How do you limit the dose to patients and yourselves?

Question 1

What do we do when a new patient comes in?

Answer 1

Clinical examintion, then if necessary take a radiograph

Also check if a radiograph has recently been taken.

Question 2

What is the FGDP?

Answer 2

the FGDP is the Faculty of General Dental Practice (UK)

there are a selection criteria guidelines that help whether a radiograph is needed.

Question 3

If you decide to take a radiograph what principle do you follow?

Answer 3

ALARP principle (as low as reasonably practicable).

Question 4

How do you put the ALARP principle into practice?

Answer 4

Equipment - make sure it is working and well maintained and is tested and quality insured, make sure it doesn’t malfunction

Staff training - trained how to use the equipment and use it with good technique reduces doing repeated radiographs.

Reduce exposure factors

Question 5

How is the dose effected when the kVp is increased?

Answer 5

By increasing the kVp you lower the dose because the x-ray photons have higher energy, more likely to pass through the patient, but we reduce the contrast, so important to find a balance between dose and contrast.

Question 5

How can we optimise a dose and get a clear image?

Answer 5

By using a digital image, uses a lower dose and it is more sensitive to the x-rays.

The majority of dental practices use digital imaging.

digital imaging has a broader exposure latitude so if you accidentally increase the time or mA it won’t affect the image as much.

Question 6

How does collimation optimise the dose of the patient?

Answer 6

Collimation is used for intraoral image, the tube matches the shape of the film. So there are no unnecessary areas exposed to x-rays, reducing the dose

Question 7

How can we optimise the dose when taking an extraoral radiograph?

Answer 7

using field limitation settings.

Question 8

how else can we reduce the dose?

Answer 8

Protecting the patient by giving them a thyroid shield and lead apron. This protects them from scattered radiation.

not necessary in dental radiography but should be given if the thyroid is in the primary beam.

Controlled area -
“Within the primary x-ray beam until it has been sufficiently attenuated by distance or shielding”
“Within 1.5 m of the x-ray tube and the patient, in any other direction

Question 9

When is the thyroid in the primary beam and so would need a thyroid shield?

Answer 9

upper occlusal radiography
bisected angle technique

Question 10

why do we not do dental radiographs on pregnant women?

Answer 10

Because of the emotive nature of radiography during pregnancy, the patient could be given the option of delaying the radiography.”

Risk to the unborn child is negligible. It is safe to take radiographs on pregnant women, however some women maybe apprehensive.

Question 11

how to reduce radiation exposure for staff?

Answer 11

limit the time
increase the distance - The inverse square law
using shielding - in dental practice may leave the room

Question 12

what is a classified worker?

Answer 12

If an individual is expected to receive an annual dose which exceeds 3/10 of any annual dose limit then they must be registered as a “classified worker”

Subjected to more thorough dose monitoring and medical surveillance

Question 13

What is the annual limit of effective does in millisieverts?

Answer 13

20 mSv

Question 14

what are the two key legislations regarding ionisation?

Answer 14

The Ionising Radiation Regulations 2017 (IRR 17)

The Ionising Radiation (Medical Exposure) Regulations 2017 (IRMER 17)

Question 15

What are the Ionising Radiation Regulations 2017 (IRR 17)?

Answer 15

Concerned principally with safety of workers and general public

Enforced by Health and safety executives.

Question 16

what is The Ionising Radiation (Medical Exposure) Regulations 2017 (IRMER 17)?

Answer 16

Concerned with patient safety

Enforced by:
Care Quality Commission in England
Healthcare Inspectorate Wales
Healthcare Improvement Scotland
Regulation and Quality Improvement Authority in Northern Ireland.

Question 17

How does the IRR effect employers?

Answer 17

Has responsibility to provide a safe working environment for staff and other persons who may enter the premises

Question 18

What is the radiation protection advisor (RPA)?

Answer 18

An external member to ensure we are compliant with the legislation.

Question 19

what are the local rules?

Answer 19

local rules are a set of rules for the controlled area which is set by the RPA.

Question 20

What is the radiation protection supervisor (RPS)?

Answer 20

An RPS must be appointed by the employer to make sure that the local rules are being complied with

An appropriate appointee would be a dentist or dental care professional

They should be closely involved with radiography and received appropriate training

Question 21

What are the key features of the IRMER legislation?

Answer 21

These regulations protect patients undergoing diagnosis or therapy, medical research studies or medico-legal procedures which involve exposure to ionising radiation

All medical exposures must be justified

The object of this legislation is to restrict the dose to the patient to be as low as possible and still achieve the desired diagnostic or therapeutic result (ALARP)

Dose limits do not apply to patients

Question 22

What roles does the IRMER involve?

Answer 22

The employer

The referrer

The practitioner

The operator

The medical physics expert (MPE

Question 23

How does the IRMER effect employers?

Answer 23

Responsible for setting up a framework for the radiation protection of patients

Identification of who is entitled to act as a referrer, practitioner, operator

Ensure that practitioners and operators are adequately trained

Appoint an MPE

Establishment of referral criteria to ensure exposures are justified

Ensure patient doses are optimised (ALARA)

Adopt diagnostic reference levels (DRLs) in consultation with the MPE

Question 24

How does the IRMER effect the referrer?

Answer 24

The referrer provides sufficient clinical information to allow the exposure to be justified.

Question 25

How does the IRMER effect the practitioner?

Answer 25

justifies the exposure

Question 26

How does the IRMER effect the operator?

Answer 26

Responsible for all practical aspects associated with performing the exposure.
Reporting of the radiographs is also an operator role

Question 27

What are the medical physics experts?

Answer 27

External expert:

The MPE is a state-registered clinical scientist

Give advise on optimisation of patient dose

Under IRMER 2000 an MPE had to be involved medical exposures
Under IRMER 2017 an MPE must be formally appointed and must be recognised by the state

The RPA is often also able to act as the MPE

Question 28

what are Diagnostic Reference Levels?

Answer 28

The Regulations require the employer to set DRLs

A DRL is a dose level for typical examinations on standard sized patients

In other words a DRL is reference dose for common x-ray examinations

They would not normally be expected to be exceeded without good reason

In consultation with an MPE the employer must adopt DRLs for local use having regard to national DRLs where available.