(1) This Procedure is intended to provide appropriate technical information to Radiation Safety Officers (RSOs) and outlines the requirements for personal radiation monitoring for UQ workers working with radiation sources. It is applicable to all University of Queensland (UQ) radiation workers as required by the Radiation Safety Regulation 2021. (2) Personal radiation monitoring is referred to under Section 38 of the Radiation Safety Act 1999 (the Act). As such, the following key controls are required: (3) Thermoluminescent dosimetry (TLD) and optically stimulated luminescence (OSL) dosimeters have been the most common means of monitoring the radiation exposure of users of gamma emitters - including unsealed sources of 125I and 51Cr and sealed sources such as 137Cs and 60Co. They are also suitable for persons working with diagnostic X-rays, including those used at UQ’s veterinary and dental practices. These personal dosimeters are available from service providers. (4) Electronic personal dosimeters (EPDs) may also be used to record X-ray and gamma ray doses. They can give continuous readout of cumulative dose and current dose rate and warn the person wearing it when a specified dose rate or a cumulative dose is exceeded. EPDs are especially useful in high dose areas, or for workers wanting to know the personal dose received from a new radioisotope in real time. (5) In the majority of cases, personal monitoring with conventional TLD or OSL is not required for users of X-ray fluorescence (XRF) and X-ray diffraction (XRD) units. Such equipment has either a totally enclosed target chamber or, where external beams are available, sophisticated interlock systems are fitted to prevent access to the direct beam. The very small diameter of the beam also means that any exposure that may have occurred would be only of a very restricted area and so would be unlikely to be detected by a conventional dosimeter worn on the chest or waist. (6) Users of neutron sources, which are incorporated in soil density or moisture gauges, are required to use specialised neutron dosimeters. Similar to TLD/OSL monitors, neutron dosimeters are available from service providers. (7) Beta radiation with average energies greater than 200 keV can be monitored using the standard TLD dosimeters supplied by service providers. The energy limitation means that only 32P and some of the less common high energy beta (or beta and gamma) emitters (e.g. 36Cl, 46Sc, 82Br and 103Ru) can be satisfactorily monitored with these personal dosimeters. (8) The OSL dosimeters are also sensitive to beta radiation, although the lower energy limit for useful results is 150 keV which effectively restricts their beta monitoring capability to 32P (and other high energy beta emitters listed above) and not for monitoring users of tritium, 14C. (9) Users of 32P must use TLD or OSL finger or extremity dosimeters, particularly where pipetting high specific activity stock solutions is a common practice. These are available from service providers. (10) Tritium and 14C have relatively low average beta energies and external monitoring is of little value when the relatively small amounts typically handled in laboratories are considered. In any case, the principal hazard of these substances is linked to inhalation or ingestion rather than external exposure. The control measures are therefore directed at entirely preventing the exposure rather than at monitoring and must be completed through the risk assessment process in UQSafe. (11) The instructions provided by the issuing service for each type of dosimeter must be followed closely, however, there are some procedures common to all personal monitoring practices, these are: (12) For UQ practices, the following monitoring periods are required: (13) These monitoring periods are for whole-body dosimeters only. Extremity dosimeters are generally changed monthly or according to the advice of the supplier. (14) It is the responsibility of the Organisational Unit to order and maintain their radiation dosimetry. Where radiation sources are used for the first time, or work is beginning with a new radioisotope or type of X-ray unit, the local RSO can contact the Radiation Protection Consultant (RPC) regarding personal monitoring requirements. (15) The cost of personal monitoring is the responsibility of the Organisational Unit where the radiation sources are used. (16) UQ has been granted three Possession Licences for the radiation sources under the Act. The Possession Licensee is responsible for ensuring compliance with both the legislation and specific licence conditions. (17) The Possession Licensee can nominate a nominee to carry out activities on their behalf and this can be any Senior Executive member. To be nominated, the Senior Executive member must contact the Health, Safety and Wellness Division (HSW Division) so the process can be completed and QRH be informed of the nomination. (18) The Nominee’s responsibilities, which can be delegated to Executive Deans, Institute Directors or Heads of School, are as follows: (19) The Act requires each Possession Licensee to appoint a qualified RSO. The RSO is required to: (20) The RPC provides overall guidance to all UQ workers on matters pertaining to radiation. The RPC monitors the implementation of UQ’s RSPPs as approved by the regulatory authority, provides support for radiation governance and compliance across UQ and monitors compliance with radiation safety legislation. (21) The RPC is the primary source of advice and expertise for: (22) In addition, the RPC provides reports regularly via the Director of the HSW Division, to Possession Licence nominees about any issues or changes that may affect the Possession Licence. (23) The primary responsibilities of a user are to: (24) Health, Safety and Wellness Division (HSW Division) is responsible for maintaining the required level of central oversight and assurance by: (25) This is a formal network of UQ RSOs. The forum allows the RPC and RSOs to consult on, and review regulatory, organisational and technical radiation matters at UQ. (26) The RSO Network meets four times a year and is chaired by the RPC. All participants are invited to contribute discussion and presentation items for the meeting. The RSO community provide secretariat duties as needed. All presentations and minutes are retained by HSW Division. (27) The RPC oversees radiation safety arrangement at UQ and reviews the specific aspects of radiation safety regularly. Local RSOs communicate radiation safety issues to the RPC as required. (28) Possession Licensees who are required to provide personal monitoring are obliged under Section 38(4) of the Act to keep up-to-date records of doses as assessed by the monitoring service. Personal monitoring records are to be kept for the duration of the wearer’s working life. The records are to be keep for not less than 30 years after the last exposure assessment, or at least until the person has reached the age of 75 years. (29) In practice, radiation monitoring records will continue to be kept by local RSOs for the possession licensee. (30) Personal dose records will be retained by local RSOs. The personal monitoring record for each monitored person must contain the following information: (31) The RPC is to also maintain, and annually review, central record keeping of the personal monitoring. This is achieved through the personal monitoring providers sending records to the RPC on an annual basis. (32) Section 38(2) of the Act requires the results of the assessment of dosimeters be provided to Queensland Radiation Health (QRH) as soon as practicable. To allow this to be done, possession licensees may approve the direct transfer of radiation monitoring results from the relevant monitoring service to QRH. (33) In the case of abnormal dose reading, the local RSO must inform the relevant worker, investigate why it happened, implement any new controls to minimise the exposure where applicable and meanwhile notify the RPC. If the personal dose is above the regulatory limit, it must be reported to QRH through the HSW Division.Personal Radiation Monitoring Procedure
Section 1 - Purpose and Scope
Section 2 - Process and Key Controls
Top of PageSection 3 - Key Requirements
Part A - Types of Radiation Monitors
Photon Radiation: X-rays and Gamma Rays
Passive Dosimeters
Electronic Personal Dosimeters (EPD)
Analytical X-rays
Neutron Radiation
Beta Radiation
Thermoluminescent Dosimetry (TLD)
Optically Stimulated Luminescence (OSL)
Finger/Extremity Dosimeters
Low Energy Beta Emitters
Part B - Using Dosimeters
Wearing Periods
Practice Category
Dosimeter Wearing Period
Unsealed sources research laboratories (beta or beta and gamma emitters)
3 months
Veterinary X-ray
3 months
Dental X-ray
3 months
Analytical X-ray
3 months
Soil moisture gauging
1 month
Fixed radiation gauges (service and installation only)
3 months
Managing Dosimeters
Section 4 - Roles, Responsibilities and Accountabilities
Possession Licensee
Nominee
Radiation Safety Officers (RSO)
Radiation Protection Consultant (RPC)
User
Health, Safety and Wellness Division
Radiation Safety Officers Network
Section 5 - Monitoring, Review and Assurance
Section 6 - Recording and Reporting
Record Keeping
Reporting of Radiation Doses
Section 7 - Appendix
Definitions
Term
Definition
Ionising Radiation
Electromagnetic or particulate radiation capable of producing ions but does not include electromagnetic radiation of a wavelength greater than 100 nanometres.
Optically Stimulated Luminescence (OSL)
A method for measuring doses from ionising radiation.
Radiation Safety and Protection Plan (RSPP)
Is the risk management plan for a particular type of radiation practice. The relevant RSPP must be complied with by all users and other persons involved in the practice.
Thermoluminescent Dosimeter (TLD)
A type of radiation dosimeter, consisting of a piece of a thermoluminescent crystalline material inside a radiolucent package. When a thermoluminescent crystal is exposed to ionising radiation, it absorbs and traps some of the energy of the radiation in its crystal lattice.
X-Ray Diffraction (XRD)
Is the elastic scattering of X-ray photons by atoms in a periodic lattice. The scattered monochromatic X-rays that are in phase give constructive interference.
X-Ray Fluorescence (XRF)
Is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by being bombarded with high-energy X-rays or gamma rays.
UQ Workers
For the purposes of this Procedure includes:
• staff - continuing, fixed-term, research (contingent funded) and casual staff
• contractors, subcontractors and consultants
• visiting academics and researchers
• academic title holders, visiting academics, Emeritus Professors, adjunct and honorary title-holders, Industry Fellows and conjoint appointments
• Higher Degree by Research students
• volunteers and students undertaking work experience.
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