Radiology & IRMER Flashcards
6 cards from real MJDF practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Radiology & IRMER flashcards as text
What does IRMER 2017 stand for and what does it primarily regulate?
Answer: Ionising Radiation (Medical Exposure) Regulations 2017 — regulates medical exposures to ionising radiation, including dental radiography
IRMER 2017 is the UK statutory instrument regulating medical (including dental) exposures to ionising radiation, requiring justification, optimisation (ALARP), and dose limitation for all radiographic examinations.
What is the 'ALARP' principle in radiation protection?
Answer: As Low As Reasonably Practicable — minimising radiation dose while maintaining diagnostic quality
ALARP requires that radiation doses be kept as low as is reasonably practicable, balancing the reduction of radiation risk against the practical (cost, effort) measures required to achieve it.
Which radiograph delivers the highest radiation dose to the patient in routine dental practice?
Answer: Cone beam CT (CBCT)
CBCT delivers the highest patient dose in routine dental imaging, ranging from 30 µSv (limited FOV) to over 1,000 µSv (large FOV, high-resolution protocols), depending on the FOV and machine settings.
What is the effective radiation dose of a standard full-mouth periapical series compared to a panoramic radiograph?
Answer: Full mouth series: ~150–170 µSv; panoramic: ~6–22 µSv (modern systems)
A full-mouth periapical series (18 films) typically delivers a higher cumulative dose than a panoramic radiograph; modern digital panoramic systems significantly reduce dose compared to film panoramics.
Under IRMER 2017, what responsibility does the 'Operator' have?
Answer: Practically carries out the exposure — positions the patient and equipment, presses the exposure button, processes the image
The Operator is the person who physically carries out the radiographic exposure under an employer's written procedures; operators must ensure correct positioning, exposure settings, and processing as per protocols.
What is the difference between deterministic and stochastic radiation effects?
Answer: Deterministic effects have a threshold dose (e.g., cataract, erythema); stochastic effects are probabilistic with no threshold (e.g., cancer induction)
Deterministic effects (e.g., cataract, skin reactions) occur above a threshold dose and increase in severity with dose; stochastic effects (e.g., cancer) have no threshold — any dose has a small probability of harm.