Siemens Aktiengesellschaft

Werner Kuehnel

Manfred Rattner

Walter Beyerlein

Gerhard Kratz

Jens Fehre

Joerg Dorn

Heinz Baumann

Otto Ebersberger

X-ray apparatus has a d.c.-a.c. converter circuit supplied with energy that is connected via a line connection to a high-voltage transformer supplying the high-frequency operating voltage to an X-ray tube. The line connection has a first and a second conductors that are insulated from one another and are disposed close to one another for achieving a low line inductance. These conductors have ratio of radius to conductor thickness such that a low ohmic impedance is established.

X-ray apparatus and line connection therefor

An arbitrary voltage distribution can be achieved in a high-voltage generator which supplied an X-ray tube having a metallic central part, wherein the anode voltage and the cathode voltage are generated in the high-voltage generator by two series-connected high-voltage rectifiers with respective preceding high-voltage transformers, whereby the high-voltage transformers being supplied by an inverse rectifier. A clocked switch, via which the average value of the anode current can be set and matched to the cathode current, lies in the lead to the high-voltage transformer at the anode side.

High-frequency voltage generator for supplying an X-ray tube

In a high-voltage generator with an X-ray tube having a metallic middle part, unfavorable effects due to a part of the current flowing off via the grounded metallic middle part is avoided by the overall voltage across the X-ray tube being produced by one inverter and the cathode voltage of the X-ray tube is generated by another inverter, each having a high-voltage rectifier connected thereto. The respective voltages are regulated by controlling the respective inverters.

High-frequency voltage generator for an X-ray tube

An x-ray diagnostics installation has a detector for the mean image brightness in a predetermined region which is within the x-ray beam path. The detector is formed by a matrix of individually activateable detector elements. A control unit, connected to the detector, has a memory in which data sets are stored respectively corresponding to different anatomical parts and positions of those parts. A selection unit identifies and selects a data set corresponding to the anatomical part currently being examined, and the detector elements in the array corresponding to that part are then activated via the control unit. The radiation incident on the acitvated detector elements is then compared, in the aggregate, to a rated value, and the radiation dose is controlled on the basis on the comparison.

X-ray diagnostics installation having a mean image brightness detector

A circuit for controlling a medium frequency x-ray diagnostics generator, the generator having a power rectifier connected to a main power source having an unknown internal resistance. A low-voltage filter stage, and inverter, a high-voltage transformer, and a high-voltage rectifier are connected in sequence between the power rectifier and an x-ray tube. A control unit for the x-ray tube is provided which controls the x-ray tube input current dependent upon the input voltage to the inverter, so that the x-ray tube voltage is maintained constant independently of the internal network resistance of the main. The generator can thus be connected to different mains having different internal resistances without affecting operation of the x-ray tube, making the generator suitable for use as a portable generator. A capacitance connected in the generator preceding the inverter, such as in the low-voltage filter stage, insures that the inverter input voltage will change more slowly than a rate at which the x-ray tube current can be changed.

Medium frequency x-ray diagnostics generator power control

In an exemplary arrangement a rotatable scanning system comprises an X-ray tube which emits a beam of X-rays which penetrates the layer to be examined, and a radiation receiver which supplies electrical output signals corresponding to the measured radiation intensity. A computer is connected to the radiation receiver for calculating the attenuation values of specific image points of the irradiated body layer from the output signals of the radiation receiver. An inductive transformer is provided for transmitting energy to the X-ray tube, its secondary winding being arranged in a fixed position relative to the X-ray tube and rotating with the scanning system and its primary winding being fixed relative to the stationary part of the unit.

Tomographic X-ray diagnostic unit with the secondary of the high voltage

In an exemplary embodiment a direct-current supply with adjustable d.c. voltage supplies an inverter which in turn drives the high-tension transformer. High-tension capacitors are connected at the output of the high-tension rectifier, and control loops are provided for the x-ray tube voltage and the x-ray tube current. The controlled variable is the inverter frequency in the control loop for the x-ray tube voltage. There is a program storage in which an optimum d.c. voltage for the inverter input is programmed for each pair of settings of x-ray tube voltage and current. There can be a function generator present which before the start of the radiograph supplies a control signal corresponding to an inverter input voltage lying a predetermined amount above the respective programmed value. The inverter input voltage may be regulated by a feedback control loop, and the set point value from program storage may be temporarily increased by the function generator at the start of a radiograph.

X-Ray diagnostic generator with an inverter supplying the high-tension

In the exemplary embodiment, in order to obtain a signal corresponding to the x-ray tube voltage, a voltage divider is connected in parallel with the x-ray tube whose resistances are bridged over by capacitances. The resistances of the voltage divider are applied in thick film technique in the form of windings on the one side of a substrate. On the other side of the substrate, conductive layers are applied of which each capacitively bridges over a portion of the windings.

X-ray diagnostic generator comprising means for obtaining a signal

One diode each is connected in antiparallel fashion to each load thyristor, said diode being a component of a commutation installation for the corresponding load thyristor. The commutation installation manifests an LC-series oscillatory circuit dimensioned for the specified load current and, for each load thyristor, a controllable commutation thyristor connected to a control circuit. Each commutation thyristor forms a closed circuit with the LC-series oscillatory circuit and its diode. One saturable choke each is connected in series with each thyristor and each diode. One RC-element each is connected in parallel with each thyristor and each diode, and saturation means are present for the chokes associated with the load thyristors. The inverter load may be the high voltage transformer of an x-ray generator.

Inverter comprising at least two controllable load thyristors

The disclosure relates to an inverter comprising at least two controllable load thyristors which connect a load alternately with the poles of a feed d.c. voltage source. There is connected in parallel with each load thyristor one diode each which is a component of a commutation installation. The commutation installation manifests an LC-series oscillatory circuit dimensioned for a specified load current, and, manifests, for each load thyristor a controllable commutation thyristor which forms a closed circuit with the LC-series oscillatory circuit and its diode. The LC-series oscillatory circuit is connected to an auxiliary d.c. voltage source of a constant voltage via a reloading circuit.

The disclosure relates to an inverter comprising at least two controllable load thyristors. One diode each is connected in antiparallel fashion with each load thyristor, which diode is a component of a commutation installation for the corresponding load thyristor. The commutation installation manifests two LC-series oscillatory circuits, which are dimensioned for two different load currents. There is present for each LC-series oscillatory circuit one pair each of commutation thyristors. The two commutation thyristors of one of the two pairs, respectively, are alternately ignited such that, during the commutation of the load thyristors the commutation current can flow in a low impedance circuit.

In the illustrative embodiment, the feeding of the high voltage transformer proceeds from an inverter which is connected to a dc voltage source. The inverter output frequency is adjusted in dependence upon the selected x-ray tube voltage such that as the x-ray tube voltage is reduced, the inverter frequency is correspondingly reduced.

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Uttenreuth, Germany

Werner Kuehnel