Physics 3 Legislation Rida Flashcards
Where do our regulations come from?
What are the 3 core concepts of regulations?
Limitation
Justification
Optimisation
What limit must doses not exceed?
ICRP recommended limits
What is ALARP
Doses must be As Low As Reasonably Practicable (ALARP) taking into account economic and social factors
Who is the IRR 17 for
Staff and public
Who is IRMER 17 for
Patients
What 3 things are in the basic radiation protection?
- Limit time working in the area when radiation is in use
- Keep your distance from the source of radiation:The inverse square law
- use shielding defences
What is the inverse square law
2 times as far away = reduce dose by 4 times 10 times as far away = reduce dose by 100 times
What 3 shielding defences can there be?
Permanent, portable, personal
Who is the IRR 17 enforced by
Health and safety executive (HSE)
What is the graded approach?
Notify HSE of work with ionising radiation, or seek Registration or Consent
What comes under notification?
Work in an atmosphere with a concentration of radon above a specified level
What comes under registration
• •
Registration
Operation of x-ray generating equipment Working with radiopharmaceuticals
What comes under consent
• Manufacturing of radiopharmaceuticals
• Administration of radiopharmaceuticals
• Operation of linear accelerator
• Use of High Activity Sealed Sources (HASS)
What underpins all other safety methods?
Radiation risk assessments
Why must a radiation risk assessment must be done?
- Before new equipment is put into use
- If there are any changes to the type of work / amount of work
- On a regular basis
What must we identify in a risk assessment
- Who is at risk
- What the risks are (e.g. external irradiation, ingestion of radioactivity…)
- Dose estimates for those at risk from normal operation
- Reasonably foreseeable radiation accidents (identify them & dose calc)
- Contingency plans for these radiation accidents
- WRITE IT DOWN
What are the hierarchy of controls?
For every “reasonably forseeable radiation accident” there should be a ..
contingency plan in place to reduce likelihood of occurrence and reduce harm in the event that it does occur
Should contingency plans be rehearsed?
Yes, The frequency and nature of rehearsal depends on the risk.
What 5 things constitute the local rules?
• Systems of work to keep your radiation doses low
• RPS name
• Description of designated areas
• Investigation dose levels
• Contingency plans
Who must read the local rules
Everyone who enters the controlled area must read them
What is a RPS and what do they do?
Radiation protection supervisor (RPS)
The Employer must appoint (at least one) RPS
Their role is to ensure compliance with the Local Rules
RPS should be:
• Suitable trained (they must understand the hazards and how to reduce risk)
• In day-to-day contact with the work (they need to supervise!)
• Sufficiently senior to be able to command authority
• Given sufficient resources (e.g. time) by the Employer to carry out their role
What’s an RPA and what do they advise?
Radiation protection adviser
- risk assessment
- local rules
- contingency plans
- incident analysis
- personal dosimetry
- designation of areas
- plans for new installations
How do we monitor personal dose?
• Directly measuring your radiation dose
• Estimating doses in a risk assessment
• Or a combination of the two!
- Sample monitoring for 3 months
- Compare to dose limits
- Include results in risk assessment
What are the dose limits of the body, eye, skin and extremities of employees under and over 18 and others?
What is the IRR17 dose limit that must not be exceeded for whole body
20 mSv
What whole body effective dose is at classification level? (Not necessary for dentists)
6 mSv
What whole body effective dose is at investigation level?
More than 1mSv per year
What whole body effective dose is at typical dose level?
Less than 1mSv per year
If a sign says radiation controlled area ☢️ what does this mean
• Follow special procedures to restrict radiation exposure
• Effective dose greater than 3/10th dose limit
• Effective dose could be greater than:
• 6mSv (whole body)
• Equivalent dose could be greater than:
• 15mSv (lens of eye)
• 150mSv (extremities / skin)
What’s the easiest and most practical way to demarcate controlled areas?
Use the walls
What are the 2 demarcations of controlled areas
1- dedicated dental X-ray room
Sole purpose of the room is for x-ray (e.g I/O, OPT, CBCT)
Designate entire room (including console area behind lead screen).
Whilst unit connected to mains
2- intraoral tube in dental clinic
Inappropriate to classify entire room
Designate 1.5m area around the tube
Need to be careful with control of access (responsibility of the operator of the x-ray equipment)
Who is the IRMER 17 enforced by?
CQC
Who are the 3 IRMER duty holders under the employer
Referrer - request the radiation exposure
Practitioner - justifies the exposure
Operator - performs the exposure
What does the employer do/ not do
The Employer takes on overall responsibility for IRMER compliance. They can delegate tasks but they cannot delegate responsibility.
what does the referrer do?
• Provide patient demographic information
• Provide a clinical history
• Specify exactly what imaging required
• Identify themselves
• Must not refer outside scope of practice
What does the practitioner do?
• Is the clinical indication in line with referral criteria?
• Does the benefit outweigh the risk?
• Is there another modality that would be more appropriate?
• Has the patient recently had imaging that already provides the clinical information required?
• In most cases, the practitioner will be a dentist
Who is an operator?
Anyone who has any impact on the successful outcome of a medical exposure
• Dentist
• Dental nurse
• Dental hygienist
• physics staff
What does an operator do?
What does an Operator do?
• Identify the patient
• Set exposure factors
• Test the x-ray equipment
• Optimise image quality & dose
The Employer is legally obliged to appoint one (or more) ____ in order to advise on compliance with IRMER17.
MPE
Medical physics expert
What are the 5 stages of quality assurance testing?
Acceptance
Commissioning
Routine quality assurance
Decommissioning
Procurement
What is a diagnostic reference level?
Typical dose for standard patient having a standard exam on standard equipment
What is the national DRL
Enable benchmarking of practice against national standards.
What is the local DRL
Enable comparison of performance of different equipment. Helps to target optimisation strategies
What is the general technique for calculating local DRL
• Dose audit – get all patient doses in each x-ray room for a set period of time
• Calculate the mean/median patient dose for each exam
• Calculate the mean of room mean/medians
• This is your local DRL
Why do many dental centres adopt the National DRLs as their local DRLs?
In dental radiography there is little variation in patient dose.
How can we optimise imaging?
1) Select exposure parameters that reduce the dose to below the NDRL.
2) Optimise post-processing in order to improve displayed image quality.
What if there accidental or unintended exposure?
CQC need to know , in leeds dent institute this is done on Datix
Accidental vs unintended
Accidental = an individual received an exposure when no exposure of any kind was intended
Unintended = although an exposure was intended, the exposure they received was significantly greater or different to that intended.
In extreme cases of non compliance with the IRMER what may the CQC issue?
Prohibition notice summary
