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Interlaboratory comparisons

  • One of the major tasks of the Federal Office for Radiation Protection's (BfS) Coordinating Office for Internal Monitoring is to support the approved laboratories for monitoring of internal exposures (ALMIEs) in their quality assurance.
  • Therefore the Coordinating Office takes care of the regular performance of proficiency tests in the in-vivo laboratories (direct measurements with whole-body and partial-body counters) and the in-vitro laboratories (analysis of biological samples).
  • These proficiency tests generally consist of two parts:

    • a practical part where the laboratories have to determine the activity in an anthropomorphic phantom or the activity concentration in a biological sample, and
    • a theoretical part, the so-called case study, where the internal dose has to be assessed by using monitoring data.

One of the major tasks of the Federal Office for Radiation Protection's (BfS) Coordinating Office for Internal Monitoring is to support the approved laboratories for monitoring of internal exposures (ALMIEs) in their quality assurance in all stages of assessing the internal dose. This means that the Coordinating Office performs regular proficiency tests in the in-vivo laboratories (direct measurements with whole-body and partial-body counters) and the in-vitro laboratories (analysis of biological samples).

A phantom made of bricks is used for the round robin tests Whole-body counter with phantom "Olga"The phantom "Olga" of the Federal Office for Radiation Protection (BfS) is measured in the whole-body counter of the University Hospital Essen as part of the 2018 round robin test using four sodium iodide detectors and a nitrogen-cooled germanium detector

These proficiency tests generally consist of two parts:

  • a practical part where the laboratories have to determine the activity in an anthropomorphic phantom or the activity concentration in a biological sample, and
  • a theoretical part, the so-called case study, where the internal dose has to be assessed by using monitoring data.

Also German non-governmental laboratories and laboratories from abroad may participate in the proficiency tests of the Coordinating Office for Internal Monitoring of the BfS. For the participation in the proficiency tests a fee will be charged according to the fee schedule or the service regulations of the BfS respectively.

In-vivo-Intercomparisons

The in-vivo proficiency tests are carried out once a year. They generally include

  • the measurement of the activity of a whole body phantom (replication of a human body) with a homogeneous distribution of given radionuclides and
  • the measurement of the activity of a thyroid gland-neck phantom (thyroid gland activity of iodine).
Rough scheme for the performance of an in-vivo proficiency tests (IC)
ActionDate
Announcement Beginning of the year
Preparation of phantoms
Carrying out the measuring campaign Late summer
Deadline for reevaluationsUp to two weeks after the measuring campaign
Information about the first evaluations by e-mail By beginning of the following year
Statistic evaluation of the resultsSpring of the following year
Possibility of statements by the participants

In-vitro-Intercomparisons

The in-vitro proficiency tests are carried out once a year. They generally include the determination of the activity concentration of given radionuclides in urine (and/or in faeces).

Performance of in-vitro proficiency tests
ActionDate
Announcement Middle of the year
Preparation of the samples
Forwarding of the samples to the participantsSecond half of the year
Participants inform about their results Beginning of the following year
Evaluation of the results
Informing the participants about first results (by e-mail)First quarter of the following year
Carrying out a workshop with the German-speaking participants Middle of the following year
Officially informing the participants about the results including the respective BfS report End of the following year

Realisation of case studies

Additional to the proficiency tests for quality assurance of laboratories for monitoring of internal exposures, dosimetrical case studies are carried out once a year as well. Also German non-governmental laboratories and laboratories from abroad may participate in the evaluation of case studies of the Coordinating Office for Internal Monitoring of the BfS.

In this theoretical part, on the basis of monitoring data the internal dose has to be assessed. These data can be fictitious or can be based on a real case of in-vivo and in-vitro monitoring and are described in detail in the specific case. Participation in the case studies is independent from the proficiency tests and does not require the capability to conduct measurements of internal exposures.

The time of the realisation of the case studies is matched with the intercomparisons. Announcement, distribution, and evaluation of the case studies are taking place in the third quarter of the running year. The final results including a model answer will be dispatched in the first quarter the following year.

State of 2024.01.26

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