’s anatomy’s attenuation characteristics and maintaining a constant degree of image quality
145 - Which fluoroscopic device serves to transform the X-ray beam intensity pattern into an image that can be recorded by a video camera and shown on a video display monitor?
A. Image intensifier
B. Optical coupling device
C. Collimator
D. Photocathode
A. Image intensifier
An electronic device known as the X-ray image intensifier, also called the image receptor, transforms the X-ray beam intensity pattern (remnant beam) into a visible image that may be recorded by a video camera and shown on a video display monitor. An output phosphor, electron optics, photocathode, and an input phosphor layer are the essential parts of an X-ray image intensifier.
146 - What effect does fluoroscopic magnification mode have on patient dose?
A. Using magnification mode reduces patient dose
B. Patient dose is increased while using magnification mode
C. The degree of patient exposure and the use of the magnification mode are inversely related
D. Use of magnification is unrelated to patient dose
B. Patient dose is increased while using magnification mode
A few strategies to reduce the amount of radiation that a patient receives during a fluoroscopic examination are shortening the fluoroscopic exposure time, using last image hold, positioning the patient as close to the image intensifier as feasible, utilizing an automatic brightness control (ABC) setting with the highest kVp and lowest mAs combination, limiting the use of boost and magnification modes, using collimation and the smallest field of view, using the lowest acceptable pulse rate, and adjusting the tube angle or patient position to distribute the dose over a greater anatomic area.
147 - The Food and Drug Administration (FDA) currently requires that all fluoroscopes sold in the United States be able to display:
A. Optically stimulated luminescence dosimetry value
B. Peak skin dose
C. Kerma-area product
D. Total air kerma
D. Total air kerma
Presently, all fluoroscopes sold in the United States are mandated by the Food and Drug Administration (FDA) to be able to display the total air kerma at the interventional reference point. The International Electrotechnical Commission refers to this quantity as reference air kerma (RAK). Most fluoroscopes also have the ability to show the kerma-area product (KAP). Peak skin dose (PSD) estimation is a valuable tool that can be performed with RAK or KAP. There is a predilection for RAK in the United States.
148 - What is the name of the dose-reducing feature that shows a saved fluoroscopic image from the most recent fluoroscopic exposure?
A. Last image hold
B. Automatic brightness control
C. Pulsed exposure
D. Boost mode
A. Last image hold
The most recent fluoroscopic image can be saved on the monitor using a function called “last image hold,” which eliminates the requirement for continuous x-ray exposure during a fluoroscopic examination.
149 - When mAs is increased from 10 to 30 the patient will be exposed to more radiation by a factor of:
A. 3
B. 10
C. 9
D. 20
A. 3
Quantity of radiation in the X-ray beam and rate at which radiation is administered to the patient are directly impacted by milliampere-seconds (mAs). Patient exposure increases by a factor of two if mAs is increased from 5 to 10. The radiation exposure to the patient increases by a factor of three when mAs is raised from 10 to 30.
150 - Which of the following is considered the best method for limiting the amount of radiation exposure patients receive?
A. Limiting the radiation field and the primary X-ray beam
B. Use of a collimator
C. Adjustment of patient positioning
D. Use of a phototimer
E. A and B
E. A and B
Perhaps the best method for limiting the amount of radiation that patients are exposed to is to limit the irradiated field size using beam restriction techniques like collimation. Other strategies that help limit patient dose include patient positional adjustments and effective communication with the patient to minimize the need for repeat exposures. For instance, if less exposure to anterior organs is desired, PA projections are favored over AP projections.
151 - With regard to personnel monitoring, an external whole-body exposure equivalent at a tissue depth of 1 centimeter delineates:
A. Committed dose equivalent
B. Deep dose equivalent
C. Total effective dose equivalent
D. Shallow dose equivalent
B. Deep dose equivalent
The external whole-body exposure equivalent at a tissue depth of 1 centimeter is known as the deep dose equivalent (DDE). The shallow dose equivalent (SDE) is the external skin or extremity exposure measured as the dose equivalent at a tissue depth of 0.007 cm, averaged across a 1 square centimeter area. The eye dose equivalent, committed dosage equivalent, committed effective dose equivalent, and total effective dose equivalent are additional metrics that can be used to evaluate personnel exposure monitoring.
152 - For fixed fluoroscopic systems, what is the minimum source-to-skin distance recommended by NCRP #102 and Code of Federal Regulation-21?
A. 18 inches
B. 15 inches
C. 10 inches
D. 12 inches
B. 15 inches
For fixed fluoroscopic systems, the minimum distance from source to skin is 15 inches. A minimum of 12 inches for source-to-skin distance is recommended when using mobile fluoroscopic equipment.
153 - The minimum thickness of an absorbent material needed to decrease radiation intensity to one-half of its initial value is called:
A. Broad-beam absorption
B. Half-value layer
C. Incidence reduction
D. Linear attenuation coefficient
B. Half-value layer
The thickness of material needed to cut an X-ray or gamma-ray beam’s intensity to one-half of its original value is known as half-value layer (HVL).
154 - Which of the following describes the amount of tissue that has been exposed to radiation and the radiation dose?
A. Total effective dose equivalent
B. Dose area product (DAP)
C. Half-value layer
D. Committed dose equivalent
Correct Answer: B. Dose area product (DAP)
The radiation dose exiting the X-ray tube multiplied by the area of the X-ray field is expressed as the Dose Area Product (DAP). DAP meters calculate the product of the X-ray field’s area and in-air radiation. To determine the maximum radiation skin exposure, a DAP meter should be utilized.
155 - Time, distance, and shielding are the three guiding concepts of radiation protection. The most effective approach for protecting personnel among these three is thought to be distance. If the radiographer moves from 5 to 10 feet away from the radiation source according to the inverse square law, what is the resulting dose?
A. Dose increases by a factor of four
B. Dose decreases by half
C. Dose decreases by a factor of four
D. Dose doubles
C. Dose decreases by a factor of four
The idea of dose reduction with increasing distance from the source is explained by the inverse square law. According to this law, radiation intensity is inversely proportional to the square of the distance from the source of radiation. Given an area (A) and a sphere radius (r), the region over which a radiation dose is spread rises in accordance with the formula A = 4πr². The dose is relative to the inverse of the square of the radius. Therefore, the dose will be reduced by a factor of four by doubling the distance. The amount of radiation to which the body is exposed can be decreased by applying this technique.
156 - Healthcare workers may be exposed to secondary radiation from which of the following sources?
A. Scatter from the patient
B. Radiation emitted from the window port of the X-ray tube
C. Radiation emitted from the tube housing
D. A and C
E. A, B, and C
D. A and C
The primary X-ray beam, secondary radiation exposure, and the patient themselves are all potential sources of radiation exposure. It is important that the primary X-ray beam only penetrate the part that is being examined. If necessary, only a non-occupationally exposed person wearing a lead apron should hold the patient. This lowers the radiographer’s inadvertent exposure to the primary beam and minimizes their cumulative occupational exposure. Secondary radiation exposure is a result of both scatter and leakage radiation. Secondary radiation exposure is influenced by Compton effect and classical scattering. Particularly during fluoroscopic exams, the patient may serve as a source of scatter radiation. By using appropriate shielding and keeping a safe distance from the patient, occupational exposure to side scatter radiation from portable and fluoroscopic procedures can be reduced. Leakage radiation is any radiation that leaves the X-ray tube through an opening other than the window port. When the tube is working at its maximum kVp and mA, leakage should be controlled at or below 100 mR/hour (0.001 Sv) at 1 meter.
157 - When the X-ray tube is operating at maximum kVp and mA, leakage radiation should not exceed:
A. 52 mR/hr at 40 inches
B. 100 mR/hr at 1 meter
C. 80 mR/hr at 72 inches
D. 75 mR/hr at 1 meter
B. 100 mR/hr at 1 meter
The primary X-ray beam, secondary radiation exposure, and the patient themselves are all potential sources of radiation exposure. It is important that the primary X-ray beam only penetrate the part that is being examined. If necessary, only a non-occupationally exposed person wearing a lead apron should hold the patient. This lowers the radiographer’s inadvertent exposure to the primary beam and minimizes their cumulative occupational exposure. Secondary radiation exposure is a result of both scatter and leakage radiation. Secondary radiation exposure is influenced by Compton effect and classical scattering. Particularly during fluoroscopic exams, the patient may serve as a source of scatter radiation. By using appropriate shielding and keeping a safe distance from the patient, occupational exposure to side scatter radiation from portable and fluoroscopic procedures can be reduced. Leakage radiation is any radiation that leaves the X-ray tube through an opening other than the window port. When the tube is working at its maximum kVp and mA, leakage should be controlled at or below 100 mR/hour (0.001 Sv) at 1 meter.
158 - How can healthcare organizations apply the fundamentals of radiation protection to reduce radiographer exposure?
A. If the radiographer’s presence is not necessary to complete the examination, they should leave the X-ray room during the exposure
B. A designated fluoroscopic technologist should be appointed
C. The X-ray technologist should stay as far away as is practical from the area of exposure
D. A and C
E. A, B, and C
Correct Answer: D. A and C
Time, distance, and shielding are three fundamentals of radiation protection. This means that the radiographer should reduce the amount of time they spend near a source of radiation, increase the distance between themselves and the source, and employ a barrier or shielding device between themselves and the source to minimize their amount of radiation exposure. For example, healthcare organizations may rotate technologists through fluoroscopic examinations to decrease individual occupational dose.
159 - According to NCRP Report #102, which protective device in a fluoroscopic setting is required to have a minimum lead equivalent of 0.5 mm Pb?
A. Spot film device protective curtain
B. Lead apron
C. Bucky slot cover
D. Glasses
B. Lead apron
Shielding and aprons are examples of protective devices that serve to protect patients and healthcare professionals from exposure to ionizing radiation. To minimize radiation exposure, primary and secondary protective barriers exist. The NCRP #102 specifies a minimum lead equivalent for a range of protective devices. Lead aprons, thyroid shields, and the transparent lead-plastic overhead protective barrier are examples of protective devices having a minimum lead equivalent of 0.5 mm Pb. Gloves, a protective curtain for spot film devices, and bucky slot covers are examples of protective equipment with a minimum lead equivalent of 0.25 mm Pb. Protective glasses have a minimum lead equivalent of 0.35 mm Pb.
160 - Given the guidelines for fluoroscopy and portable units provided by NCRP #102 and Code of Federal Regulation-21, what is the maximum exposure at the tabletop of a fluoroscopic unit?
A. 10 R/minute (100 mGy/minute)
B. <2.1 R/minute (21 mGy/minute) for each mA of operation at 80 kVp
C. 5 R/minute (50 mGy/minute)
D. <0.6 R/minute (6 mGy/minute) for each mA of operation at 75 kVp
E. A and B
E. A and B
For fluoroscopic and portable units, the maximum exposure at the tabletop of a fluoroscopic device is 10 R/minute (100 mGy/minute), or it cannot exceed 2.1 R/minute (21 mGy/minute) for each mA of operation at 80 kVp, as per NCRP #102 and Code of Federal Regulation-21 standards. Conventional (non-digital) fluoroscopic equipment typically functions in the 2 to 5 mA range.
161 - What is the total exposure if the fluoroscopy time is 3.2 minutes, and 6 mA is used at 80 kVp?
A. 12.6 R
B. 40.32 R
C. 13 mA
D. 6 mA
Correct Answer: B. 40.32 R
2.1 R/minute (21 mGy/min) x 6 mA = 12.6 R/minute (126 mGy/min). Given that the fluoroscopy examination time was 3.2 minutes, the total exposure is equal to 12.6 R/minute (126 mGy/minute) x 3.2 minutes = 40.32 R (403.2 mGy). For fluoroscopic and portable units, the maximum exposure at the tabletop of a fluoroscopic device is 10 R/minute (100 mGy/minute), or it cannot exceed 2.1 R/minute (21 mGy/minute) for each mA of operation at 80 kVp, as per NCRP #102 and Code of Federal Regulation-21 standards
162 - Lithium fluoride is the functional component used in which type of dosimeter?
A. Proportional counter
B. Cutie pie instrument
C. Thermoluminescent dosimeter
D. Film badge
E. Optically stimulated luminescent dosimeter
C. Thermoluminescent dosimeter
Dosimeters come in a variety of forms and employ various methods for measuring radiation. These consist of a proportional counter, a film badge, a thermoluminescent dosimeter, a gas ionization chamber instrument, a pocket dosimeter, and an optically stimulated luminescent dosimeter.
The functional element of a thermoluminescent dosimeter (TLD) is lithium fluoride. The light spectrum that the chip produces varies according to the energy levels that it absorbs. While TLDs are more costly than film badges, they are less prone to reading errors or artifacts. One drawback of using a TLD is that, after the chip is heated, it is destroyed and no archival record is kept aside from a written report of findings.
A permanent or archival record of radiation exposure is provided by a film badge. It depends on ionizing radiation’s capacity to alter the film emulsion’s density. The degree of film blackening on the film emulsion surfaces under various types of attenuating filters, such as copper or tin, determines how much of the dose that the badge receives. Film badges have the advantage of being reliable and cost-effective. Long-term radiation monitoring can be successfully accomplished using film badges.
A pocket dosimeter works by using ionization to modify the charge of an electrode, which discharges the electrode, by ionizing a gas inside a sealed chamber. Although a pocket dosimeter can be recharged and used again, it does not provide a permanent record of dosage.
Using an aluminum oxide detector, optically stimulated luminescence dosimeters (OSLD) enable the distinction of radiation energy levels and between deep, shallow, and ocular exposure. After being read by a laser light, the sensing material illuminates in direct proportion to the amount of exposure it received. This type of radiation dosimeter is worn by radiographers at many medical facilities.
For area surveys, a device known as the “cutie pie” is a gas ionization chamber instrument that monitors exposure rate. Although it can measure a wide range of exposures in a short amount of time, this instrument is not suitable for measuring radiation doses from brief exposure times.
In the context of diagnostic medical imaging, a proportional counter is not employed. Alpha radiation, beta radiation, and other trace levels of radioactivity are detectable with a proportional counter.
163 - What value cannot be exceeded by the NCRP dose restrictions for the embryo during the entire gestational period?
A. 0.05 rem (0.0005 Sv, 0.5 mSv)
B. 0.8 rem (8 mSv)
C. 0.5 rem (5 mSv)
D. 0.25 rem (2.5 mSv)
C. 0.5 rem (5 mSv)
Embryonic exposure must not exceed NCRP standards of 0.5 rem (5 mSv) for the duration of the gestational period and 0.05 rem (0.05 mSv) in any month after the pregnancy is confirmed.
164 - How long must occupational exposure records be kept for healthcare personnel exposed to ionizing radiation in the workplace?
A. 1 year
B. 6 months
C. The duration of the individual’s employment
D. The duration of the individual’s lifetime
C. The duration of the individual’s employment
For the duration that the employee works in medical imaging, occupational exposure records must be maintained.
165 - According to NCRP #116, the yearly total body exposure for those who are occupationally exposed to ionizing radiation is:
A. 5 rem
B. 60 mSv
C. 50 rem
D. 15 rem
E. 150 mSv
A. 5 rem
Under NCRP #116, ionizing radiation exposure at work is limited to the following annual exposure levels: 5 rem (50 mSv) for the whole body, 15 rem (150 mSv) for the lens of the eye, and 50 rem (500 mSv) for all other areas, including the breast, lung, gonadal, dermal tissues, extremities, and red bone marrow.
