DRC Radiation Protection & Compliance 2 — Questions and Answers
Question 1: Which regulatory body sets the occupational dose limit of 50 mSv per year for radiation workers in the US?
- FDA
- NCRP
- NRC (Correct answer)
- ADA
Correct answer: NRC
The Nuclear Regulatory Commission (NRC) sets the annual occupational effective dose limit of 50 mSv (5 rem) for radiation workers.
Question 2: What is the recommended ALARA principle in dental radiography?
- Use the highest kVp settings available
- Keep radiation exposure As Low As Reasonably Achievable (Correct answer)
- Always use the fastest film speed
- Limit radiographs to once per year
Correct answer: Keep radiation exposure As Low As Reasonably Achievable
ALARA stands for As Low As Reasonably Achievable and guides practitioners to minimize patient and operator exposure without compromising diagnostic quality.
Question 3: A pregnant dental hygienist's fetal dose limit per gestational period is:
- 50 mSv
- 5 mSv
- 1 mSv (Correct answer)
- 0.5 mSv
Correct answer: 1 mSv
The NCRP recommends a fetal dose equivalent limit of 1 mSv (0.1 rem) during the entire gestational period for occupationally exposed workers.
Question 4: What type of dosimeter measures cumulative radiation exposure over time and is worn by dental personnel?
- Geiger-Müller counter
- Ionization chamber survey meter
- Thermoluminescent dosimeter (TLD) (Correct answer)
- Scintillation detector
Correct answer: Thermoluminescent dosimeter (TLD)
Thermoluminescent dosimeters (TLDs) and optically stimulated luminescence (OSL) badges are worn by personnel to monitor cumulative occupational exposure.
Question 5: The primary purpose of a lead apron during dental radiography is to:
- Reduce scatter radiation to the patient's thyroid
- Protect the patient's radiosensitive organs from primary and scatter radiation (Correct answer)
- Improve image contrast
- Reduce the need for collimation
Correct answer: Protect the patient's radiosensitive organs from primary and scatter radiation
Lead aprons shield the patient's gonads, bone marrow, and other radiosensitive organs from both primary and scattered radiation during exposures.
Question 6: Which of the following is NOT a method used to reduce patient radiation dose in dental radiography?
- Using E or F-speed film
- Using rectangular collimation
- Increasing exposure time (Correct answer)
- Using digital sensors
Correct answer: Increasing exposure time
Increasing exposure time increases patient dose; dose reduction strategies include faster image receptors, rectangular collimation, and higher kVp settings.
Question 7: How far should the operator stand from the X-ray tube head during an exposure if no protective barrier is available?
- At least 1 meter (3 feet)
- At least 2 meters (6 feet) (Correct answer)
- At least 3 meters (10 feet)
- At least 6 meters (20 feet)
Correct answer: At least 2 meters (6 feet)
If no protective barrier is available, the operator should stand at least 6 feet (2 meters) from the patient and outside the primary beam path.
DRC Radiation Protection & Compliance 2
Which regulatory body sets the occupational dose limit of 50 mSv per year for radiation workers in the US?