IEC 61674:2012 specifies the performance and some related constructional requirements of diagnostic dosimeters intended for the measurement of air kerma, air kerma length product or air kerma rate, in photon radiation fields used in radiography, including mammography, radioscopy and computed tomography, for X-radiation with generating potentials not greater than 150 kV. This International Standard is applicable to the performance of dosimeters with vented ionization chambers and/or semiconductor detectors as used in X-ray diagnostic imaging. The object of this standard is to establish requirements for a satisfactory level of performance for diagnostic dosimeters, and to standardize the methods for the determination of compliance with this level of performance. This standard is not concerned with the safety aspects of dosimeters. The diagnostic dosimeters covered by this standard are not intended for use in the patient environment and, therefore, the requirements for electrical safety applying to them are contained in IEC 61010-1. This second edition cancels and replaces the first edition and constitutes a technical revision.