GENERATION OF DIAGNOSTIC X-RAY RADIATION QUALITIES IN THE SSDL X-RAY SYSTEM ACCORDING TO IEC 61267 STANDARD

Ionizing radiation metrology laboratories generate their own gamma and x-ray radiation qualities with respect to reference radiations generated by international standards, such as IAEA (International Atomic Energy Agency) used for the radiotherapy field, ISO (International Organization for Standardization) used for the radiation protection field and IEC (International Electrotechnical Commission) used for the diagnostic field. IEC constructed standards of four reference radiation qualities (RQR, RQA, RQC and RQT) representing radiation energy qualities used in the diagnostic radiology. In this regard, SSDL (Secondary Standard Dosimetry Laboratories), in parallel with developments in the diagnostic radiology, have desire to carry out the calibration and test responsibility of dosimetry and measurement devices to be used in the diagnostic radiology by generating their own radiation energy qualities and reference dosimetry standards. The first step of this study is to obtain x-ray radiation qualities. Diagnostic RQR radiation qualities represent radiation beams applied to patients in general radiography, fluoroscopy and dental practices. RQR radiation qualities were obtained according to criteria specified in IEC standard. According to IEC standard, half value layer (HVL) filtered and unfiltered air kerma dose rates are predicted to be a value between 0.485 and 0.515. In our study, those values were found to be between 0.497 and 0.506. Reliability and conformity of obtained qualities were determined by using various measurement techniques. In the second step of the study, after obtaining reference standard dosimetry calibrated in PSDL, which will constitute the national standard, the international standardization will be extended throughout the country by providing calibration services for dosimetry and measurement devices to the users in the diagnostic radiology.