reliable sensor - net module: Enabling application - specific nodes

Radiographic apparatus includes indicium means for indelibly imprinting computerized axial tomographs with identification data which relates to the position of the tomographic slice in relation to a fixed datum position such as the top of a patient's head. The indicium comprises a member having characteristically varying radiopacity which is positioned in the vicinity of the radiographic slice so as to be scanned by the exploring radiation and is fixedly secured in relation to the datum position.