Dosimetry • Ionizing radiation

Dosimetry and certification

Dosimetry is the quantitative determination of the dose absorbed by an organism or object following exposure to ionizing radiation.

A radiation protection tool, its purpose is to provide an estimate of quantities such as the effective dose (via the wearing of a whole-body dosimeter) or the equivalent dose (via the wearing of an extremity or crystalline dosimeter).

The SUCPR dosimetry service is accredited by the Agence Fédérale de Contrôle Nucléaire (Certificate of Accreditation EDD-0046176) to provide external dosimetry for professionally exposed personnel.

This approval was obtained on the basis of accreditation to ISO/IEC 17025(tests relating to the performance of external dosimetry - BELAC accreditation certificate: 495-Test).

To date, the SUCPR provides external dosimetry for exposed workers at ULiège, various hospitals, private companies and colleges in the region.

Whole-body dosimeter

In Belgium, anyone occupationally exposed to ionizing radiation must wear a dosimeter at chest level, except in certain specific cases (article 30.6 of the Royal Decree of July 20, 2001).

The technology chosen by the SUCPR for whole-body dosimeters is OSL (optically stimulated luminescence); it measures the dose received for photon (X, γ) and β radiation.

The operational quantities measured are the individual dose equivalents Hp(10) and Hp(0.07).
The communication threshold is 0.05 mSv for photons and 0.15 mSv for betas.

This type of dosimeter and the reading system are approved by the Federal Agency for Nuclear Control (AFCN).

The whole-body dosimeter is nominative. It records all doses received, whether worn or not, and is exchanged at the end of each month.

The detectors are read after the exchange. The results are analyzed and transcribed into a dosimetric report, which is then forwarded to the departmental results officers.

End dosimeter

Wearing an extremity dosimeter may be recommended for occupational activities involving a particularly high risk of exposure to ionizing radiation in the hands, such as interventional radiology or nuclear medicine.

The wearing of this type of additional dosimeter is decided by the physical control expert, possibly in consultation with the occupational physician.

It can be temporary (in the case of a workstation study, for example) or mandatory over the long term when a dose of 150 mSv over 12 consecutive sliding months is likely to be exceeded.

The extremity dosimeter supplied by SUCPR takes the form of a ring fitted with a lithium fluoride TLD pellet, and measures the dose received for X, photon or β radiation.
The operational quantity measured is the individual dose equivalent Hp(0.07).
The communication threshold is 0.1 mSv.

The dosimeter ring is nominative. It is worn for a period of one month, then exchanged at the same time as the whole-body dosimeter.

Crystalline dosimeter

The wearing of a crystalline dosimeter may be recommended for occupational activities involving a particularly high risk of exposure to ionizing radiation at eye level, such as interventional radiology or nuclear medicine.

The wearing of this type of additional dosimeter is decided by the physical control expert, possibly in consultation with the occupational physician.

It can be temporary (in the case of a workstation study, for example) or mandatory over the long term when a dose of 6 mSv over 12 consecutive sliding months is likely to be exceeded.

The crystalline dosimeter contains a lithium fluoride TLD pellet and measures the dose received from X-rays and photons.
The operational quantity measured is the individual dose equivalent Hp(3).
The communication threshold is 0.1 mSv.

It adapts to any protective support (goggles, visors, hoods, etc.). As with whole-body and extremity dosimeters, it is nominative and is exchanged monthly.