摘要:
An X-ray diagnostic apparatus having an adjustable mAs-relay for determining the exposure time. The adjustable mAs-relay is used for determining the exposure time, wherein the X-ray tube voltage and the X-ray tube current are varied in conformance with the fluctuations of the voltage supply. An operational amplifier may be employed, whose characteristics may, in a simple manner, be coordinated with the desired cycle of the mAs-product, in dependence upon the voltage supply. Additional auxiliary components for the voltage supply correlation are not required in the inventive arrangement.
摘要:
An X-ray diagnostic apparatus in which the X-ray tube voltage is regulated through intermediary of the X-ray tube current. In the apparatus, a regulator is situated within a regulating circuit for the effective value of the filament current of the X-ray tube, and influences the effective value of the filament current for the purpose of correlating the actual value with the reference value which has been determined through the preset X-ray tube voltage. In the inventive X-ray diagnostic apparatus, on the one hand, the actual value of the X-ray tube voltage is compared with a reference value, and the filament current is influenced for the purpose of correlating the actual value to the reference value. Furthermore, the filament current which is required for a predetermined reference value of the X-ray tube voltage is also maintained constant preceding the beginning of an exposure so that, at the initiation of an exposure, the filament current already lies at least near to the correct value. Deviations of the X-ray tube voltage from the correct value are thereby smaller than in prior art apparatus.
摘要:
A dental apparatus for x-ray diagnosis comprises a unit, which includes an x-ray tube and a film holder and is adapted to rotate around a vertical axis, and a support for the head of a patient disposed between the x-ray tube and the film carrier. The apparatus produces general tomograms with a radiographic recording time which is predetermined by a timer mechanism of the x-ray tube/film carrier unit, and by at least one further recording value which is adjustable by a regulating device to provide a nominal or reference recording value. The unit further comprises an x-ray detector disposed on the film carrier in a position in which the detector receives at least the x-ray radiation penetrating the jaw of the patient during the entire duration of an x-ray recording, during which period the detector supplies an electrical signal corresponding to the x-ray dose output. The detector and the regulating device are connected to an x-ray dose output regulator so as to provide automatic exposure such that the adjustable recording value is related to the output signal of the x-ray detector, whereby the x-ray dose output is adapted to a desired value resulting in an optimal exposure of the film. The regulating device for the nominal value for the output dose regulator is associated with a transmitter for transmitting an electrical signal related to the speed of transport of the film such that the nominal value is adjusted to be a function of the transport speed of the film.
摘要:
An exemplary embodiment comprises an exposure unit including an X-ray tube and a cassette holder rotatable about vertical axes and between which the head of the patient is disposed. A radiation detector is disposed at the cassette holder for supplying an electrical signal corresponding to the dose rate when it is struck by X-rays and being interconnected with an X-ray tube voltage controller and a dose rate regulator in such manner that the X-ray tube voltage is influenced by the output of the radiation detector to control the dose rate to a value producing an optimum film blackening. A function generator determining the speed of the exposure unit is provided in which a speed curve is stored given which the radiation dose influencing the film is approximately constant.
摘要:
In the illustrated embodiments, a rotary position encoder is manually positioned to select any of a set of x-ray exposure times to be used in making medical x-ray photographs. In one form, the encoder output selects a code word from a read only memory, and a comparator ends the timing cycle when a counter reaches a count value corresponding to the active code word. The pulse generator supplying input pulses to the counter, rather than operating at a constant rate, may be controlled so that the pulse count per unit time corresponds to a specified mAs-product, an x-ray tube being switched off when a selected count value (corresponding to a desired mAs-product) is reached.
摘要:
A time switch device for X-ray diagnostic apparatus, in particular for the preparation of tooth or dental exposures, including a knob for the setting of the exposure periods and which has a time scale on a scale carrier associated therewith. The knob has associated therewith a symbol carrier which, in the displacement direction of the knob, is adjustable relative to the knob and to the time scale, on which there are drawn the symbols of the objects which are to be X-rayed at such a spacing relative to each other whereby, upon the setting of one symbol on the exposure period associated therewith, the other symbols are then located opposite to the exposure periods which are associated therewith.
摘要:
An X-ray diagnostic apparatus for X-ray exposures, having preset X-ray tube voltage and current values, and a preset exposure time and, more particularly, to an apparatus of this type which includes a plurality of filters in conformance with an exposure program for the X-radiation adapted to be selectively employed in coordination with a particular exposure object.
摘要:
The invention concerns a dental X-ray diagnostic unit for panoramic planigraphy, with a radiation source, an X-ray film cassette that is moved during the exposure in relation to the radiation source, with an adjusting mechanism to move the radiation source and the cassette around the object, and with a slit stop located in the radiation path between the radiation source and the cassette. For a given exposure process, the time sequence of the dosage from the radiation source can be predetermined by a control apparatus.
摘要:
A dental x-ray diagnostic installation has an exposure unit consisting of an x-ray tube and a cassette holder for generating a dental x-ray exposure. The exposure unit is rotatable about a patient's head by a motor. A radiation detector is attached to the cassette holder which supplies an electrical signal corresponding to the radiation dose rate to a dose rate regulator which in turn operates a voltage control unit which sets the level of high voltage supplied to the x-ray tube such that the dose rate of the radiation emitted by the x-ray tube is maintained at a value for producing an optimum film exposure. A range adjustment for the x-ray tube voltage is externally selected and limits operation of the voltage control unit such that if the dose rate regulator supplies a signal to the voltage control unit requiring a voltage which exceeds the set limit, the voltage control unit is inhibited and instead the motor speed is adjusted to maintain the optimum exposure.
摘要:
An X-ray installation particularly adapted for dental diagnostic use wherein the radiating anode is disposed adjacent the remote end of a tube projecting from a cathode housing. The anode emitts radiation in substantially all directions and the tube has a length sufficient to be inserted into the patient's mouth. The tube containing the anode is equipped as desired with a radiation absorbing cap which in one instance limits radiation emission through a cap aperture for filming from within the patient's mouth and in a second instance comprises a slip-on cylindrical tube having a focusing opening at an axial end thereof for directing radiation to a specified area of the mouth from externally of the mouth.