Radiation Safety Flashcards
How do we know about errors that have happened?
CQC annual IRMER report shows us what kind of incidents have happened (imaging vs therapeutic) and where in the pathway they have occurred, delivery phase most common
Who refers and what must they provide
Usually comes through MDT but individual referrer must be identified, usually oncologist. Must provide practitioner with sufficient medical data to allow practitioner to justify exposure. Practitioner could be same person
No requirement for record of this
Who can refer?
Must be healthcare professional but could be different groups
Decided on a local level
Physicist may be able to refer for repeat planning scan for example. Common for oncologist to refer for all exposures in pathway
What are referral guidelines?
Recommendations for exposures including radiation doses. Must be available to referrer.
Tells referrer when RT is appropriate: eg histology report indicates particular stage of disease. Includes imaging dose.
Referral guidelines must be established under IRMER
Who is responsible for justification of an exposure, what else are they responsible for and what should they consider?
Practitioner
Also responsible for ‘other such aspects of an exposure’ such as optimisation.
Ideally justify concomitant exposures at the same time
Justification means showing sufficient net benefit
Should consider other options which don’t require ionising radiation (although this doesn’t need doing each time, if NICE guidelines say RT is SOC, this is sufficient), should consider the potential therapeutic benefit to the patient as well as detriment
Who can be a practitioner and when might a new practitioner be necessary?
A registered healthcare professional who the employer’s procedures say can take on responsibility for exposures
Decided at a local level
If additional exposures are required such as new planning scan following weight loss then need a new practitioner
Who is the operator?
Anyone who can carry out practical aspects of treatment, including supporting functions
Eg oncologist, physicist, treatment radiographer, technologist, treatment planner
What is authorisation and who authorises?
An exposure can only be carried out if it has been authorised by the practitioner or operator. If not practicable for practitioner, operator can do it.
Person carrying out exposure must know that it has been authorised, easy to have a policy so they know how to find this out
Could be paper signature or electronic signature in R&V system
Why is authorisation separate from justification?
May be range of possible exposures which meet criteria of justification.
Separate authorisation allows operators to make decisions about exposures without practitioner present. Allows steps between decision to treat and readiness to deliver treatment to be checked.
What are RT considerations of optimisation?
Exposures of target volumes must be individually planned and delivery verified taking into account doses to non target volumes must be ALARP.
Does not mean every patient needs dose distribution calculated
For TPS planned patients, dose constraints, full delineated CT etc
For palliative patients, less effort put into optimisation, for unplanned patients small margins
Imaging must also be optimised
Why are we more concerned about children exposures
Children have longer for latent effects to show
Children have organs that are closer together and may be more sensitive
What groups require further optimisation and what optimisation could be done?
Children and pregnant women
May not treat until end of pregnancy, more likely to use fewer fractions or a lower dose bath, should keep dose to foetus below 10cGy, rule out pregnancy if unknown
Child specific dose protocols, OAR constraints, CT scan protocols
What is a clinical evaluation
Requirement that every exposure has a recorded clinical evaluation as an outcome
Doesn’t need to be report. Should show that exposure was used for intended purpose, informing borders of disease, producing plan, checking position.
What are protocols for standard radiological practice
Required by IRMER, clinical protocols that guide selection of dose regimes, constraints, verification techniques, VMAT etc
What makes an MPE?
Being on the RPA2000 list.
Usually embedded in department, but no requirement to be hired by trust, and could advise remotely
What must MPE be involved in?
Optimisation
QA of processes and equipment
Dosimetry
Patient protection
Protection of others
Dose measurement
Radiation equipment specification
Involved in analysing incidents, advising on remedial action, interpreting IRMER
When must an incident be reported?
When it is a significant accidental or unintended exposure
OR is clinically significant
What guidance exists for when to report and who do we report to?
CQC SAUE guidance
CQC in England
If clinically significant, should tell patient, referrer, practitioner
Guidance from professional bodies saying what is clinically significant: IRMER: implications for clinical practice in RT Guidance from the RT board
What is clinically significant?
IRMER says up to professional bodies to decide
Came up with incident that has had a measureable effect on the patient’s tumour control, toxicity or QOL.
Practitioner should decide what is CS
What are DRLs?
Dose reference levels
Different to diagnostic reference levels. Expect more variation because scans have different expectations: need high quality for SRS and higher dose for instance
Should still investigate if exceeding DRLs consistently
What are MDGN
Medical and dental guidance notes
Good practice guide for use of ionising radiation in clinical setting
Chapters specifically for brachy and RT
What was purpose of TSR and what did it provide?
Reduce errors
Provided classification system (out of date now) and allowed national sharing of incidents and national trends to be seen
PHE TSR reports encourages notification of non reportable incidents so lessons can be learned
What should you do in event of potential SAUE?
Immediately make preliminary investigation
If cant rule out SAUE, notify CQC within 2 weeks
Full investigation, notify full outcome by time CQC say (12 weeks)
What do CQC say is reportable wrt planning scans?
If the planning scan needs to be repeated twice to get an appropriate dataset
What do CQC say is reportable wrt verification images?
If set up error or hardware/software failure leads to 3 or more imaging exposures at a single fraction
When the number of additional imaging exposures is 50% greater over the course of the treatment due to protocol failure (eg imaging panel is not out so scan must be repeated) or hardware/software failure
What do CQC say is reportable wrt therapy exposures?
Delivered dose to TV or OAR is 1.1 times higher over the whole course or one fraction is 1.2 times higher than planned dose
Delivered dose to TV is less than 0.9 times the intended dose over the whole course
What do CQC say is reportable wrt geographic miss?
All total geographic misses are reportable, even for single fraction or significant part thereof
Partial geographic miss where miss exceeds 2.5 times locally defined error margin and guidelines dose factors for PTV or OARs are exceeded (decided by department and varies, 5mm miss in SABR significant, 2cm miss in palliative patient where fatty tissue is exposed may not be)
Who is usually practitioner?
Usually CCO is practitioner, and they give a single justification for an entire set of RT exposures
