Abstract: While acquiring a tomographic image, the position of patient's head is continuously measured and recorded. For this purpose, several cameras (5) are arranged at the tomograph (1). They measure the position of a reference device (4), which is mounted to the teeth of the patient's upper jaw. Infrared-diodes are arranged on the reference device (4), the position of which is recorded by the cameras (5). This allows to measure the movements of the patient and to compensate for them when generating the tomographic image.

Abstract: For cooling a grate block which forms a part of a grate for plants for the thermal treatment of waste material, a closed cooling chamber inside a block body of the grate block below an upper wall bearing the waste material is filled with cooling water and is closed in a sealing manner from the bottom by a base provided with an insulation layer. Effective cooling of the parts of the grate block which are subject to the greatest thermal loading takes place, greatly reducing the temperatures. Since thermal expansions in the material are dispensed with, a grate-block row can be formed by only a few grate blocks screwed to one another. The assembly and exchange of grate blocks are simpler; and the undesirable dropping of waste material through the grate between the grate blocks is largely eliminated. Additionally, the grate blocks can be produced from less expensive material.

Abstract: To cool a grate block which forms a part of a grate for plants for the thermal treatment of waste material, a closed cooling space in the grate block below an upper wall supporting the waste material is filled with cooling water. Water feed lines and water drainage lines pass through the cooling space, end in the cooling space, and respectively have a plurality of outlet and inlet openings, so that, in addition to an effective cooling which greatly reduces the temperatures, an optimum distribution of cold water and hot water also takes place in the cooling space. Since thermal expansions in the material are dispensed with, only a few screwed-together grate blocks can form a grate-block row. The assembly and exchange of grate blocks are simpler and an undesired amount dropping through the grate between the grate blocks is eliminated to a great extent. Moreover, the grate blocks can be produced from a less high-alloy material.