PMDs (often in the form of a badge) detect and record an accumulated radiation dose over a set period. PMDs are usually worn at work by a worker for three months. The PMD is then sent to the dosimetry service provider for analysis and the measured accumulated dose is reported to the employer.
The accumulated dose reflects the amount of radiation that the worker has been exposed to and can alert an employer to any inappropriate exposure during the wear-period and can help determine if adjustments to work practices are required to protect employees from excess exposure.
Occupations requiring use of a PMD
Employers must provide a PMD to each worker occupationally exposed to radiation in the following areas
- industrial radiography
- nuclear medicine
- equine veterinary radiography
- scientific research in laboratories classified as medium or high-level laboratories where radioactive substances not contained in a sealed source device are used
- diagnostic or interventional radiology (other than dentistry, veterinary and chiropractic applications)
- neutron based detection, analysis and gauging when used in borehole logging
- servicing of ionising radiation apparatus or devices containing radioactive substances.
Responsibilities of employers and employees
- Employees are legally obliged to wear the PMD provided while using ionising radiation during employment.
- Employers must ensure the background radiation received by the worker is also measured during a wear-period so the excess dose received from occupational exposure can be calculated. Background radiation is measured by a control PMD stored on site in an area that will not be exposed to radiation.
- After a wear-period has lapsed, all PMDs must be returned to the service provider for analysis, including any unissued, unworn and control PMDs.
- If a lead apron is worn during a procedure that involves the use of radiation, the PMD should be worn under the apron.
- Where radiation is being used in a medical procedure in theatre, only those directly involved in the procedure are required to wear a PMD. Those who are incidentally in theatre and not directly involved in the radiation procedure are not required to wear a PMD.
- Employers who are concerned about occupational exposure but are not required under the Regulation to provide a PMD, should perform a risk-assessment to aid their decision making.
Recording personal radiation exposure
Employers must keep a record of the doses received for each employee with a PMD, and these records should be regularly reviewed (e.g. quarterly).
The dose record for each person provided with a PMD must contain
- The amount of radiation to which the person has been exposed as measured by the dosimeter. The dose should be recorded in sieverts.
- The results of any tests carried out by the employer to determine the amount of radiation to which the employee has been exposed.
Records must be kept for each worker issued with a PMD containing
- full name, sex and date of birth
- current home address or if no longer employed, the last known home address
- the date employment commenced and ceased
- the kind of work performed details of the types of ionising radiation to which the worker may have been exposed to in the course of their employment, including information about unsealed radioactive substances to which they may have been exposed
- details of any radiation accidents involving or affecting the worker
- PMD details, including the type of monitor, where on the body it was worn and the name of the PMD service provider
- the radiation exposure dose results for the employee.
When a worker leaves their place of employment, the employer must provide
- A copy of the worker’s radiation exposure records to the worker. This must include all annual dose records and any subsequent periodic reports received after the worker has ceased employment
- An additional copy of the radiation exposure records to the new employer if requested by the employee. These records are required to be given to a new employer so that an assessment can be made of possible future doses that can be received to keep an employee under their annual limit.
- An employer must ensure the following warning is included on copies of radiation exposure records provided to an employee.
These records should be kept safely and permanently and be given to any future employer employing you as a radiation worker.
- Employers must make a worker’s records available for them to see at a convenient time during normal working hours.
Managing employee dose rates
Employers should review dose reports as they are received from dosimetry service providers in conjunction with previous reports. to determine if the worker's previous 12-month and five-year dose rates are within the required annual limits (an average of 20 mSv over five consecutive calendar years and no more than 50 mSv in any one year).
Employers should note any high doses received by workers. The PMD service provider should highlight these high dose rates when reporting PMD analyses. If the reported dose rate exceeds an average of 400 microsieverts (µSv) per week over the wear period, the worker may have received a high dose and employer should investigate the cause.
If a high dose report is received, the EPA may require a written explanation from the employer about the circumstances of the high dose. A change in work practice or role should be considered to manage an worker's annual dose.
PMD service providers
Employers must only use PMD providers that have been approved by the EPA.
Division 2 of the Radiation Control Regulation requires that employers ensure that all monitoring devices that are issued or installed are checked, maintained and calibrated in accordance with the EPA Guideline: Monitoring Devices (PDF 121KB).
For further information, contact the EPA's Hazardous Materials, Chemicals and Radiation Section on (02) 9995 5959 or 131 555.