NDAEB Dental Radiography Safety Questions and Answers 1 — Questions and Answers
Question 1: According to Health Canada's Safety Code 30, what is the primary purpose of using a lead thyroid collar in addition to a lead apron during intraoral radiography?
- To protect the highly radiosensitive thyroid gland from scatter radiation. (Correct answer)
- To reduce the patient's gag reflex during imaging procedures.
- To stabilize the patient's head and prevent movement artifacts.
- To protect the reproductive organs from the primary X-ray beam.
Correct answer: To protect the highly radiosensitive thyroid gland from scatter radiation.
Health Canada's Safety Code 30 emphasizes protecting radiosensitive tissues. The thyroid gland is one of the most radiosensitive organs in the head and neck region. A thyroid collar is specifically designed to absorb scatter radiation that could otherwise expose the gland, which is particularly important for children and young adults.
Question 2: A dental assistant is preparing to take a full mouth series of radiographs on an adult patient. To adhere to the ALARA (As Low As Reasonably Achievable) principle, which of the following actions is most critical?
- Using a rectangular collimator instead of a round one. (Correct answer)
- Doubling the exposure time to ensure a dark image.
- Asking the patient to hold the digital sensor with their finger.
- Setting the kilovoltage (kVp) to the lowest possible machine setting.
Correct answer: Using a rectangular collimator instead of a round one.
Using a rectangular collimator significantly reduces the volume of tissue irradiated by restricting the size of the X-ray beam to be just slightly larger than the receptor. This action can reduce patient radiation dose by up to 60-70% compared to a round collimator and is a key component of the ALARA principle.
Question 3: An operator must stand at a specific position relative to the primary X-ray beam to maximize safety if they must remain in the room. According to Canadian safety guidelines, what is the safest position for the operator?
- At a 45-degree angle to the beam behind the tubehead.
- Directly behind the patient's head.
- Between 90 and 135 degrees to the primary beam. (Correct answer)
- Directly in front of the patient, facing the tubehead.
Correct answer: Between 90 and 135 degrees to the primary beam.
Canadian radiation safety guidelines, including those from the Canadian Dental Association, state that if an operator must remain in the room, they should stand at an angle of 90 to 135 degrees to the primary beam and at least 3 metres away. This area receives the least amount of scatter radiation.
Question 4: In Ontario, the Healing Arts Radiation Protection (HARP) Act governs the use of dental X-ray equipment. Who is ultimately responsible for ensuring that all X-ray operators, including dental assistants, are properly qualified and that the equipment is maintained?
- The individual dental assistant.
- The provincial government inspector.
- The designated Radiation Protection Officer (RPO), who must be a dentist. (Correct answer)
- The equipment manufacturer.
Correct answer: The designated Radiation Protection Officer (RPO), who must be a dentist.
The HARP Act requires the owner of an X-ray machine to designate a Radiation Protection Officer (RPO), who must be a dentist in a dental facility. The RPO is responsible for establishing and maintaining safety procedures, ensuring equipment meets standards, and verifying that all operators are qualified according to the Act.
Question 5: Which of the following is NOT a requirement for a dental assistant to legally operate radiographic equipment in Canada?
- Successful completion of a recognized course in dental radiography safety.
- Operating under the general supervision of a licensed dentist.
- Personal ownership of a dosimeter to measure occupational exposure. (Correct answer)
- Adherence to the principles of ALARA and Safety Code 30.
Correct answer: Personal ownership of a dosimeter to measure occupational exposure.
While the use of personal dosimeters is strongly advised and may be required in certain circumstances (e.g., for pregnant staff or upon request), personal ownership and mandatory continuous use for all operators is not a universal legal requirement under regulations like the HARP Act. The other options are all fundamental requirements for dental assistants taking radiographs in Canada.
Question 6: A pregnant patient requires an essential periapical radiograph for an emergency diagnosis. What is the most appropriate safety protocol to follow in this scenario?
- Postpone the radiograph until after the patient has given birth.
- Proceed with the radiograph using a lead apron and thyroid collar. (Correct answer)
- Ask the patient to sign a waiver releasing the clinic from liability.
- Take the radiograph but use two lead aprons for extra protection.
Correct answer: Proceed with the radiograph using a lead apron and thyroid collar.
When radiographs are essential for diagnosis during pregnancy, the procedure should not be delayed. With modern equipment and proper safety protocols, such as using a lead apron and thyroid collar, the radiation dose to the fetus is negligible. The goal is to obtain necessary diagnostic information while ensuring maximum protection.
NDAEB Dental Radiography Safety Questions and Answers 1
According to Health Canada's Safety Code 30, what is the primary purpose of using a lead thyroid collar in addition to a lead apron during intraoral radiography?