In addition to the numerous measurement devices that Working Group 6.25 has for calibrating secondary standards by means of industrial X-ray tubes, this Working Group also has access to various medical X-ray facilities for conventional radiography and mammography for R&D. Working Group 6.25 also operates a 64-layer “GE CT 660 ASIR” CT scanner. This CT scanner is exclusively used for research purposes in the fields of dosimetry and image quality assessment (in cooperation with Working Group 6.24).