Radiology & Radiation Protection Flashcards

What legislation governs radiation protection in the UK dental environment?

Answer: Ionising Radiations Regulations 2017 (IRR17) and Ionising Radiation (Medical Exposure) Regulations 2017 (IR(ME)R 2017)

UK dental radiation is governed by IRR17 (protecting workers and the public) and IR(ME)R 2017 (governing medical exposures of patients). Both must be complied with simultaneously in any dental radiographic practice.

What does ALARP mean in radiation protection?

Answer: As Low As Reasonably Practicable — exposures must be kept as low as reasonably achievable while still providing diagnostic benefit

ALARP (As Low As Reasonably Practicable) is the fundamental principle of radiation protection. Doses must be reduced to the lowest level that still provides adequate diagnostic information, weighing benefit against risk.

What is the role of the 'referral criteria' in dental radiography?

Answer: Evidence-based guidelines (e.g., FGDP Selection Criteria for Dental Radiography) that ensure X-rays are only taken when clinical benefit justifies the radiation risk — not as routine

Referral criteria (selection criteria) ensure radiographs are only prescribed when clinical information gained will positively influence patient management. Routine radiographs without clinical justification are unjustified exposures.

What radiation detector is worn by dental radiographers for personal dose monitoring?

Answer: Thermoluminescent dosimeter (TLD) badge or electronic personal dosimeter (EPD)

Classified workers (those whose annual dose may exceed 3/10 of dose limits) wear TLD badges or EPDs for personal dose monitoring. These track cumulative exposure and must be reviewed regularly.

What is the effective dose from a full mouth periapical series of radiographs (approximately)?

Answer: Approximately 30–100 µSv (microsieverts) depending on technique and equipment

A full periapical series delivers approximately 30–100 µSv effective dose, roughly equivalent to a few days of natural background radiation. Individual periapicals are approximately 1–8 µSv each.

What is the principal risk from low-dose ionising radiation in dental practice?

Answer: Stochastic effects — probabilistic cancer induction and genetic effects with no threshold dose; risk is proportional to cumulative dose

At the low doses used in dentistry, the primary concern is stochastic effects: radiation-induced DNA damage that may (probabilistically) lead to cancer or heritable genetic effects. These have no threshold — risk exists at any dose but is proportionally very small at dental doses.