Radiation Safety

Question 1

What are the basic principles of the ICRP system?

International Commission for Radiological Protection (ICRP)

Answer 1

• Justified = The benefits must outweigh the risk of the radiation exposure.
• Optimised = Keep exposure levels As low as Reasonably Practicable.
• Limited = Radiation dose limits ensure no person receives an unacceptable level of radiation exposure.

Question 2

What are the two laws regarding radiation in th UK?

what act are they under?

Answer 2

The important Legislation in diagnostic radiology is:
* Ionising Radiations Regulations 2017 (IRR17)
* Ionising Radiation (Medical Exposure) Regulations 2017 (IRMER17)
These are enacted under the Health and Safety at Work Act

Question 3

What does IRR17 deal with?

Answer 3

with occupational exposure of staff and exposure of the general public

Question 4

What is IRR17 enforced by?

Answer 4

Health and Safety Executive (HSE)

The employer is responsible for putting in place arrangements for compliance
Employees are responsible for following the safety arrangements

Question 5

What are the implications of IRR17 for dentists?

private and NHS

Answer 5

NHS: NHS is responsible for compliance as the employer
Private practice: Owner(s) responsible as the employer

Question 6

What is an RPA?

Answer 6

A Radiation Protection Adviser (RPA) is a person meeting HSE requirements to advise on radiation safety

Consulted for safety in design, equipment checks, and risk assessments.

Question 7

What is the controlled area distance for intra-oral x-rays?

Answer 7

1.5m from x ray tube and within the primary bean

Question 8

What is the controlled area distance for cone beam cts?

Answer 8

entire room is controlled area

Question 9

When is signage required?

Answer 9

Where the entire room is a controlled area, or when the entrance leads directly into the controlled area,

Question 10

What are the annual radiation dose limits for radiation workers and members of the public?

Answer 10

• Radiation Workers: Whole body limit of 6mSv/year
• Members of the public: Whole body limit of 1mSv/year
• (dental staff dose levels should be far below the dose limits)

Question 11

What does IRMER17 deal with?

Answer 11

with exposure of patients (and some other groups)

Question 12

Who is IRMER17 enforced by?

from when

Answer 12

Healthcare Improvement Scotland
december 2018

Question 13

Who does IRMER17 apply to?

Answer 13

Patients as part of diagnosis or treatment
Health Screening
Research
Asymptomatic individuals
Carers and Comforters
Individuals undergoing non-medical imaging using medical equipment

Question 14

Who are carers and comforters?

Answer 14

individuals who are ‘knowingly and willingly’ exposed to radiation to support and comfort those undergoing exposure - these are not employees and are usually a relative or a friend, such as a parent.

Question 15

When is imaging used non-medically?

Answer 15

• health assessment for employment purposes
• health assessment for immigration purposes
• health assessment for insurance purposes
• radiological age assessment
• identification of concealed objects within the body.

Question 16

Who is responsiblle for putting in place arrangements for compliance?

under IRMER17

Answer 16

the employer

employees are responsible for following these arrangements

Question 17

What do employers have to show to show what procedures they’re going to comply with?

Answer 17

patient identification
entitlement of staff
information provided to patients

Question 18

What are the types of duty holders and what is their role?

Answer 18

• Referrer = Responsible for providing enough information for patient identification and to enable justification.
• Practitioner = Decides if the exposure is justified and ensures doses are ALARP.
• Operator = Select the right equipment, follow the employer’s procedures and ensure the request is justified and authorised.
  
  • In dentistry, a dentist will perform all these roles.

Question 19

What is the basic framework for carrying out medical exposures?

Answer 19

• Referral for imaging Requested by a Referrer
• The examination must be justified by a Practitioner who may also authorise it
• The examination may be authorised and will be carried out by an Operator
• The image is assessed and reported by an Operator
• The image and report are provided to the Referrer

Question 20

When can an exam not legally proceed?

Answer 20

unless justification process is complete

Question 21

What is a clinical evaluation?

who ensures it

Answer 21

• The Employer must have procedures to ensure that a clinical evaluation of the outcome of each medical exposure is recorded
  – Procedures for in-department reporting
  – Procedure for images sent externally for reporting.
• An exposure cannot be Justified if it is known a Clinical Evaluation will not be performe

Question 22

What is justification?

Answer 22

This must take into account the objectives of the exposure and the benefits and risks to the individual, as well as the benefits and risks of available alternative techniques.

Question 23

What is optimisation?

who is responsible for it

Answer 23

IRMER17 requires that all exposures are optimised.
This means that exposures are as low as reasonably practicable, consistent with the intended purpose
This is a responsibility of both the Practitioner and the Operator

ALARP

Question 24

Who is a medical physics expert (MPE)?

Answer 24

In NHS GG&C, Health Physics MPEs provide advice on exposure factors and equipment-related matters

Question 25

What is the quality assurance of radiation equipment?

what do the regulations specifiy?

Answer 25

The regulations specify that radiation equipment should be regularly tested to ensure it is working correctly and delivering the expected dose level.

Tests are normally split into:
* Routine local tests, carried out by local staff who normally operate the equipment, and;
* Physics tests, carried out every 1 to 3 years by specialist staff

National guidelines suggest what tests should be carried out

Question 26

What are diagnostic reference levels?

Answer 26

• DLRs are guideline dose levels for standard sized patients - they can be used as a comparison value to decide whether your exposure levels are appropriate.
• Some equipment, such as CBCT or panoramic unit, displays a ‘dose indicator’ following an exposure - these can be compared against the DRLs.