MJDF Radiology & IRMER

Question 1

What does IRMER 2017 stand for and what does it primarily regulate?

Accepted Answer

Ionising Radiation (Medical Exposure) Regulations 2017 — regulates medical exposures to ionising radiation, including dental radiography

Answer

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.

Question 2

What is the 'ALARP' principle in radiation protection?

Accepted Answer

As Low As Reasonably Practicable — minimising radiation dose while maintaining diagnostic quality

Answer

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.

Question 3

Which radiograph delivers the highest radiation dose to the patient in routine dental practice?

Accepted Answer

Cone beam CT (CBCT)

Answer

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.

Question 4

What is the effective radiation dose of a standard full-mouth periapical series compared to a panoramic radiograph?

Accepted Answer

Full mouth series: ~150–170 µSv; panoramic: ~6–22 µSv (modern systems)

Answer

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.

Question 5

Under IRMER 2017, what responsibility does the 'Operator' have?

Accepted Answer

Practically carries out the exposure — positions the patient and equipment, presses the exposure button, processes the image

Answer

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.

MJDF Part 1 Practice Test

MJDF Part 1 Practice Test

MJDF Radiology & IRMER