Radiation Protection Legislation
- lonising radiations are potentially damaging to the
human body and can produce deterministic and
- X-rays and Radioactive isotopes used for
imaging and treatment
- Radiotherapy doses are higher but diagnostic
contributes more to population as a whole
- Of the 15% of medical dose of entire population almost 90% is from radiography
– CT = 7% of procedures
– CT = 47% of annual collective dose from diagnostic imaging
- Do not occur below a threshold dose
- Severity increases above threshold dose
• Skin erythema at 3 Gy – small area
• Nausea/vomiting at 1 Gy – whole body
• Cataract at 5 Gy – eyes
- No threshold dose
- Risk of damage increases as dose increases
- At low doses biological effects are not predictable
- BUT there is always some risk
• Inherited disease
Inherited radiation damage
- Does not introduce new, unique mutations
- May increase the incidence of the same mutations
that occur spontaneously
The aims of radiation protection are:
- To prevent deterministic effects by keeping
doses below the thresholds for those effects
- To reduce the risk of stochastic effects to
levels which are considered acceptable
Ionising Radiations Regulations 1999
– These cover the use of ionising radiations in the workplace
– Responsibility of both employer and employees
Ionising Radiations (Medical Exposures) Regulations 2000
– To protect the patient
– Employers/employees must ensure that x-ray equipment, shielding & SOPs meet adequate standards of radiation protection
– Care Quality Commission oversees compliance
Principles of Radiation Protection
- Justification – Clinical value of the image obtained must outweigh the risk incurred by the radiation dose required
- Optimisation – ALARP
- Limitation – staff and general public (not patients)
A few IRR 1999 Regs
- Dose Limitation (11) – 20 mSv/yr workers & 1 mSv/yr public
- Management of Radiation Protection (13) – RPA/RPS
- Information, Instruction and Training (14) – all employees
- Controlled Area (16) – >3/10 dose limit (must be restricted)
- Local Rules (17) – read and signed by all employees
- Designation of Classified Persons (20) – personal dosimetry
A few IR(ME)R 2000 Regs
- Application (3)
- Interpretation (2) – Who is Employer, Referrer,
Practitioner, Operator, Practical aspect, DRLs
- Duties of Employer (4)
- Duties of Practitioner, Operator and Referrer (5)
- Justification of Individual Medical Exposure (6)
- Optimisation (7)
- Clinical Audit (8)
- Expert Advice (9)
- Equipment (10)
- Training (11)
- Employers responsible for setting local DRLs
- DRLs should be reviewed annually
- Provides a formal mechanism for revision of locally adopted DRL values which may follow revised or new national DRLs
- Where examination protocols have been changed, the effect on the locally adopted DRLs should be considered
- The existence of a National DRL should not be considered as a reason for establishing a Local DRL. E.g. if you do very few skulls
Patient dose surveys
Radiography/ / Fluoroscopy
- Each x-ray unit for all standard radio-diagnostic exams
- Frequency determined by the RPS / manager, in consultation with the RPA (not less than three yearly)
- At least ten patients, but preferably twenty
- Weigh 60 kg (9 st 6 lb) – 80 kg (12 st 8 lb)
- Average compared to the DRL
- If greater than the DRL – RPS investigates and initiates
Risk to Patients
“The probability of a fatal cancer being induced
in an individual patient from a single X-ray
examination is very small and is dependent on
the age of the patient as well as the type of
- Risk of severe hereditary disease (considering all subsequent generations) is estimated at 2% per Gray where the gonads of young people are irradiated
- Risk of childhood cancer following in utero irradiation of a foetus is 6% per Gray
- Positive net gain
- Radiographers must understand dose levels and risk
- Radiographer can assist the clinician in arriving at an
informed ‘risk benefit’ assessment
Triage nurse requested x-rays
- Protocols vary, but usually A/E depts allow requests for limb radiology in patients over 5 years old
- Have they received enough training?
- What action would be required if a request form for facial bones was signed by an A&E nurse?
Should a radiographer accept the role of practitioner in A/E?
- Awareness of the magnitude of the responsibility
- Recognition of his/her own limitations and confidence in his/her knowledge and professional training
- Responsibility of practitioner lies in justifying the procedure based on clinical information supplied
- Should cooperate regarding practical aspects with other specialists and staff involved in medical exposure
- Must also comply with employers policies / procedures
ALARP principle/Optimisation of dose
- Biological effects of ionising radiation
- Choice of equipment
- Good technique
- Good positioning and immobilisation of patient and equipment
- Good communications
- Well-trained staff
- Quality assurance programme
- Record doses – DAP meters (assess patient dose, adherence to
- Clinical audit – tested against standards
- Policies made (with regard to children, preg., adhering to local
- Reporting incidents or problems with equipment
Patient doses not recorded?
- RPS competent?
- Advice taken from medical physics expert
- IR(MER) 2000 – policies written on roles of
- Staff motivation?
- Negligence – disciplinary action?
Application of IRR (1999) and IR(ME)R (2000)
- Consider what is meant by
- Consider the risk of ionising radiation to staff (radiology and other health care professionals), patients and the general public and how this can be minimised.
- Distinguish between “deterministic effects” and “stochastic effects” and which are we most concerned with in medical imaging and the overall aim of radiation protection.
- The three main principles of radiation protection are
- How/when are these applied?
- What are the relative radiation doses between various procedures?
- Remember there are two sets of regulations in the UK which govern the use of ionising radiation, one relates more to the patient and one relates more to the staff members?
- Do dose limits apply to patients?
- What is a controlled area?
- Consider “Local Rules”, “RPS” and “RPA”.
- The duty holders under the regulations are employer, referrer, practitioner and operator, what are they responsible for?
- What are radiation protection protocols and how/when do they apply?
- Consider ways to achieve “ALARP”
- Don’t forget the importance of QA.
- How does “Education and Training” fit in with radiation protection?
- Remember to apply theory to practice where relevant.
- Name 4 radio sensitive parts of the body
- How can you check the identity of a child?
- How do you confirm the identity of an unconscious patient?
- Why is it important to control secondary radiation?
- What is the minimum lead equivalent of lead rubber
aprons used above 100kV?
- If you find a crack in a lead rubber apron, what would you do?
- What radiation protection measures should you take in resus?
- If you are using a mobile unit how long should the exposure cable be?
What would you do if you were trying to take X-rays in resus and one of the nurses was pregnant?
- What is the controlled area around a mobile unit?
- How do you ensure the safety of a mobile unit left unattended in resus?