key points from radiology new guidance Flashcards
which two organisations are involved in this guidance?
PHE
FGDP
title of guidance
PHE and FGDP 2020 Guidance Notes - Safe Use of Dental X-ray Equipment
who does the guidance apply to?
primarily GDPs
why was the guidance produced?
replaces prev guidance notes from 2001 in response to IRR17 and IRMER17
IRR17
legal duties when using ionising radiation in the workspace
IRMER17
legal duties if exposing pts to ionising radiation
RPA
an individual who is competent to advise on radiation protection
usually a medical physicist (not a dentist)
QA
checks to ensure that your work meets the required standards e.g. ensuring that radiographs are diagnostic and that the dose remains ALARP
controlled area
an area in which a person must take special precautions to restrict significant exposure to ionising radiation
notable changes in the new guidance
image quality rating QA testing of digital display screens contingency plans QA testing of digital receptors dental x-ray room warning signs dose monitoring
why is QA testing of digital receptors necessary?
they are reused (unlike film) and so become damaged over time
how often should QA testing of digital receptors be carried out?
every 3m or whenever damage is suspected
aspects of QA testing of digital receptors
visual inspection
image uniformity
image quality
QA testing of digital receptors - visual inspection fail criteria
damage to wires, casing or phosphor
QA testing of digital receptors - image uniformity
expose receptor to an unattenuated x-ray beam and check resulting image (which should show a consistent shade of grey across entire image area)
QA testing of digital receptors - image uniformity fail criteria
evidence of significant deterioration compared to baseline image
any artefact that may affect clinical image quality
QA testing of digital receptors - image quality
take radiograph of a test object and assess resulting image against a baseline e.g. step wedge
QA testing of digital receptors - image quality fail criteria
evidence of significant deterioration compared to baseline image
image quality rating - A
diagnostically acceptable no/min errors in either pt prep, exposure, positioning, image (receptor) processing or image reconstruction and of sufficient image quality to answer the clinical Q targets - digital ≥95% - film ≥90%
image quality rating - N
diagnostically not acceptable
targets
- digital ≤5%
- film ≤10%
QA testing of digital display screens - why must monitors be routinely checked?
they need the correct properties to accurately display radiographs (such as adequate contrast, resolution, brightness etc)
will deteriorate over time
QA testing of digital display screens
use a suitable test pattern - can access online - SMPTE
should be undertaken every 1-3m
dental x-ray rom warning signs
must be visible at every entrance to a CA
- e.g. doorway of surgery when x-ray equipment is in a
state of readiness to emit x-rays
can be notices/lights and should include the IR trefoil symbol and suitable wording
warning notices need to be removed/covered when the CA is not present (e.g. when power supply to x-ray equipment is turned off)
- coincident warning lights may be more convenient as they can be wired to turn off automatically with the x-ray equipment
contingency plans
immediate actions undertaken in the instance of a “reasonably foreseeable radiation accident”
e.g. pressing the Emergency Stop button if the pan machine fails to rotate but is still exposing the pt to radiation
what must happen if a contingency plan is enacted?
the incident must be investigated (with the RPA) to reduce risk of recurrence
records must be kept for at least 2yrs
HSE must be notified of any significant radiation exposures
how often should staff rehearse contingency plans?
annually
2 types of dose monitoring
monitoring of staff who enter CAs
monitoring of CAs and potential CAs
monitoring of staff who enter controlled areas
RPA can advise when this is necessary
- potentially needed if there are significant changes to
radiographic workload, x-ray equipment, radiographic
techniques or layout of surgery
- can be considered for pregnant employees
personal dose should not exceed 1 millisievert p.a. (otherwise investigation along with the RPA is indicated)
monitoring of CAs and potential CAs
to check if CAs need to remain designated as such, and if adjacent areas need to be designated as CAs
should be checked evert 3yrs
RPA can advise on best method of monitoring
what does IRR17 come under?
H and S at Work Act 1974
what is IRR17?
legislative framework for protection of persons who are exposed to IR at work, and other persons e.g. public who may be incidentally exposed
components of IRR17
1 - registration with HSE
2 - notify HSE about radon where levels higher
3 - consult a RPA
4 - restriction of exposure to employees and public
- optimisation ALARP, dose limits
5 - design of facilities
6 - safety and warning systems
7 - procedural controls
8 - critical examination
9 - radiation risk assessment (with RPA)
10 - controlled areas
11 - dose investigation level <1mSv p.a.
12 - local rules
13 - contingency plans
14 - Radiation protection supervisor
15 - maintenance and examination of engineering
controls
16 - information, instruction and trainingdose limits
effective dose 6mSv pa
extent of a controlled area
whole room
within 1.5m of the xray tube and pt, and within primary beam until it has been sufficiently attenuated by distance or shielding
who does IRMER17 apply to?
pts having xrays for diagnostic or tx planning purposes
exposure of carers and comforters
individuals who have xrays taken using dental x-ray equipment for non-medical reasons
pts or other persons who volunteer to take part in research programmes involving xrays
GDC CPD radiography recommendation
at least 5hrs of verifiable CPD every 5yr cycle
administrative aspects of IRMER17
identify staff roles - entitlement of duty holders Employer's procedures Medical physics expert QA of written procedures QA of equipment QA of images
referrer
HCP entitled to refer individual for xrays
ensure sufficient clinical info provided
if referrer is not same person as practitioner what must be provided?
must provide info in writing, include:
- pt identification
- clinical info (inc any prev medical imaging)
- referrer identification
- date of referral
practitioner
HCP entitled to take responsibility for an individual medical exposure
role is justification
justification by practitioner
does benefit to pt from diagnostic info obtained outweigh detriment from exposure?
- availability and findings of prev radiographs
- specific objectives of exposure in relation to history and
exam of pt
- age (increased radiosensitivity in children)
- total potential diagnostic benefit to individual
- radiation risk
- efficacy, benefits and risk of available alternative
techniques having the same objective but involving
no/less exposure to IR
make a written record of the justification decision ‘authorisation’
if reject request - record reasons and inform referrer
authorisation should be carried out in advance of exposure except e.g. surgery where dentist shouldn’t leave to document authorisation. Do ASAP after
operator
any person who is trained and entitled, in accordance with EPs, to carry out all or part of the practical aspects associated w a radiographic exam
employer
legal responsibility
provide framework, involving written procedures, protocols, QA programmes and training, to ensure safe clinical practice
what roles is it common for GDP to be?
referrer, practitioner and operator
Employer’s Procedures
identify staff roles, training
identify individual
pregnancy enquiry
info on benefits and risks of procedure
dose constraints and guidance for carers and comforters
clinical evaluation of outcome of each exposure - pt notes
assessment of pt dose
setting, use and review of DRLs
reducing probability and magnitude of accidental/unintended exposures
significant and clinically significant accidental or unintended exposures
- analysis, recording and reporting - need system in place
QA of EPs
employer’s duties under IRMER
produce and ensure EPs are adhered to referral guidelines (inc for dental CBCT if applicable) guideline exposure protocols
Medical Physics Expert
need to appoint one - person who has knowledge, training and experience to act/give advice on matters relating to physics applied to exposures of the type subject to the regulations
- optimisation
- measurement methods
- using DRLs
- advice
- liases with RPA where appropriate
what must be done for carers and comforters?
carry out risk assessment
every exposure must be justified by practitioner separately to pts exposure
exposures taken for non-medical imaging purposes
EPs should detail
exposures for research purposes
has to have been approved by a research ethics committee (REC)
IRMER17 - 2 major aspects
optimisation of pt dose
administrative aspects
IRMER17 - optimisation of pt dose
selection of xray equipment
selection of image processing and viewing facilities
operation of dental xray equipment
use of pt contact shielding (not recommended for routine use)
IRMER17 - optimisation of pt dose - selection of x-ray equipment
x-ray source assembly
beam filtration (1.5mm Al for ≤70kV)
display and recording of parameters relevant to pt dose
IO
- operating potential 60-70kV
- rectangular collimation
- FSD at least 200mm
- sufficient range of exposure time and/or tube current
settings available to enable even the fastest digital
imaging systems to be exposed correctly and
consistently
IRMER17 - optimisation of pt dose - selection of image processing and viewing facilities
display screen equipment and viewing conditions
consult MPE
film-based imaging systems and viewing conditions - light box
IRMER17 - optimisation of pt dose - operation of dental xray equipment
IO
- rectangular collimation (40x50mm for size 2 IR)
- BAD and IR holders
- operating potential (higher setting = lower pt dose =
worse image quality)
- FSD
- select appropriate exposure settings
- compatibility with digital IRs
IRs
- digital dose reduction compared to film
- if film - use F speed
IRMER17 - optimisation of pt dose - use of pt contact shielding
not recommended for routine use
aprons not required ever as main beam should never be directed towards abdomen
thyroid shields - better to use appropriate equipment, exposure factors, technique, collimation, field limitation
- use if thyroid gland may unavoidably be in primary beam (get advice from MPE)
purpose of QA in radiology
ensure consistently adequate diagnostic info, while radiation doses to pts (and other persons) are kept ALARP, taking into account requirements of IRMER17 and IRR17
formal records
areas of QA
EPs
xray equipment and pt dose
image processing and display equipment
image quality
basic principles of QA
implementation of QA should be responsibility of a named person (usually practice owner or senior partner)
only undertaken by suitably trained staff
freq defined
content of essential supporting records, also freq for formal auditing of the records and required retention times
QA programme of EPs
Radiation protection file
- radiation risk assessment, local rules, contingency
plans and EPs
- keep it all together in a known location
- maintenance of a procedures log
QA procedures for training
- register of all staff involved, their responsibilities and training, date for review of training needs
QA programme for x-ray equipment
equipment inventory
adequate testing
routine testing and tests after repairs or modifications
in-house QA checks on x-ray equipment
QA of clinical image quality
image quality ratings
image quality analysis
reject image recording and analysis ‘N’
QA of clinical image quality - image quality analysis
at least every 6m
≥100 images
record as well as any actions taken in response
QA of clinical image quality - reject image recording and analysis ‘N’
record date, nature, known/suspected cause, number of repeats (if taken)
QA audits
person with overall responsibility for QA programme should check full programme at least every 3years clinical audits/peer reviews - QA programme and associated records - justification and authorisation - CE
dental x-ray equipment engineers
provide info e.g. room plans
installation of equipment
disposal or selling on of x-ray equipment
cut electrical power cable once disconnected from mains, remove/obscure and trefoil symbols - alarm to people
tubehead contains lead - get a contractor
RPS
person appointed in accordance with IRR17 who is responsible for day to day supervision of work with ionising radiation
- e.g. ensures local rules are followed
RPA
person consulted in accordance with IRR17, to give advice on radiation protection and compliance with IRR17
QA programme for image processing and viewing facilities
QA tests for digital image receptors
display screens and viewing conditions
film based imaging systems
QA programme for image processing and viewing facilities - film based imaging systems
film speed, exp date and recommended storage conditions
processing conditions (times and temps)
changing freq for processing solutions
cleaning instructions for automatic processors
QA of film processing
- test object e.g. step wedge, after every change of processing solutions
QA checks on light-boxes and viewing conditions - at least every 6m
QA programme for image processing and viewing facilities - what must you do if manual film processing?
check darkroom/processing unit remains light tight and safelights don’t produce fogging of films
film for 10mins below safelight with coin on
- shouldn’t see image of coin on processed film
- can do with safelight off to check general light tightness
of room
- at least every 12m
