Calibration of semiconductor detectors for dosimetry in diagnostic radiology

Abstract

The ionization chamber is the standard instrument for dosimetry in diagnostic radiology. Alternative detectors are those based on semiconductor technology. These dosimeters don't require corrections for pressure, are rigid and smaller than ionization chambers, and provide real time information. The main disadvantage of these devices has been their energy dependence which differs considerably from that of ionization chambers. In Technical Report Series n°457 the International Atomic Energy Agency (IAEA) proposed the 'substitution method' for calibration of dosimeters at secondary standard dosimetry laboratories (SSDL) based on a comparison between the measured air kerma with a reference ion chamber and a user dosimeter to be calibrated. The present study describes the results concerning the implementation of this method for semiconductor detectors calibration in a laboratory other than a SSDL. The overall uncertainty was better than 7.5% (coverage factor k = 2), being the uncertainty of the reference chamber better than 5%. © 2009 Springer-Verlag.