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Calibration of dosimeters used in mammography with different X-ray qualities (tube voltages from 20kV to 50 kV)

Project Description

A set of X-ray qualities containing different anode (Mo,W,Rh) and filter (Mo,Rh,Pd) materials for mammographic X-ray equipement is defined in table 1 of IEC 1223-3-2 : 1996 (acceptance tests - imaging performance of mammographic X-ray equipement). Fpr the calibration of dosimeters used in mammography, presently only qualities produced by Mo-anode, are defined in IEC-1267:1994.For thhe time being only a few laboratories are equiped with X-ray tubes with Mo-anode capable of providing these X-ray quality for calibration purposes. On the other hand a number of "similar" radiation qualities from X-ray tubes with W-anode are available both at standard and calibration laboratories being worth to be considered as an alternative to the X-ray qualities defined in the IEC 1267. These include qualities defined by BIPM-CCEMRI and ISO 4037-1:1996 (narrow and high kerma rate spectra) as well as those X-ray qualities from IEC 1223-3-2 which can be produced by existsing X-ray tubes with W-anode.

The goal of this Euromet project is to investigate the suitability of these alternative X-ray qualities for the calibration of dosimeters used in mammography. The criteria in the validation of these alternatives should match to the requirements of IEC 61674:1997 (dosimeters with ionisation chambers and/ or semi-conductor detectors as used in X-ray diagnostic imaging) as far as intrinsic error and energy response of dosimeters are concerned.

  • Inquiry among partners to identify the individual contribution of participating laboaratories, X-ray qualities and dosimeters (ionisation chamber and semi-conductor type) to be investigated in this project.
  • Comparison of calibration (-factors) of dosimeters used in mammography obtained fro different X-ray qualitis identified above
     

The collaboration of further laboratories is welcome. Please inform the proposer in due time, not later than March 99.


Final Report 2003-12-31

The project was successfully competed.
The effect of different X-ray radiation qualities on the calibration of mammographic dosemeters was investigated within the framework of a EUROMET (European Collaboration in Measurement Standards) project. The calibration coefficients for two ionisation chambers and two semiconductor detectors were established in 13 dosimetry calibration laboratories for radiation qualities used in mammography. They were compared with coefficients for other radiation qualities including those defined in ISO 4037-1 with first half value layers in the mammographic range. The results indicate, that the choice of the radiation quality is not crucial for instruments with a small energy dependence of the response. However, the radiation quality has to be chosen carefully, if instruments with a marked dependence of their response to the radiation energy are calibrated.
The detail final report was agreed and sent to all participants. Short version of the final report “Calibration of dosemeters used in mammography with different X-ray qualities” was submitted and will be published in the Radiation Protection Dosimetry Journal.

Subjects
Ionising Radiation (IR)
Coordinator
Joseph Witzani, BEV (Austria)
Coordinating Institute
BEV (Austria)
Further Partners
IAEA
SIS

Information

Reg. No.
526
Collaboration Type
Research
Status
completed
Starting
2000-12-01
Completion
2003-09-01