Abstract: A medical apparatus for (radiation) diagnosis or therapy can be provided with moving parts 6. Such an apparatus must be provided with a collision detection device 26, 28, 30. A known collision sensor measures the supply current for the drive motor and hence induces a high degree of inaccuracy in the collision detection. According to the invention the force applied to the moving part (image intensifier 6) is measured directly on the relevant part so as to be compared with an expected value, an alarm signal being generated when a threshold value for the difference is exceeded. The expected value is calculated while taking into account all movement and acceleration parameters of the apparatus. The expected values can be calculated in advance and stored in a look-up table or can be calculated, preferably while using a model of the apparatus, during operation of the apparatus.

Abstract: An apparatus for medical diagnosis and/or therapy is provided with an electromagnetic object sensor in order to prevent collisions between movable parts and, for example, a patient to be examined. The sensor may be provided with sensor electrodes 16 and 18 for capacitive detection of obstacles. In order to extend the area of sensitivity of the sensor electrodes in such a manner that it encloses the area in front of the X-ray entrance window 20 of the image intensifier 6, an additional electrode is provided in the beam path between the X-ray source 4 and the image intensifier, which additional electrode is coupled to sensor electrodes 18. The additional electrode includes a carrier which is provided with a thin metal layer, both being transparent to X-rays. The additional electrode may be subdivided into sectors 28-1, . . . , 28-4 which correspond to sectors 18-1, . . . , 18-4 of the sensor electrode in such a manner that the position of an obstacle relative to the image intensifier can be determined.

Abstract: An apparatus for medical diagnosis and/or therapy is provided with an electromagnetic object sensor in order to prevent collisions between movable parts and, for example, a patient to be examined. The sensor may be provided with sensor electrodes 16 and 18 for capacitive detection of obstacles. In order to extend the area of sensitivity of the sensor electrodes in such a manner that it encloses the area in front of the X-ray entrance window 20 of the image intensifier 6, an additional electrode is provided in the beam path between the X-ray source 4 and the image intensifier, which additional electrode is coupled to sensor electrodes 18. The additional electrode includes a carrier which is provided with a thin metal layer, both being transparent to X-rays. The additional electrode may be subdivided into sectors 28-1, . . . , 28-4 which correspond to sectors 18-1, . . . , 18-4 of the sensor electrode in such a manner that the position of an obstacle relative to the image intensifier can be determined.

Abstract: A medical apparatus for (radiation) diagnosis or therapy can be provided with moving parts 6. Such an apparatus must be provided with a collision detection device 26, 28, 30. A known collision sensor measures the supply current for the drive motor and hence induces a high degree of inaccuracy in the collision detection. According to the invention the force applied to the moving part (image intensifier 6) is measured directly on the relevant part so as to be compared with an expected value, an alarm signal being generated when a threshold value for the difference is exceeded. The expected value is calculated while taking into account all movement and acceleration parameters of the apparatus. The expected values can be calculated in advance and stored in a look-up table or can be calculated, preferably while using a model of the apparatus, during operation of the apparatus.