The two main pieces of legislation are:

  • IRMER 2000: deals with exposure to patients for medical procedures
  • IRR 99: deals with exposure to employees and the public

(Please note: There is a new IRR legislation which will come into effect from February 2018)

For Nuclear Imaging, there is specialised legislation:

  • MARS 78: deals with administration of radioactive substances. Governs individuals.
  • RSA 93: deals with storage and disposal of radioactive substances. Governs institutions.
  • RM(RT)R 2001: deals with transport of radioactive substances

The Ionising Radiation (Medical Exposure) Regulations (2000) (IRMER 2000)

Governs all medical exposures to patients.

  • Justification
  • Optimisation
  • Clinical audit
  • Training
  • Research exposure
  • Medico-legal exposure
  • Accidental and unintended dose 'incidents'
    • Need to minimise the possibilities of incidents occurring
    • Includes cases of operator or procedural failure. Does not include unintended doses due to equipment failure as these are covered by the IRR99

**** The main mantra of IRMER is ALARP: ****

As Low As Reasonably Practical

Diagnostic Reference Levels (DRLs)

Gives guideline of doses, not legal limit (there is no limit for patients but doses should be as low as possible)

Radiograph ESD per radiograph (mGy)
Skull AP
Skull lateral
Chest PA
Chest lateral
Thoracic spine AP
Thoracic spine lateral
Lumbar spine AP
Lumbar spine lateral
Lumbar spine LSJ
Abdomen AP
Pelvis AP

Roles and responsibilities


  • Health care profession entitled in accordance with employer's and local procedures to request and refer individuals for medical exposure
  • Required to supply practitioner with sufficient medical information


  • Required to justify all medical exposures e.g. person who vets requests
  • Can be the radiologist or radiographer


  • Carries out and optimises the medical exposure
  • Includes radiographer pressing the exposure button and technician performing annual quality assurance tests
  • May have responsibility for authorising exposures under written guidance from a practitioner e.g. radiographers in walk in chest x-ray lists can justify AND carry out procedure, i.e. practitioner and operator
  • Responsible for optimisation (ALARP)


  • Implements IRMER and allocates individuals to roles
  • Provide written procedures and protocols
  • Ensure staff are appropriately trained
  • Respond where an incident has occurred

Medical Physics Expert

  • Involved in quality assurance of equipment
  • Consults on optimisation and on matters of radiation protection


  • Referrer doesn't need to justify procedure
  • Practioner justifies exposure
  • Operator optimises exposure, ensures ALARP followed, and operates image intensifier in fluroscopy (may also be practioner)


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Ionising Radiation Regulations 1999 (IRR99)

Made under the Health and Safety at Work Act 1974 and designed to minimise radiation exposure to employees and members of the public. They are enforced by the Health and Safety Executive (HSE)

  • Designed to ensure exposure to workers and members of the public follows ALARP
  • Final responsibility for radiation safety lies first and foremost with the employer

There is new IRR legislation that will come into effect from February 2018. The main changes will be the introduction of new weighting factors and the decrease of the equivalent dose limit to the lens from 150 mSv to 20 mSv in a year.

Roles and Responsibilities

Radiation protection advisor

  • Usually an expert physicist and should be trained in the use of radiation and have thorough
  • knowledge of the associated hazards and their control
  • Must have a certificate of competence issued by a body recognised by the HSE
  • Doesn't have any responsibility for radiation safety
  • Advises on:
    • Identification and designation of controlled and supervised areas
    • Calibration of monitoring equipment
    • Risk assessments
    • Drawing up of local rules and contingency plans
    • Quality assurance programmes

Radiation protection supervisor

  • Appointed by employer
  • Ensures local rules are being complied with
  • Must known what to do in an emergency
  • Must always be present on site


  • Not knowingly expose themselves or others to ionising radiation to a degree that is greater than necessary
  • Make full and proper use of Personal Protective Equipment and report any defects in it
  • Inform the employer about suspected incidents

Prior risk assessment

  • This is mandatory before stating a new activity involving ionising radiation
  • Identify hazards
  • Decide who may be harmed and how
  • Evaluate the risks and decide on precautions
  • Record your findings and implement them
  • Review your assessment and update if necessary

Dose limits per year

To limit stochastic effects the effective dose limits are:

Radiation workers > 18 yo 20 mSv
Members of the public 1 mSv
Radiation workers < 18 yo

6 mSv

i.e. 3/10 of adult dose

Dose limit to abdomen of person of reproductive capacity 13 mSv in any consecutive 3 months
Comforters and carers 5 mSv
Any other person / member of public (fetus counts as member of the public) 1 mSv
Dose to fetus of pregnant employees 1 mSv for remainder of pregnancy


To prevent deterministic effects the equivalent dose limits are:

Lens of the eye 150 mSv (20 mSv in new IRR from February 2018)
Hands, forearms, feet and ankle 500 mSv
Skin 500 mSv

Classified workers

This is anyone who is likely to receive:

  • Effective dose of 6 mSv in a year (3/10 of dose limit)
  • Equivalent dose of greater than 3/10 of any dose limit i.e.
    • > 45 mSv/yr to lens
    • > 150 mSv/yr to skin or extremities

Classified workers must:

  • Must have a medical examination before being designated
  • Must have periodic review of health at least once a year
  • Must be at least 18 years old
  • Records of doses received by classified workers must be kept for at least 50 years

Designation of special areas

Controlled areas

  • Any person working in the area is likely to receive an effective dose of > 6 mSv or equivalent dose of > 3/10 of any relevant dose limit
  • Any person who enters or works in area must follow special procedures to restrict significant exposure

Supervised area

  • Required if anyone working in the area is likely to receive a dose > 1 mSv/yr or an equivalent dose of > 1/10 of any relevant dose limit (i.e. more than the dose limits for the general public)

Reporting overexposure

When caused by equipment failure the following overexposures must be reported to the Health Safety Executive (HSE):

Investigation Intended dose multiplying factor
Fluoroscopic procedure with contrast agents
CT scans
Interventional procedures
1.5 x
10 x
Skull, dental and extremity x-rays
20 x

Nuclear medicine department

Medicine (Administration of Radioactive Substances) Regulations 1978 (MARS78)

  • Regulates administration of a radioactive substance
  • Do not apply to substances that are naturally radioactive or administered for properties other than their radioactivity
  • ARSAC certificates are granted to medical practitioners directly involved in nuclear medicine and identify all procedures that the individual is able to carry out. The ARSAC certificate holder can assign suitably trained people to actually administer the radioactive substances
  • Certificates are valid for 5 years

Radioactive Substances Act 1993 (RSA93)

  • Governs storage and safe disposal of radioactive materials
  • Imposes requirements for traceability and record keeping and contamination monitoring
  • Regulated by the Environment Agency
  • Registration certificates are awarded to the sites of work, not individuals

Radioactive Material (Road Transport) (Great Britain) Regulation 2001

  • Govern the transport of radioactive substances by road

Next page: Radiation protection

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