Radiation Legislation and Safety Flashcards
What is the name of the main piece of radiation legislation?
The Ionisation Radiation Regulations 2017 (IRR17)
- covers all uses of radiation and radioactive materials
When did IRR17 come into force?
January 2018
What is the biggest change in the new IRR17 from the 99 version?
How you inform the Health and Safety Executive of your work with ionisation radiations
- You must now apply to notify, register and receive consent.
What is meant by notify, register and consent?
Notify
- lowest risk
- not cost to practise and no expiry date
- notification is needed for each practise
Register
- medium risk
- register as a radiation practise with HSE
- initial cost of £25 and renewal required every 5 years
Consent
- highest risk
- licensing or approval
- requires additional information
- £25 with annual renewal
- needed for each practise
What is the change been made about the exposure to the lens of the eye?
Employees 18+ exposure has been reduced 150mSv to 20 mSv
What other changes have been made in the new IRR17?
- The term ‘radiation employer’ has been replaced with ‘ an employer who carries out a practise that involves ionisation radiation’
- Need to complete an estimate of how much radiation dose will affect the public.
- Dose records now only need to be retained for 30 years instead of 50
What is the date that notify, register and consent applications had to be submitted by?
6 Feb 2018
What must be done before working ith ionising radiation?
Identification of all hazards that have potential to cause radiation accident.
Evaluation of the magnitude of these risks to the employee
Risk assessment and implementation of measures to restrict radiation exposure
Employers must train employees - provide info and equipment etc to reduce radiation exposure risk
What is another piece of legislation that applies more to veterinary radiography?
BVA’s
Guidance notes for the safe use of ionising radiations in veterinary practise
What are the 3 principles of radiation protection?
TIME (hold down the button)
DISTANCE (from the tube head)
SHIELDING
What three things should you consider when radiographing as well as time, distance and shielding?
- Clinical justification
- Minimum Exposure (stand back, protection etc)
- No dose limit should be exceeded (don’t exceed maximum permissible dose)
What is an RPS?
Radiation Protection Supervisor
Who can be an RPS?
Practise Principle
Head Nurse
What is the RPS responsible for?
Responsible for ensuring that radiography is carried out safely and in accordance with regulations and the local rules (Day to Day)
- they dont need to be present for every xray
What is an RPA?
Radiation Protection Adviser
What do you require to be an RPA?
Either a diploma in veterinary radiology or have another qualification like medical physics and an interest in veterinary radiography
and from January 2005, they must hold a certificate of competence from an appropriate issuing body.
What are the 3 main responsibilities of an RPA?
Advising the practise on radiation protection
Demarcation of the controlled area
Draw up local rules and written systems of work
What must the written systems of work include?
- Must gove a copy to everyone that is working with Xrays
- Should indicate estimated personal dose estimated
- Xray should be unplugged after each session
When would an RPA not be required?
If all 5 are met:
- Only 1 vertical beam Xray machine
- A LBD to ensure that the primary beam does not come within 10cm of the edge of the table
- Table covered in 1mm of lead over an are >10cm in each direction from the largest area of the primary beam
- The equipment operates at <100kV power
- Workload does not exceed 4mA minutes
What should the controlled area room materials be like?
Thick walls
Reinforced with lead if required
Lead screens
Consider the flooring also
What rules should the controlled room meet?
- Allow for standing at least 2m from primary beam
- Defined by RPA
- Its demarcated with warning areas (the whole area if possible)
- Warning signs and symbols at entrance
- Red light to warn radiography in process and prevent accidental injury
- Xray machine should have light or sound to indicate when machine is on
When can a controlled area be used as a normal room?
When the Xray machine is unplugged from the power source, it ceases to become a controlled area
What can we do to measure tube head leakage?
Can put a dosemeter on top of the beam for a few radiographs and then send away
What must the thickness of beam filtration be?
At least 2.5mm of aluminium equivalent
What must all Xray machines be fitted with?
A collumation device (ideally an LBD)
What are the requirements of an Xray table?
Must be lead lined
or have >1mm thick lead sheet larger than the max beam size on or beneath the cassette
(absorbs residual primary beam and reduces scatter)
How often do Xray machines need to be serviced?
At least once per year
What must be recorded when taking a radiograph?
- Date
- Patient identity and description
- Exposure factors
- View
- Quality of image
- Means of restraint (if the animal is being held, then the names of those holding must be recorded)
What is protective clothing?
Aprons, gloves etc made of rubber impregnated with lead
Does protective clothing protect against the primary beam?
No just scatter
What extra precautions are in place for equine radiography and why?
Use thyroid protectors also as the beam may e horizontal
What is the lead equivalent of a protective apron?
Minimum 0.25mm LE - most are 0.35mm,
Double sided offers best protection
What is the lead equivalent of lead gloves?
0.35mm. (0.5mm for equine)
What are the rules for a dosemeter badge?
- Wear at trunk waist level beneath the apron
- Worn only by person its issued to
- Must not be washed, tumble dried or left in the xray room
- Dont wear outside premises
- Must be changed at recommended times
What are the 2 types of dose meters?
Film badges and Thermoluminescent dosemeters (TLDs)
Describe film badges
Small piece of blue film within a plastic container.
Contains small metal fibres that allow the assessment of the type of radiation to which the badge has been exposed
Describe how a TLD works
- They contain radiosensitive lithium fluoride crystals and are usually orange
- On exposure to radiation , the electrons in the crystals are rearranged, thus storing energy
- During the reading process, the crystals are heated and give off light in proportion to the amount of energy which they have stored - this gives a quantitative reading.
Where should dose meters be sent to?
The National Radiological Protection Board
How often should film badges be sent to NRPB?
Every 1-3 months depending on work load
What are does limits? The amount of radiation that…?
Aunt of radiation which are thought not to constitute a greater risk to health than encountered in everyday life
What are the limits for the skin, extremities and lens of the eye for people in the practise?
For employees or trainees 18+:
Skin = 500mSv (1cm square)
Extremities = 500mSv
Lens of Eye = 20mSv
For trainees <18yrs:
Skin = 150mSv
Extremities = 150mSv
Lens of the Eye = 15mSv
For everyone else and employees under 18:
Skin = 50mSv
Extremities = 50mSv
Lens = 15mSv
Who should not be present at radiography?
An owner
Anyone under 16yrs
Pregnant women
Ideally who should be present at radiography?
Only the person making the exposure
minimum number of people!
What do the local rules inform about?
Equipment, procedure and restriction of access to controlled area.
Restraint methods and precautions
Assessment of the maximum dose received
Who should have the local rules?
Everyone involved in radiography (including nurses) and it should be displayed in the Xray room
What direction should the beam be pointed?
Vertical
What size should the beam be?
It should be collimated to the smallest size possible and must be within the borders of the film.
When should grids be used?
Grids only to be used if area is >10cm thick
What must be done if a grid is used?
Multiply the exposure factor by the grid factor
What is the quote from the IRR17 about restraint ?
Only in exceptional circumstances should be a patient or animal undergoing a diagnostic examination be supported or manipulated by hand
What are ‘exceptional circumstances’?
Severely ill or injured animal:
- congestive heart failure
- ruptured diaphragm
- any severe trauma
If sedation or GA would be detrimental to the animals health - there needs to be sound clinical justification
What 4 things make Xrays so dangerous?
Invisible
Painless
Cumulative
Damage to living tissues
What are the somatic effects of radiation?
Skin redening and cracking Blood disorders Baldness Cataracts Digestive Upset, dehydration
What are the carcinogenic and genetic effects of radiation?
Tumors can develop in exposed tissues
Genetic mutations can occur in germ cells in gonads leading to inherited abnormalities
What are the 2 sources of radiation?
Tube head
Primary Beam
What can be done to reduce exposure?
Use a LBD to collimate
Decrease kV where possible
What causes scatter?
When the primary beam hits a solid object
What can scatter cause in terms of the image?
Fogging and Blackening
What does increasing the kV do?
It increases the energy of the X rays and it can reduce definition and increase scatter
What can be done to reduce scatter?
Tight collimation of the primary beam Compression of large areas of tissue Reduce kV where possible Lead-backed cassette Lead top table
What are the radiological rules that must be followed?
Only X ray if clinically indicated
Avoid unnecessary repetition of X rays
Direct the beam towards the ground if possible
Position the animal on top of a lead table
Immobilise animals (sedate/GA)
If required, share restraint duties to minimise exposure
Never do human radiology
If staff pregnant, cease radiography and report to RPS
What is another piece of legislation used for veterinary radiography in addition to the IRR17?
BVA:
Guidance notes for the Protection of Persons Against Ionising Radiations Arising from Veterinary Use
What is the radiation limits for the abdomen of a women of reproductive capacity and pregnant women?
13mSv for 3 month periods at a time
10mSv for entire pregnancy
What is the national average radiation dose?
2.2mSv
How should waste chemicals be disposed?
Collected and disposed of by a licensed waste disposal company
What are the legal requirements in terms of hazardous waste?
Environmental Agency must be notified when hazardous waste is produced or removed from any premises.
Records for types and quantities of waste must be kept for at least 3 years
Veterinary surgeries exempt - so none!