Operational Rad protection Flashcards
How can exposures from sources be minimised?
House sources in protective rooms Tight control of room access Ensure room is clear before exposure Source state indicators Room accessibility indicators
What are the requirements for a prior risk assessment in IRR99?
Employer must make a suitable and sufficient assessment of any risks to employees to identify the measures needed to be taken to restrict the exposure to the employee
Must demonstrate the hazards ave been identified and the magnitude of the hazard has been evaluated
When do workers have risk of being exposed?
Remaining in bunker during treatment
Working close to klystron with HT on
Those regularly exposed to low levels induced in the linac head
Maintenance staff working close to linac head after high energy exposure
Unintended exposure from other sources
What are the measures to control access to a bunker?
Establish who is the operator in charge to have authority over access
What are the requirements of local rules for rooms?
Need to have unambiguous rules
Need to ensure employee contract states the rules must be followed
Responsibility and authority is clear
Clear and up-to-date information on safety state of room
Why are hand over documents required?
So controlled areas can be handed over to a different group or employer for servicing or research
Therefore groups have different local rules, standard operating procedures, and a different employer has responsibility
What do RT specific hand over documents include?
Formal removal from clinical use to prevent use prior to the arrival of service engineer
Explicit statement on service agency local rules
Statement of work required so local QC can be planned accordingly
What is the safety control hierarchy in RT?
Engineering controls
Procedural controls
PPE
What are examples of engineering controls?
Search buttons
Fail-safe door interlocks
What are examples of procedural controls?
Operator in control
Last person out activates switch
Exposure initiator responsible for checking room is clear
Room monitoring
What are examples of PPE?
TLDs
Source handling tools
Pb aprons for CT
Direct reading meters in brachy
What are the requirements for emergency stops and beam on signs in RT?
Need to be in a number of locations inside the room and the control room
Who should have their doses monitored?
Radiographers Physics staff Service staff Mould room staff Anyone regularly working in controlled areas
How are ‘other worksers’ protected?
Employers must take particular steps to prevent non-radiation workers receiving greater than 1mSv/year or any other dose limit
Should give information and training to those entering radiation environments
What are the requirements for QA in RT?
IRR99: employer shall make arrangements for QA for the purpose of ensuring the equipment remains capable of restricting dose in accordance with intended clinical purpose and research aims
As RT is high risk then constancy checks and periodic calibration of machines is needed
