NDAEB Dental Radiography Safety 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?

Accepted Answer

To protect the highly radiosensitive thyroid gland from scatter radiation.

Answer

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?

Accepted Answer

Using a rectangular collimator instead of a round one.

Answer

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?

Accepted Answer

Between 90 and 135 degrees to the primary beam.

Answer

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?

Accepted Answer

The designated Radiation Protection Officer (RPO), who must be a dentist.

Answer

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?

Accepted Answer

Personal ownership of a dosimeter to measure occupational exposure.

Answer

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.

(NDAEB) National Dental Assisting Examination Board Practice Test

(NDAEB) National Dental Assisting Examination Board Practice Test

NDAEB Dental Radiography Safety Questions and Answers