UUS Practice Tests⌕ Search
Dental Assisting · RHS

DANB Radiation Health and Safety Examination Practice Test

The DANB Radiation Health and Safety Examination (RHS) concerns safe dental radiography and the science behind producing diagnostic images. Relevant knowledge includes radiation exposure, image receptors, image quality, conventional film processing, digital imaging, and measures that reduce unnecessary exposure to patients and dental personnel.

Exam overview

Exam providerDental Assisting National Board
Exam codeRHS
CategoryDental Assisting

About the DANB Radiation Health and Safety Examination Exam

RHS-related practice draws on the ability to connect exposure settings with x-ray production and resulting image characteristics. It also involves recognizing how receptor response and processing conditions affect image quality, including the roles of phosphor storage plates and chemical developer. Radiation safety concepts include ionizing radiation’s effects on tissue, appropriate protective measures, and clinical judgment when radiographs are needed for patients with special considerations. Quality-control tasks may involve interpreting a stepwedge test and identifying changes that can compromise imaging performance. These concepts support dental assisting work such as preparing patients and equipment, following radiation-protection procedures, and noticing image or equipment problems that may require correction before the next exposure.

Sample Practice Questions

Review a selection from this exam's published US Practice Tests practice bank.

Question 1

Which change to an intraoral x-ray unit’s technique settings generally increases the number of x-ray photons produced, when other factors remain unchanged?

  1. AIncreasing milliamperage
  2. BDecreasing exposure time
  3. CReducing kilovoltage peak
  4. DIncreasing source-to-receptor distance
Show answerCorrect answer: A

Milliamperage controls the rate of electron flow across the tube and therefore the quantity of x-rays produced. Increasing it generally increases photon quantity; the other choices do not do so under the stated conditions.

Question 2

A patient is pregnant and needs a dental radiograph that is clinically necessary. Which approach is generally appropriate?

  1. AAvoid all dental radiographs for the entire pregnancy
  2. BTake the image only if clinically justified, using appropriate radiation-protection practices
  3. CDouble the exposure time to ensure a diagnostic image on the first attempt
  4. DUse a higher tube voltage to eliminate radiation reaching the fetus
Show answerCorrect answer: B

Pregnancy does not automatically prohibit a clinically necessary dental radiograph. The decision should be based on clinical need, with appropriate technique and radiation-protection measures to keep exposure as low as reasonably achievable.

Question 3

What is the main purpose of a stepwedge in a quality-control test of a dental x-ray imaging system?

  1. ATo evaluate whether image density or receptor response changes consistently across known thicknesses
  2. BTo measure the operator’s occupational dose directly
  3. CTo locate the focal spot inside the tube housing
  4. DTo determine the patient’s body mass
Show answerCorrect answer: A

A stepwedge provides areas of progressively different thickness. The resulting image can help assess the consistency of image density or receptor response as part of quality control.

Question 4

A developer solution used for conventional film processing has become depleted. What is a likely effect on films processed in it?

  1. AImages may appear too light because development is inadequate
  2. BImages will always show a mirrored lead-foil pattern
  3. CThe film base will become completely transparent before exposure
  4. DThe image will gain sharpness because less silver is developed
Show answerCorrect answer: A

Depleted developer may not reduce enough exposed silver halide to metallic silver, producing films that are lighter than expected. Processing solutions should be maintained and replaced according to the manufacturer's instructions and established quality-control procedures.

Question 5

What does a phosphor storage plate do in a computed radiography system?

  1. AStores a latent image after x-ray exposure that is later read by a scanner
  2. BConverts x-rays directly into a live monitor image during exposure
  3. CBlocks scattered radiation before it reaches the patient
  4. DMeasures the temperature of the x-ray tubehead
Show answerCorrect answer: A

A photostimulable phosphor storage plate retains a latent image after exposure. A dedicated reader scans the plate with a laser and converts the stored signal into a digital image.

Question 6

A dental image appears too light, and the exposure indicator suggests that the receptor received less radiation than the system's target range. What is a reasonable first step?

  1. AReview positioning and exposure selection, then follow the system's guidance before considering a retake
  2. BImmediately repeat the exposure at the highest available setting
  3. CIncrease monitor brightness and assume the receptor exposure was adequate
  4. DDisable the exposure indicator for future images
Show answerCorrect answer: A

An exposure indicator can help identify whether the receptor exposure was outside the system's target range, but it should be interpreted with image quality and clinical context. Review technique and system guidance rather than reflexively increasing exposure or repeating the image.

Question 7

What is the main biological significance of ionizing radiation interacting with water molecules in tissue?

  1. AIt can produce reactive free radicals that may damage cellular molecules
  2. BIt permanently increases the calcium content of bone
  3. CIt prevents all cellular repair processes
  4. DIt converts tissue oxygen directly into visible light
Show answerCorrect answer: A

Radiation can ionize water and generate reactive free radicals. These molecules may damage DNA and other cellular components, although cells also have repair mechanisms and biological outcomes vary.

How to use this practice test

Access is free. The practice session presents up to 20 randomly selected questions from the 50-question RHS bank. After completing the session, review the results to identify concepts to revisit, such as exposure settings, receptor technology, image quality, film processing, or radiation protection.

Preparation tips

  • Relate changes in kVp, mA, and exposure time to photon production and likely effects on image characteristics.
  • Compare conventional film, computed radiography storage plates, and digital receptors; note how each captures or processes an image.
  • Review how depleted developer and accidental light exposure can affect conventional film, and connect each problem to its likely image appearance.
  • Practice explaining the purpose of stepwedge testing and how it can help assess consistency in a dental imaging system.
  • For radiation-safety scenarios, distinguish protective measures from the clinical decision to obtain a necessary radiograph.
Official sourceOfficial exam page ↗Official exam guide ↗