Purpose
This procedure aims to ensure that employers have control over exposure to ionising radiation for all individuals working with ionising radiation sources. The procedure contributes to protecting employees and ensures compliance with current regulations.
Scope
The procedure applies to all units at the University of Oslo (UiO) where ionising radiation sources are used. To ensure that employees are sufficiently protected against harmful radiation doses, the employer must always assess the use of dosimeters.
Method
Determining who will use dosimeters
As a general rule, everyone working with radiation sources in monitored or controlled radiation protection areas must wear a personal dosimeter. A type of dosimeter suitable for recording radiation from the specific radiation source should be selected. The supplier can provide guidance on the choice of dosimeter type. Exceptions to the requirement for using dosimeters apply when radiation cannot be detected by dosimeters or if it is established that the use of the radiation source cannot result in doses exceeding those that the general population normally receives. If a dosimeter is not used, this assessment must be documented in writing and archived.
Individuals working in monitored or controlled areas but not directly handling radiation sources must wear a personal dosimeter if they are likely to receive a dose exceeding 1 mSv/year.
If the work situation leads to a significantly higher dose to the fingers than the rest of the body, finger or wrist dosimeters should be used. This is particularly relevant when handling large quantities of γ-emitting or β-emitting substances.
When working in controlled radiation protection areas, where doses can exceed 6 mSv/year, it is advisable to use electronic dosimeters, as these can provide immediate feedback on accumulated doses.
Requirements for providers of dosimetry services
Dosimeters are ordered from a supplier providing the dosimetry service most suitable for the specific radiation use. The supplier must make dose reports available to the individual ordering the service. The supplier must also report the measured doses to the Occupational Dose Register at the Norwegian Radiation and Nuclear Safety Authority (DSA).
Electronic dosimeters can also be acquired from suppliers who offer these.
The costs are covered by the relevant unit.
Monitoring dosimetry
If a person has received an elevated dose, the recipient of the report from the dosimetry service provider must inform the individual directly.
If a user receives a whole-body dose of more than 0.5 mSv over a 2-month period, the cause of the dose must be investigated. If necessary, work procedures, risk assessments, and safety job analyses should be revised. The results of the review must be documented.
Finger doses exceeding 25 mSv per measurement period must be followed up in a similar manner.
Information for users of personal dosimeters
Each person using a personal dosimeter must be informed that they have access to their own dosimeter readings in the Occupational Dose Register.
Archiving
All dose reports from the dosimetry service provider must be archived. The case folder should be titled: " Str?levernkontroll – doserapport – [navn p? enhet]". The journal entry should be titled: " Doserapport for perioden dd.mm.???? – dd.mm.????" and protected according to OF – offl § 13 jf fvl § 13.
Documentation of the review of a user's whole-body dose exceeding 0.5 mSv, or finger dose exceeding 25 mSv, over a 2-month period should be archived in personal files/student files. The journal entry should be given a title that makes it easily retrievable
References
Policy for radiation protection
Policy for systematic HSE work
Document information and change log
Responsible Unit: Section for Health, Safety, and Emergency Preparedness
| Version | Date | Brief description of change | Case No. | Signed by |
|---|---|---|---|---|
| 4.0 | 27.10.2025 | Procedure completely revised from previous version. | 2025/115115-4 | Johan L?berg Tofte |