Study of a methodology for the calibration of kerma-area product meters in diagnostic radiology laboratories

Abstract

The aim of this project is to develop a methodology for determining the dose-area or kerma-area (DAP or KAP) product in the Metrology Laboratory of Ionizing Radiation of the Institute for Electrotechnics and Energy of the University of São Paulo (IEE / USP), and for the calibration of KAP commercial meters used in monitoring radiation doses delivered to patients undergoing radiological procedures. Accordingly, we intend to study the factors that influence the determination of kerma-area product and its uncertainties, in order to minimize them in the process of KAP calibration for both direct X-ray beams as attenuated by the detector. We also intend to investigate these parameters for different types of standard X-ray beams, used in dosemeter calibration. These beams shall be previously characterized in accordance with international standards (which adopt the PPV (Practical peak voltage) as a reference to the adopted voltage values), using dosimetric and spectrometric measurements. On the other hand, the reference ionization chambers that will be used in this process can be connected to two electrometers (PTW UNIDOS), alternately, but they were calibrated only in the set configuration (chamber + electrometer). So, is also a goal developing a methodology for calibration by components of the IEE reference dosimeters, including, in particular, a methodology for electric calibration in charge units of the available UNIDOS electrometers. The results of such activities will contribute to the student academic education in the field of Medical Physics, and broad the scope of calibration services to be offered in the future by the IEE / USP, reducing somewhat the burden on the Institute for Research in Nuclear Energy (IPEN / CNEN-SP), which is still the only institution to offer such service.