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  • Influence of anode/filtrati...
    Kojić, Andrea; Kržanović, Nikola; Živanović, Miloš; Toroi, Paula; Bakrač, Luka; Božović, Predrag; Petrović, Jelena Stanković

    Radiation measurements, June 2024, 2024-06-00, Letnik: 174
    Journal Article

    Quality control and assurance of mammography X-ray generators include the use of solid-state detectors and/or ionization chambers calibrated in standard reference radiation fields. The IEC 61267:2005 standard defines reference mammography radiation fields for Mo/Mo anode/filtration, while various anode/filtration combinations are encountered in clinical mammography X-ray units. Not all Secondary Standard Dosimetry Laboratories have an X-ray generator with Mo/Mo radiation setup. Thus, traceability can be established only for the available anode/filter combinations, commonly limited to W/Al. In this study, W/Al radiation fields were established under laboratory conditions by performing half-value layer measurements. Then, four solid-state detectors were characterized. X-ray multimeter performance was evaluated in terms of energy response in the W/Al radiation fields. In the laboratory conditions, the energy response of the dosimeters had a large deviation from unity for dosimeters without appropriate anode/filter combination selected in the software settings, even though most of the dosimeters had a uniform relative response. The discrepancy in the response was further investigated by examining its variation induced by available detector software settings, and it was determined that the dosimeter response can vary up to 20 %. In a clinical setup, the half-value layer was determined, and detector performance was examined. Dosimeters were tested in clinical fields with Mo/Mo, Mo/Rh, W/Rh, W/Ag anode/filter combinations in the X-ray tube voltage range from 25 kV to 35 kV. For most clinical radiation fields, multi-element detectors had energy response deviation within ±5 %. The single-element detector had one software setting available and exhibited strong energy dependence. Extensive testing of detector response, such as presented in this paper. allows for correction factor interpolation based on the half-value layer. •IEC standard defines mammography reference radiation fields only for Mo/Mo.•Clinical mammography spectra differ due to various anode/filtration materials used.•Non-standard W/Al qualities for laboratory calibration purposes were developed.•Software induced changes in X-ray multimeter response for W/Al fields were examined.•Performance of X-ray multimeters in clinical mammography beams was evaluated.