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Instructions - X-rays

X-rays are a type of ionising radiation and there are strict regulations governing use in the workplace.

Anyone wanting to acquire and use equipment and instruments capable of generating X-rays must follow these instructions. They apply to the all University campuses and to all Departments.

1. Justification

X-rays must only be used if there is no safer alternative way of carrying out the work and their use is unavoidable i.e. use of X-rays must be justified.

2. Risk Assessment
A radiation risk assessment must be carried out to identify the measures necessary to restrict the exposure of employees and others from X-rays. The work must not begin until the risk assessment has been undertaken.

The radiation risk assessment must identify X-ray exposure protection measures, such as safety features, maintenance requirements, designation of areas, radiation monitoring regimes, staff training needs, and plans for controlling exposure in the event of reasonably foreseeable accidents. It must be recorded in writing.

3. Critical Examination
A critical examination must be carried out by a Radiation Protection Adviser before the X-ray generating equipment is taken into routine use. The Radiation Protection Adviser may be the named adviser for the University or may be an agent of the equipment installer.
Critical Examinations must be carried out for new installations and if equipment has been moved, re-installed or following any maintenance and repair that could affect radiation safety aspects of the equipment.
The critical assessment must ensure that inherent safety features and warning devices for radiation safety operate correctly and that there is sufficient protection for persons from exposure to ionising radiation.
A record of the Critical Examination must be kept.

4. Area Designation.
X-rays must only be used in designated locations, either Supervised or Controlled Areas. The radiation risk assessment (Instruction 2) must identify whether a Supervised or Controlled area is required based on dose limits.
A Supervised Area must be designated if;
• the annual radiation dose to an employee (aged 18 or over) working in the area might exceed 1mSv,
• it is necessary to keep conditions in the area under review in case re-designation as a Controlled Area is required.
A Controlled Area must be designated if;
• the annual radiation dose to an employee (aged 18 or over) working in the area might exceed 6mSv i.e. 7.5µSv.h-1
• the risk assessment indicates that “special procedures“ must be followed to restrict exposure during normal operations or limit the probability of an accident,
• where access to anyone not connected with the work must be restricted.
Warning signs must be displayed at the entrance to designated areas.

5. Local Rules
Written instructions in the form of Local Rules must be produced for any Controlled Area or Supervised Area.
Local Rules must give instruction on carrying out work with X-ray equipment in ways that protect against the risk of radiation exposure, and give instructions on what to do in the event of an accident (a contingency plan). They must also include the name of the Radiation Protection Supervisor for the Area, a description of the Controlled or Supervised area, reference to relevant radiation risk assessments, instruction on what monitoring must be carried out, and contingency measures to be taken in the event of a known or suspected exposure..
Local Rules must be on display in the Area in which the X-ray equipment is located.

6. Radiation Protection Supervisor.
There must be a Radiation Protection Supervisor appointed for the Area in which the X-ray equipment is located.

7. X-ray equipment inventory
The University Radiation Protection Officer must be provided with information about equipment and instruments capable of generating X-rays (‘Registration’ of X-ray sources).
This must be done so that an up-to-date inventory of X-ray sources can be kept by the Health and Safety Department for auditing purposes.
The University Radiation Protection Officer must be notified if X-ray generating equipment is moved to a different location and when it becomes redundant.

8. Classified Worker

Anyone carrying out work with X-rays where there is a risk of annual whole body dose of more than 6mSv per annum or a finger dose more than 150mSv, must be registered as a Classified Person.

The need to register Classified Persons will be identified by the Radiation Risk Assessment (Instruction 2).

Classified Persons must have a medical carried out by a Health and Safety Executive appointed doctor. Medicals must be arranged through the Health, Safety and Occupational Health Services.

9. Personal Dosimetry
Personal radiation exposure monitoring (dosimetry) must be provided if the radiation risk assessment (Instruction 2) indicates that it is necessary. There are two types of dosimetry badge; film badges for measuring whole body radiation, changed at 2 monthly intervals and thermoluminescent devices (TLD) finger badges for measuring doses to the hand, changed monthly.
If risk assessment indicates that personal dosimetry is necessary the local Radiation Protection Supervisor must be contacted, who will advise on the local administrative arrangements for obtaining and returning dosimetry badges.
Anyone issued with badges must use them as instructed and must return the badges for dose analysis at stipulated times.

10. Radiation workers

Only authorised staff and students are allowed to work with X-ray generating equipment.
Staff and students must receive training before starting work with X-ray generating equipment. They must understand the hazards from ionising radiation and must be knowledgeable about and competent to use control measures to minimise risk. They must also be trained to understand the importance of security arrangements.
Staff and students must be authorised by the RPS for the area, based on them having received training.
The radiation risk assessment must identify what level of training and competence is needed for staff working with X-ray generating equipment.

11. Monitoring
Monitoring using a suitable instrument must be carried out at regular intervals to confirm that exposure control measures are effective. Records must be kept of the results, and if corrective action is necessary, details of any work carried out and subsequent confirmatory test results must be recorded.

12. Monitoring Instruments.
Monitoring instruments used to check exposure control measures e.g. Geiger counters, NaI detectors used to detect X-ray stray field leakage, must be tested regularly and calibrated annually.
The University Radiation Protection Officer must be provided with information about monitoring instruments. This must be done so that an up-to-date inventory kept by the Health and Safety Department for auditing purposes.

13. Contingency arrangements
Contingency arrangements must be produced, identifying the actions to be taken should someone believe that they have received an accidental exposure. The arrangements must be written as part of the Local Rules (Instruction 5)