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DANB CDA practice questions

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Question 1Radiation Health and Safety

What is the primary purpose of the collimator in an intraoral X-ray unit?

  1. To store the exposed image receptor after use
  2. To increase the kilovoltage delivered to the tube
  3. To filter out low-energy photons from the beam
  4. To restrict the size of the useful X-ray beam as it leaves the tubehead Correct answer.

Explanation

The collimator (position-indicating device, or PID) shapes and limits the diameter of the emerging X-ray beam, reducing patient exposure to tissues outside the area of interest. Beam filtration is a separate function performed by aluminum discs in the path of the beam.

Question 2Radiation Health and Safety

The recommended diameter of the collimated X-ray beam at the end of the PID for an intraoral unit operating above 70 kVp is:

  1. 2.75 inches Correct answer.
  2. 3.5 inches
  3. 4.5 inches
  4. 1.5 inches

Explanation

For units operating above 70 kVp, the beam at the end of the PID must not exceed 2.75 inches in diameter. Units operating at or below 70 kVp are limited to a 2.75-inch beam as well under current recommendations, having replaced the older 1.75-inch standard.

Question 3Radiation Health and Safety

Which device is used to measure the absorbed dose received by a dosimeter badge worn by a dental radiographer?

  1. A thermoluminescent dosimeter Correct answer.
  2. A pinhole camera
  3. A step wedge
  4. A densitometer

Explanation

A thermoluminescent dosimeter contains lithium fluoride crystals that store energy when exposed to radiation and release light when heated, allowing the accumulated dose to be measured. Step wedges, densitometers, and pinhole cameras are used for quality assurance of images, not personnel monitoring.

Question 4Radiation Health and Safety

Where should a radiation worker's dosimeter badge be worn during routine dental radiography?

  1. Clipped to the wrist of the dominant hand
  2. At collar level outside the lead apron Correct answer.
  3. Under the lead apron at waist level
  4. Attached to the control panel of the unit

Explanation

The badge is worn at collar level outside any protective apron so that it records the dose to the most radiosensitive exposed area, the head and neck. If a second badge is used under the apron, it is in addition to the collar badge, not a replacement.

Question 5Radiation Health and Safety

Which of the following best describes the ALARA concept as applied in dental radiography?

  1. Exposures should be kept as low as reasonably achievable while still obtaining needed diagnostic information Correct answer.
  2. Every patient should receive a full-mouth series at each recall appointment
  3. Radiographs should be avoided entirely unless the patient requests them
  4. Exposure time should be increased to guarantee a high-contrast image

Explanation

ALARA means making every reasonable effort to keep radiation dose as low as reasonably achievable, consistent with obtaining the diagnostic information required. It does not prohibit radiographs; it requires that each exposure be justified and optimized.

Question 6Radiation Health and Safety

What is the purpose of adding aluminum filtration to the X-ray tubehead?

  1. To reduce the kilovoltage reaching the anode
  2. To focus the beam onto the image receptor
  3. To absorb low-energy photons that would otherwise increase patient dose without contributing to the image Correct answer.
  4. To increase the number of high-energy photons reaching the receptor

Explanation

Filtration preferentially removes low-energy, longer-wavelength photons that would be absorbed by the patient's skin and superficial tissues without improving the diagnostic image. This lowers patient dose and hardens the beam.

Question 7Radiation Health and Safety

A dentist asks the radiographer to retake an image because the anterior teeth appear foreshortened. Which error most likely caused this?

  1. The PID was too close to the patient's face
  2. The exposure time was too short
  3. The central ray was directed perpendicular to the receptor
  4. The receptor was positioned at too steep an angle relative to the long axis of the teeth Correct answer.

Explanation

Foreshortening occurs when the receptor is not parallel to the long axis of the teeth, so the teeth are projected at an angle and appear shortened. Correct paralleling technique with the receptor parallel and the central ray perpendicular prevents this distortion.

Question 8Radiation Health and Safety

Which technique positions the image receptor parallel to the long axis of the teeth and directs the central ray perpendicular to both?

  1. Lateral jaw projection
  2. Bisecting-angle technique
  3. Paralleling technique Correct answer.
  4. Occlusal technique

Explanation

In the paralleling technique the receptor is placed parallel to the long axis of the tooth and the central ray is directed perpendicular to the receptor, minimizing distortion. The bisecting-angle technique instead places the receptor against the teeth and angles the beam to bisect the angle.

Question 9Radiation Health and Safety

How does increasing the source-to-receptor distance affect the image when exposure factors are adjusted to maintain density?

  1. Magnification decreases and sharpness improves Correct answer.
  2. Magnification and sharpness both remain unchanged
  3. Contrast increases while sharpness decreases
  4. Magnification increases and sharpness decreases

Explanation

A longer source-to-receptor distance reduces magnification and improves image sharpness because the beam is less divergent at the receptor. Exposure time must be increased to compensate for the reduced intensity at the longer distance.

Question 10Radiation Health and Safety

Which exposure factor primarily controls the contrast of a dental radiograph?

  1. Source-to-receptor distance
  2. Exposure time
  3. Milliamperage
  4. Kilovoltage Correct answer.

Explanation

Kilovoltage determines the energy of the X-ray beam and thus the subject contrast between tissues of differing density. Higher kVp produces a longer scale of contrast, while lower kVp produces higher contrast.

Question 11Radiation Health and Safety

What is the function of the lead apron worn by the patient during dental radiography?

  1. To absorb scattered radiation that would otherwise reach the patient's trunk and gonads Correct answer.
  2. To shield the operator from the primary beam
  3. To reduce scatter reaching the image receptor
  4. To protect the patient's thyroid from the primary beam

Explanation

A lead apron protects the patient's body, particularly the reproductive organs and other radiosensitive tissues, from scatter produced within the patient. A thyroid collar is used separately to shield the neck.

Question 12Radiation Health and Safety

Which of the following is the most effective way for the radiographer to reduce occupational exposure during intraoral radiography?

  1. Standing directly in line with the primary beam
  2. Holding the receptor in the patient's mouth with a gloved hand
  3. Standing behind a proper barrier and at least 6 feet from the patient during exposure Correct answer.
  4. Increasing the exposure time to finish more quickly

Explanation

Distance and shielding are the most effective protections: the operator should stand behind a barrier and at least 6 feet from the patient, out of the path of the primary beam. Holding the receptor exposes the operator's hand to the beam and is never acceptable.

Question 13Radiation Health and Safety

A radiographer exposes a receptor while standing 3 feet from the patient without a barrier. What is the main concern?

  1. The image will be overexposed
  2. The patient will receive a larger primary beam
  3. Occupational dose from scatter is substantially higher than at the recommended distance Correct answer.
  4. The tubehead will overheat

Explanation

Scatter intensity falls off rapidly with distance, so standing only 3 feet away without a barrier results in a much higher occupational dose than standing at least 6 feet away behind a barrier. The image and patient dose are not directly affected by the operator's position.

Question 14Radiation Health and Safety

Which of the following best describes the purpose of a radiation protection program in a dental office?

  1. To replace the need for personnel dosimeters
  2. To establish policies and procedures that keep occupational and patient doses as low as reasonably achievable Correct answer.
  3. To eliminate the requirement for quality assurance testing
  4. To guarantee that no radiation exposure ever occurs

Explanation

A radiation protection program sets policies, training, and monitoring to keep exposures as low as reasonably achievable and to comply with regulations. It complements, rather than replaces, dosimetry and quality assurance.

Question 15Radiation Health and Safety

What is the maximum permissible occupational whole-body dose recommended for radiation workers?

  1. 500 mSv (50 rem) per year
  2. 50 mSv (5 rem) per year Correct answer.
  3. 5 mSv (0.5 rem) per year
  4. 0.5 mSv (0.05 rem) per year

Explanation

The recommended annual occupational dose limit for radiation workers is 50 mSv (5 rem) to the whole body. The public limit is much lower, at about 1 mSv per year.

Question 16Radiation Health and Safety

Which of the following statements about the primary beam is correct?

  1. It should never be directed toward the operator or any person other than the patient Correct answer.
  2. It is safe to direct toward the operator if a lead apron is worn
  3. It contains only low-energy photons
  4. It is identical in intensity to scattered radiation

Explanation

The primary beam is the most intense radiation and must be directed only at the patient's area of interest, never toward the operator or others. Scatter is far less intense than the primary beam but still requires protection.

Question 17Radiation Health and Safety

A patient who is pregnant requires a dental radiograph for an urgent diagnosis. What is the appropriate approach?

  1. Increase exposure time to reduce the number of retakes
  2. Take a full-mouth series to gather all information at once
  3. Take only the radiographs needed for diagnosis, using proper shielding and technique Correct answer.
  4. Refuse all radiographs until after delivery

Explanation

Pregnancy is not an absolute contraindication to needed dental radiographs. The principle is to justify each exposure and optimize technique with shielding so that only necessary images are made.

Question 18Radiation Health and Safety

Which of the following is a responsibility of the radiographer regarding quality assurance of the X-ray unit?

  1. Periodically checking beam alignment, collimation, and exposure reproducibility Correct answer.
  2. Repairing the high-voltage transformer personally
  3. Removing the filtration to increase beam intensity
  4. Adjusting the kilovoltage setting without documentation

Explanation

Quality assurance includes routine checks of beam alignment, collimation, exposure reproducibility, and other performance parameters to ensure the unit operates safely and consistently. Repairs to high-voltage components must be performed by qualified service personnel.

Question 19Radiation Health and Safety

What is the purpose of a film badge or dosimeter report review?

  1. To detect whether a worker's exposure is approaching or exceeding established limits Correct answer.
  2. To verify the density of processed radiographs
  3. To determine the correct exposure time for each patient
  4. To measure the kilovoltage output of the tube

Explanation

Dosimeter reports provide a record of accumulated occupational dose so that exposures approaching or exceeding limits can be identified and investigated. They do not set patient exposure factors or measure image density.

Question 20Radiation Health and Safety

Which of the following best explains why the bisecting-angle technique may produce more image distortion than the paralleling technique?

  1. The receptor is always parallel to the teeth
  2. The technique uses a longer source-to-receptor distance
  3. The central ray is always perpendicular to the receptor
  4. The receptor is placed at an angle to the teeth, and the central ray must be angled to bisect the angle Correct answer.

Explanation

In the bisecting-angle technique the receptor cannot be placed parallel to the teeth, so the central ray is angled to bisect the angle between the receptor and the tooth axis. This angulation can introduce distortion if the angle is not estimated accurately.

Question 21Radiation Health and Safety

Which of the following is the correct action if a radiographer's dosimeter is accidentally left in the sun or exposed to heat?

  1. Report it and obtain a replacement, since the reading may be invalid Correct answer.
  2. Remove the badge from the program
  3. Use the reading as normal without reporting
  4. Ignore it, because heat does not affect the badge

Explanation

Dosimeters can be affected by environmental conditions such as heat, sunlight, and moisture, which may invalidate the recorded reading. The worker should report the incident and obtain a replacement badge so that monitoring remains accurate.

Question 22Radiation Health and Safety

Which of the following structures is most radiosensitive and therefore of greatest concern when shielding a patient during dental radiography?

  1. The alveolar bone
  2. The enamel of the teeth
  3. The keratinized gingiva
  4. The thyroid gland and reproductive organs Correct answer.

Explanation

The thyroid gland and reproductive organs are among the more radiosensitive tissues in the head and neck region and trunk, so they are shielded with a thyroid collar and lead apron. Mature enamel, bone, and keratinized tissue are relatively radioresistant.

Question 23Radiation Health and Safety

What is the effect of reducing the source-to-receptor distance without changing other exposure factors?

  1. The beam intensity and magnification both remain unchanged
  2. The beam intensity decreases and magnification decreases
  3. The beam intensity at the receptor increases and magnification increases Correct answer.
  4. The beam intensity increases and magnification decreases

Explanation

Moving the source closer increases the intensity at the receptor according to the inverse square law and also increases magnification because the beam is more divergent. Exposure factors must be adjusted to compensate.

Question 24Radiation Health and Safety

Which of the following is an example of a dose-reduction measure specific to intraoral radiography?

  1. Increasing the collimator diameter
  2. Using the fastest image receptor speed compatible with diagnostic needs Correct answer.
  3. Increasing exposure time to reduce retakes
  4. Removing the aluminum filter

Explanation

Faster image receptors require less exposure to produce a diagnostic image, directly reducing patient dose. Increasing collimation diameter, removing filtration, or lengthening exposure time all increase dose.

Question 25Radiation Health and Safety

A radiographer notices that the beam alignment test shows the central ray is off-center. What is the appropriate response?

  1. Continue using the unit but increase exposure time
  2. Document the finding and continue until the next annual inspection
  3. Reduce the collimator size to compensate
  4. Remove the unit from service and arrange for service before further patient exposures Correct answer.

Explanation

A misaligned beam means the patient may be exposed to radiation without the intended diagnostic benefit and the image may be distorted. The unit should be taken out of service and serviced before further use.

Question 26Radiation Health and Safety

Which tissue interaction with the primary X-ray beam produces the photons responsible for creating the latent image on an intraoral receptor?

  1. Photoelectric absorption within the receptor phosphor
  2. Compton backscatter from the PID housing
  3. Coherent (unmodified) scattering by soft tissue
  4. Differential attenuation of the beam as it passes through tissues Correct answer.

Explanation

The latent image forms because different tissues absorb the beam to different degrees, so the receptor receives a pattern of varying intensities. This differential attenuation is the basis of radiographic contrast and image formation.

Question 27Radiation Health and Safety

A dental radiographer must hold the receptor for a patient who cannot stabilize it. Which approach reflects accepted radiation protection practice?

  1. The radiographer uses a receptor-holding device and asks the patient to stabilize it
  2. The radiographer holds the receptor with a lead-lined glove while standing in the primary beam
  3. The radiographer avoids holding the receptor and uses a positioning device or other stabilization method Correct answer.
  4. The radiographer holds the receptor only if no holder is available and no one else can assist

Explanation

No one should hold a receptor in the primary beam during an exposure. Beam-holding devices, receptor holders, and stabilization aids should be used so that neither the radiographer nor the patient's hands are exposed unnecessarily.

Question 28Radiation Health and Safety

What is the primary purpose of collimation in dental X-ray equipment?

  1. To shorten the exposure time required for a diagnostic image
  2. To convert the alternating current into direct current
  3. To restrict the size of the useful beam and reduce irradiated tissue volume Correct answer.
  4. To increase the energy of the emitted photons

Explanation

Collimation limits the dimensions of the X-ray beam so that only the region of interest is exposed. This reduces the volume of patient tissue irradiated and lowers scatter production.

Question 29Radiation Health and Safety

A radiographer is preparing to expose a maxillary molar periapical receptor and wants to minimize the patient's thyroid dose. Which action is most appropriate?

  1. Using a longer PID to increase the source-to-receptor distance
  2. Asking the patient to hold the receptor with a lead glove
  3. Placing a lead thyroid collar on the patient Correct answer.
  4. Increasing the kilovoltage to shorten the exposure

Explanation

A lead thyroid collar shields the thyroid gland, which is one of the more radiosensitive organs in the head and neck region. Shielding is a direct dose-reduction measure for the patient.

Question 30Radiation Health and Safety

Which statement correctly describes the relationship between milliamperage and the quantity of X-ray photons produced?

  1. Increasing mA decreases the exposure time required for a given density
  2. Increasing mA increases the penetrating power of each photon
  3. Increasing mA increases the number of photons produced per unit time Correct answer.
  4. Increasing mA shifts the beam spectrum toward higher energies

Explanation

Milliamperage controls the tube current, which determines the number of electrons striking the target and therefore the number of X-ray photons produced. It affects quantity, not the energy of individual photons.

Question 31Radiation Health and Safety

Which of the following is the best description of the inverse square law as it applies to dental radiography?

  1. The intensity of radiation is inversely proportional to the distance from the source
  2. The intensity of radiation is directly proportional to the distance from the source
  3. The intensity of radiation is proportional to the square of the distance from the source
  4. The intensity of radiation is inversely proportional to the square of the distance from the source Correct answer.

Explanation

The inverse square law states that radiation intensity decreases with the square of the distance from the source. Doubling the distance reduces the intensity to one quarter of its original value.

Question 32Radiation Health and Safety

A radiographer is about to expose a receptor and notices the patient's lead apron is draped over the patient's shoulders but not covering the lap. What is the most appropriate action?

  1. Reposition the apron to cover the patient's lap and torso before exposing Correct answer.
  2. Remove the apron because it does not affect the image
  3. Proceed with the exposure because the apron is in place
  4. Ask the patient to hold the apron in place during the exposure

Explanation

The lead apron should cover the patient's trunk and lap to shield the gonads and other radiosensitive organs from scatter. Repositioning before exposure ensures the intended protection is achieved.

Question 33Radiation Health and Safety

What is the recommended position of the radiographer relative to the primary beam during an intraoral exposure?

  1. Behind the patient's head, holding the receptor
  2. Directly beside the PID to monitor the patient
  3. At least six feet from the tubehead and out of the primary beam Correct answer.
  4. Behind the patient, within the path of the primary beam

Explanation

The radiographer should stand at least six feet from the tubehead and outside the path of the primary beam to reduce occupational exposure. Standing behind a barrier when available provides additional protection.

Question 34Radiation Health and Safety

A radiographer is evaluating a receptor that appears uniformly fogged with reduced contrast. Which factor is the most likely cause?

  1. Insufficient developing time
  2. Scatter radiation reaching the receptor Correct answer.
  3. Underexposure of the receptor
  4. Use of a receptor holder

Explanation

Scatter radiation that reaches the receptor adds uniform exposure and reduces contrast, producing a fogged appearance. Proper collimation, shielding, and beam restriction help reduce scatter.

Question 35Radiation Health and Safety

Which of the following best explains why a rectangular collimator is preferred over a round collimator for intraoral radiography?

  1. It allows the radiographer to stand closer to the tubehead
  2. It eliminates the need for a lead apron
  3. It reduces the area of patient tissue exposed while still covering the receptor Correct answer.
  4. It increases the kilovoltage delivered to the patient

Explanation

A rectangular collimator matches the shape of the intraoral receptor more closely than a round collimator. This reduces the volume of tissue irradiated and lowers patient dose while still exposing the receptor.

Question 36Radiation Health and Safety

A radiographer wants to reduce occupational exposure during a series of intraoral exposures. Which practice is most effective?

  1. Standing at least six feet from the tubehead and behind a barrier when possible Correct answer.
  2. Increasing the exposure time to reduce the number of retakes
  3. Holding the receptor for the patient to speed the procedure
  4. Using a longer PID to increase the source-to-receptor distance

Explanation

Distance and shielding are the most effective ways to reduce occupational exposure during intraoral radiography. Standing at least six feet away and behind a barrier limits the radiographer's dose.

Question 37Radiation Health and Safety

Which of the following is the correct way to store unexposed intraoral receptors to prevent fog?

  1. In a warm area near the X-ray tubehead
  2. Near the developing solutions for convenience
  3. In direct sunlight to keep them dry
  4. In a cool, dry location shielded from radiation Correct answer.

Explanation

Unexposed receptors should be stored in a cool, dry place shielded from radiation and light to prevent fog. Proper storage preserves receptor sensitivity and image quality.

Question 38Radiation Health and Safety

A patient asks why a lead apron is used when only a small area of the mouth is being imaged. Which explanation is most accurate?

  1. The apron prevents the primary beam from reaching the receptor
  2. The apron reduces the exposure time required
  3. The apron protects the patient from scatter radiation produced in the tissues Correct answer.
  4. The apron increases the contrast of the radiograph

Explanation

Even with a restricted beam, some radiation is scattered within the patient's tissues. The lead apron shields radiosensitive organs such as the gonads and thyroid from this scatter.

Question 39Radiation Health and Safety

Which of the following best describes the purpose of the aluminum filter in the X-ray tubehead?

  1. To absorb low-energy photons that would increase patient dose without contributing to the image Correct answer.
  2. To cool the anode during exposure
  3. To focus the beam toward the receptor
  4. To increase the number of photons produced at the target

Explanation

Aluminum filtration absorbs low-energy photons that would be absorbed by the patient's superficial tissues without reaching the receptor. This reduces patient dose while preserving diagnostic beam quality.

Question 40Radiation Health and Safety

A radiographer notices that the exposure switch must be held down continuously to complete an exposure. Which statement about this type of switch is correct?

  1. It is a timer that automatically ends the exposure
  2. It is a dosimeter that records the exposure
  3. It is a dead-man switch that terminates the exposure if released Correct answer.
  4. It is a collimator control that adjusts beam size

Explanation

A dead-man switch requires continuous pressure and ends the exposure when released, protecting the operator and patient from unintended exposure. This is a required safety feature on dental X-ray units.

Question 41Radiation Health and Safety

Which of the following is an example of a quality control test performed on a dental X-ray unit?

  1. Reviewing the patient's medical history
  2. Scheduling the next recall appointment
  3. Checking the developing solution temperature
  4. Verifying the beam alignment and collimator size Correct answer.

Explanation

Quality control tests include checks of beam alignment, collimation, exposure reproducibility, and filtration. These tests help ensure the unit produces diagnostic images with minimal unnecessary exposure.

Question 42Radiation Health and Safety

A radiographer receives a dosimeter report showing a dose above the investigation level. What is the most appropriate first step?

  1. Reduce the number of radiographs taken for all patients
  2. Ignore the result if the radiographer feels well
  3. Discard the dosimeter and request a new one
  4. Review work practices and the dosimeter report to identify the cause Correct answer.

Explanation

An elevated dosimeter reading should prompt a review of work practices, dosimeter handling, and exposure conditions to identify and correct the cause. This is part of the facility's radiation protection program.

Question 43Radiation Health and Safety

Which statement about the collimator and PID of a dental X-ray unit is correct?

  1. The PID should be pointed at the patient's eye to aid alignment
  2. The collimator should be removed to increase image density
  3. The PID and collimator together restrict the beam to the region of interest Correct answer.
  4. The PID increases the beam diameter at the receptor

Explanation

The collimator and PID work together to restrict the beam and reduce divergence, limiting the exposed tissue to the region of interest. Proper alignment is essential to keep the beam within the receptor area.

Question 44Radiation Health and Safety

Which of the following best explains why the exposure time should be kept as short as diagnostically acceptable?

  1. Shorter exposure time reduces patient dose and motion artifacts Correct answer.
  2. Shorter exposure time increases the receptor's sensitivity
  3. Shorter exposure time eliminates the need for collimation
  4. Shorter exposure time increases the beam's kilovoltage

Explanation

Reducing exposure time lowers the dose delivered to the patient and decreases the chance of movement during exposure. Both benefits support the ALARA principle in dental radiography.

Question 45Radiation Health and Safety

A radiographer is evaluating a periapical image that shows the cone cut, with part of the receptor unexposed. Which correction is most appropriate?

  1. Increase the kilovoltage
  2. Decrease the developing time
  3. Use a larger receptor
  4. Align the PID with the receptor and reposition the patient Correct answer.

Explanation

Cone cutting occurs when the beam is not properly aligned with the receptor, leaving part of it unexposed. Correcting the PID alignment and patient positioning ensures full receptor coverage.

Question 46Radiation Health and Safety

Which of the following is the most appropriate way to reduce patient dose when using a digital intraoral receptor?

  1. Removing the lead apron to speed the procedure
  2. Increasing the exposure time to improve image quality
  3. Using rectangular collimation and proper technique factors Correct answer.
  4. Repeating exposures to ensure a diagnostic image

Explanation

Rectangular collimation and properly selected technique factors minimize the volume of tissue exposed and the dose per exposure. Digital receptors also allow lower exposures than film when the system is optimized.

Question 47Radiation Health and Safety

A patient reports having had a thyroid condition and asks whether the lead collar is necessary. What is the best response?

  1. The collar is only needed for panoramic imaging
  2. The collar is unnecessary because the beam is collimated
  3. The collar should be omitted to improve image contrast
  4. The collar should be used because the thyroid is radiosensitive and shielding reduces dose Correct answer.

Explanation

The thyroid is a radiosensitive organ, and a lead collar reduces scatter dose to it during intraoral exposures. Shielding is appropriate whenever it does not interfere with the diagnostic image.

Question 48Radiation Health and Safety

A radiographer is comparing two techniques for a mandibular molar periapical: one using a 16-inch PID and one using an 8-inch PID with adjusted exposure. Which statement is correct?

  1. The longer PID requires a higher exposure to maintain density
  2. The shorter PID produces less geometric distortion
  3. The shorter PID reduces scatter reaching the receptor
  4. The longer PID reduces beam divergence and lowers patient dose when exposure is adjusted Correct answer.

Explanation

A longer PID reduces beam divergence, so a smaller volume of tissue is irradiated and patient dose is lowered when exposure is adjusted. It also improves image sharpness by reducing magnification.

Question 49Radiation Health and Safety

A radiographer notices that the exposure switch can be activated while the radiographer stands next to the patient without a barrier. Which principle should guide the radiographer's action?

  1. Increase the kilovoltage to shorten exposure time
  2. Ask the patient to hold the switch
  3. Rely on the collimator to limit exposure
  4. Maximize distance and use shielding whenever feasible Correct answer.

Explanation

Distance and shielding are fundamental radiation protection principles that reduce occupational dose. The radiographer should step back at least six feet and use a barrier when available before activating the switch.

Question 50Radiation Health and Safety

Which of the following best explains why a dosimeter should be worn at collar level outside a lead apron for a radiographer who rarely uses a lead apron?

  1. It measures the dose to the hands during receptor placement
  2. It measures the dose to the patient during exposure
  3. It measures the dose to the gonads directly
  4. It measures the dose to the head and neck, which is the most relevant estimate of effective dose Correct answer.

Explanation

A collar-level dosimeter estimates dose to the head and neck, which is used to estimate effective dose when no apron is worn. When an apron is used, additional dosimeters may be needed to estimate whole-body dose.