Search

In order to calibrate radiation protection instruments and determine radiation dose, it is critical to establish an X-ray narrow-spectrum series recommended by the standard ISO 4037-1 which is published by the International Standardisation Organisation (ISO). By experiment, the qualities of filtered X radiation of narrow-spectrum series in the range from 60 to 300 kV were established. The differences of the first half-value layer (HVL1) and the second HVL (HVL2) between experimental results and the values given in the standard ISO 4037-1 were all within 5%. What is more, the Monte Carlo code EGSnrc was used to simulate the spectra of these radiation qualities, which showed a good agreement with these spectra given in the standard ISO 4037-1. The spectral resolution, mean energy and effective energy of these reference qualities can be obtained, which are all have good agreement with the given values.

In order to calibrate radiation protection instruments and determine radiation dose, it is critical to establish an X-ray narrow-spectrum series recommended by the standard ISO 4037-1 which is published by the International Standardisation Organisation (ISO). By experiment, the qualities of filtered X radiation of narrow-spectrum series in the range from 60 to 300 kV were established. The differences of the first half-value layer (HVL1) and the second HVL (HVL2) between experimental results and the values given in the standard ISO 4037-1 were all within 5%. What is more, the Monte Carlo code EGSnrc was used to simulate the spectra of these radiation qualities, which showed a good agreement with these spectra given in the standard ISO 4037-1. The spectral resolution, mean energy and effective energy of these reference qualities can be obtained, which are all have good agreement with the given values. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a Si(Li) detector was used to analyze mammographic X-ray spectra produced by an industrial equipment with Molybdenum (Mo) target, operating at constant tube potentials between 20 and 35kV. Filters of Mo and Al of suitable thickness were added to the tube exit, in order to reproduce the radiation qualities of an X-ray mammographic equipment, as recommended by the International Electrotechnical Commission (IEC 61267) and the Physikalisch-Technischen Bundesanstalt (PTB). A detailed evaluation of the detector response functions was made using Monte Carlo simulations. The validity of this method was tested through comparisons with the experimental spectra of radioactive sources. The results showed that the Si(Li) detector exhibits good response function in low energy (between 5 and 20keV). The measured X-ray spectra for a Mo filtration (0.03mm thickness), corrected using the response functions, show a good agreement with the reference clinical spectra. The results of this work also show that both the radiation qualities implemented and the spectra shape are consistent with that obtained for mammographic X-ray beams, and they can be applied to calibration of the mammography measurements instruments (e.g. ionization chambers and dosimeters). [Copyright &y& Elsevier]

Abstract: The aim of this paper was to evaluate the energy dependence of the kerma-area product meter Patient Dose Calibrator (PDC). The research was done using the calculation of the coefficient calibration of the air kerma values of different energies that are related to the radiation qualities provided on the International Standard of the International Electrotechnical Commission IEC 61267 for conventional X-rays, mammography and computerized tomography (CT), established at the Calibration Laboratory of IPEN. The calibration was made using reference ionization chambers with traceability to the Primary Laboratory Physikalisch-Technische Bundesanstalt (PTB), Germany. The energy dependence of the PDC was determined and the results showed that the PDC has small energy dependence, less than 6%, for the range of recommended energy while to the mammography range the values were 16% and for CT qualities the dependence was 1%. [Copyright &y& Elsevier]