DANB CDA Radiation Health and Safety — Questions and Answers
Question 1: What is the ALARA principle in dental radiography?
- As Low As Reasonably Achievable — minimizing radiation exposure (Correct answer)
- Always Limit And Reduce Applications
- Appropriate Levels for All Radiographic Activities
- Applying Low-dose Adjustments for Radiographic Accuracy
Correct answer: As Low As Reasonably Achievable — minimizing radiation exposure
ALARA stands for As Low As Reasonably Achievable, a guiding principle requiring that radiation exposure be kept as minimal as possible while still obtaining diagnostic-quality images.
Question 2: What is the maximum permissible dose (MPD) of radiation for occupationally exposed dental workers per year?
- 50 mSv (5 rem) (Correct answer)
- 100 mSv (10 rem)
- 25 mSv (2.5 rem)
- 10 mSv (1 rem)
Correct answer: 50 mSv (5 rem)
The annual maximum permissible dose for occupationally exposed workers is 50 mSv (5 rem) for the whole body, as established by radiation safety guidelines.
Question 3: Which type of radiation is most harmful to dental patients during radiographic procedures?
- Scatter radiation (Correct answer)
- Useful beam radiation
- Secondary radiation
- Leakage radiation
Correct answer: Scatter radiation
Scatter radiation, produced when the primary beam interacts with matter (the patient's tissues), is the most significant source of radiation exposure during dental radiography because it travels in all directions.
Question 4: What is the purpose of a lead apron during dental radiography?
- To protect radiosensitive organs from unnecessary radiation exposure (Correct answer)
- To stabilize the patient during imaging
- To improve image quality
- To reduce scatter radiation to the operator
Correct answer: To protect radiosensitive organs from unnecessary radiation exposure
Lead aprons shield radiosensitive organs such as the thyroid, gonads, and bone marrow from unnecessary radiation exposure during dental radiographic procedures.
Question 5: What is the recommended position for the dental assistant during X-ray exposure?
- At least 6 feet away from the source and behind a barrier or at a 90-135 degree angle (Correct answer)
- Directly behind the patient
- Holding the film in the patient's mouth
- Standing next to the X-ray unit
Correct answer: At least 6 feet away from the source and behind a barrier or at a 90-135 degree angle
The operator should stand at least 6 feet away from the X-ray source and position themselves at a 90-135 degree angle to the primary beam, or behind a protective barrier.
Question 6: What type of dosimeter is commonly used to monitor radiation exposure for dental professionals?
- Film badge or optically stimulated luminescence (OSL) dosimeter (Correct answer)
- Geiger counter
- Scintillation detector
- Ionization chamber
Correct answer: Film badge or optically stimulated luminescence (OSL) dosimeter
Film badges and OSL dosimeters are the most common personal monitoring devices worn by dental professionals to track cumulative radiation exposure over time.
DANB CDA Radiation Health and Safety
What is the ALARA principle in dental radiography?