ORE Part 1 Radiology & Radiation Protection 3 — Questions and Answers
Question 1: What does IR(ME)R 2017 define as the roles of 'referrer', 'practitioner', and 'operator' in dental radiography?
- Referrer: justifies clinical need for the X-ray; Practitioner: takes clinical responsibility by justifying the specific exposure; Operator: performs the practical procedure and optimises the technique (Correct answer)
- All three roles can only be performed by a dentist
- Operator and practitioner are always the same person
- Referrer must be a radiologist in all cases
Correct answer: Referrer: justifies clinical need for the X-ray; Practitioner: takes clinical responsibility by justifying the specific exposure; Operator: performs the practical procedure and optimises the technique
IR(ME)R defines: the Referrer requests the X-ray (usually dentist or other clinician), the Practitioner justifies and authorises the specific exposure, and the Operator sets up and performs the exposure. One person may hold multiple roles.
Question 2: What is the typical kVp range used for intraoral dental radiography?
- 60–70 kVp (higher kVp reduces patient dose but increases scatter) (Correct answer)
- 30 kVp
- 120–140 kVp (used for CT)
- 15 kVp (used for mammography)
Correct answer: 60–70 kVp (higher kVp reduces patient dose but increases scatter)
Intraoral dental radiography typically uses 60–70 kVp. Higher kVp produces more penetrating (harder) X-rays, reducing patient dose through less photoelectric absorption, while increasing scatter. Rectangular collimation at this kVp greatly reduces dose.
Question 3: What is rectangular collimation and why is it preferred in dental radiography?
- A rectangular lead collimator limiting the X-ray beam to match the size of the intraoral film/sensor — reduces patient dose by approximately 60–70% compared to circular collimation (Correct answer)
- A method of aligning the tube head only
- A type of sensor used in digital radiography
- A term for rectangular film packaging
Correct answer: A rectangular lead collimator limiting the X-ray beam to match the size of the intraoral film/sensor — reduces patient dose by approximately 60–70% compared to circular collimation
Rectangular collimation restricts the primary beam to closely match the film/sensor dimensions, minimising exposure of surrounding tissues. It reduces effective patient dose by approximately 60–70% compared to circular/round collimators.
Question 4: What is a 'periapical index' (PAI) and how is it used?
- A standardised radiographic scoring system (1–5) for assessing periapical pathology severity on radiographs — used in research and clinical outcome assessment of endodontic treatment (Correct answer)
- A clinical index for assessing gingival inflammation
- A scoring system for caries severity on radiographs
- A measurement of root length on radiographs
Correct answer: A standardised radiographic scoring system (1–5) for assessing periapical pathology severity on radiographs — used in research and clinical outcome assessment of endodontic treatment
The Periapical Index (Ørstavik 1986) scores the periapical appearance on a 1–5 scale: 1 = normal bone structure; 5 = severe periodontitis with features of systemic spread. Used to assess endodontic treatment success.
Question 5: What is the 'bitewing' radiograph specifically used for?
- Detecting interproximal caries and monitoring alveolar bone levels in posterior teeth — the standard caries detection radiograph (Correct answer)
- Assessing root morphology
- Diagnosing periapical disease
- Evaluating salivary gland calculi
Correct answer: Detecting interproximal caries and monitoring alveolar bone levels in posterior teeth — the standard caries detection radiograph
Bitewing radiographs show the crowns and coronal third of roots of both upper and lower posterior teeth simultaneously, making them the most sensitive and standard method for detecting early approximal caries and monitoring posterior alveolar bone.
Question 6: What hazard does a pacemaker present in the dental environment from radiation?
- Modern pacemakers are not adversely affected by dental X-rays — no special precautions required for dental radiography in pacemaker patients (Correct answer)
- Dental X-rays can reset or damage pacemakers
- Lead apron must be placed over the chest during all dental X-rays for pacemaker patients
- Pacemaker patients cannot receive dental X-rays
Correct answer: Modern pacemakers are not adversely affected by dental X-rays — no special precautions required for dental radiography in pacemaker patients
Dental X-ray doses are too low to affect modern pacemakers. Older concerns related to electromagnetic interference from X-ray equipment are not relevant at dental doses. No specific X-ray precautions are needed for pacemaker patients.
ORE Part 1 Radiology & Radiation Protection 3
What does IR(ME)R 2017 define as the roles of 'referrer', 'practitioner', and 'operator' in dental radiography?