RS Regulations Flashcards
What are the three principles of radiation protections from the ICRP? (6 marks)
- Justification = the benefits should outweigh the risks.
- Optimisation = doses should be optimised such as the doses are as low as possible taking into account the equipment, image quality required and intended purpose.
- Limitation = doses to everyone should be kept alarp.
What is IRR99 about? (6 marks)
- Protection of staff and members of public from hazards associated with working with ionising radiation
- Includes local rules, dose limits, requirements for QA, designation of areas, and individuals required RPS etc.
From IRR99, what are the dose limits for classified workers and non-classified workers? (7 marks)
Classified: WB = 20 mSv ED Extermities = 500 mSv Eq dose Skin = 500 mSv over 1 cm^2 Eyes = 150 mSv
Non-classified it is 1/3 of these limits roughly…
Limit to abdomen over a woman of reproductive capacity is 13 mSv over a 9 month period.
For an employee declared pregnant it is 2 mSv over the remainder of the pregnancy.
What is meant by the term classification? (5 marks)
Required when an employee is expected to receive 3/10ths of any dose limit or 6 mSv ED.
They will need to have an annual medical by approved doctor. Possibly carry a passbook, if work with other employers in controlled areas.
Need to use an ADS for dose monitoring.
What is the IDR and TADR, TADR 2000 and what limits are there? (12 marks)
Instantaneous dose rate = measure in uSv per hour during exposures averaged over 1 minute. Limits for controlled, sup and public are: 2000, 7.5, 7.5.
TADR = Time averaged dose rate over 8 hr day taking into account workload of the area. Limits = 7.5, 2.5, 0.5.
TADR 2000 = time averaged dose rate over the working year, takes into account workload and occupancy. Limits = 3, 0.5, 0.15.
How should entrances to designated areas be demarcated? (3 marks)
- Indication of the nature of the hazard with a trefoil.
- Indication that only authorised personel should enter
- Eye height and could have staged lights
What is the role of the RPA and the RPS? (6 marks)
RPS is responsible for day-to-day safety in the controlled area. Ensure that the local rules are up to date and fit for purpose. They should be senior enough to be able to enforce the local rules and work in that area on a daily basis if possible.
RPA has the main role on advising the RPS on how they can implement the local rules and abide by the legislative requirements. They might perform QA and help with commissioning of new equipment, RP requirements also.
What are the dose constraints for comforters? (1 marks)
5 mSv over 5 years. Rather than 1 mSv per calendar year.
What is IRMER 2000 about? (2 marks)
Protection of patients from harm of medical exposures which use ionising radiation. Keeping doses ALARP. Optimisation of exposures, DRLs etc.
What is the role of the practicioner, operator and referrer? (9 marks)
Referrer: have the authority to request that a patient has a procedure carried out which requires exposure to ionising radiation. Should be written into the local procedures. They should provide enough information to the practioner so that they can justify the request, such as a unique patient identifier (NHS no), patient details and reason for the request, as well as pregnancy status! This could be a GP.
Practicioner: responsible for justifying the procedure based on the information from the referrer. This could be a superintendent radiographer.
Operator: individual responsible for performing any practical aspect of an exposure, e.g. a radiographer.
What are DRLs? (3 marks)
- Units usually based on things like total DAP or ESD
- They are reference levels for commonly performed diagnostic procedure, which if breached, may indicate that some optimisation is required and should be investigated
- Can be national DRLs which are based on national data using a standard patient (~70 kg +/- 5 for the mean of the data set)
- Can also be set at a local level if this is more appropriate
From IRMER2000, give the MGTI multiplying factors (8 marks)
Low dose procedures such as extremity or skull x-ray = 20
Medium dose procedures such as abdo x-ray or mammo = 10 times
High dose diagnostic such as fluoro or abdo CT = 1.5
RT treatment = 1.1 for whole treatment or 1.2 per fraction delivered.
What are the limits on leakage and filtration on an x-ray set? (3 marks)
Leakage = 1 uSv per hour over 100 cm^2 at 1 m from the focal spot
Filtration = 2.5 mm Al equivalent or which 1.5 mm must be permanent for DR , 0.5 mm for mammo
When is classification required and what requirements will the employer need to fullfil? (4 marks)
When 6 mSv ED WB or 3/10ths of any equivalent dose limit is likely to be breached in any calendar year.
Will need to have annual medicals, use an ADS and possibly a passbook.
What types of dose monitors are used for personal dose monitoring? (3 marks)
- TLDs such as LiFl.
- Optically stimulated devices which use AlO crystals.
- Electronic devices which give instant measurements, but they are expensive.
