Abstract: A system includes a generator configured to output at least one voltage level and an x-ray source configured to generate x-rays directed toward an object. The system includes a module coupled to the output of the generator and to an input of the x-ray source and configured to switch or assist in switching an output to the x-ray source between a first voltage level and a second voltage level.

Abstract: An imaging-condition setting part that sets a plurality of CT-image imaging conditions, including an electric amount for driving and controlling an X-ray tube during CT imaging, based on a scout image that has been imaged by irradiating X-rays from the X-ray tube, to a subject on a top board, that has been stopped at least one of said first position and said second position; and a calculating part that judges whether there are any detection elements that are expected to detect an X-ray dosage exceeding a predetermined value and outputs the judgment result when the X-ray tube is stopped at least one of the first position and the second position relative to the subject on the top board and X-rays are irradiated from the X-ray tube through driving and controlling based on the electric amount.

Abstract: The present invention provides an X-ray CT apparatus capable of obtaining each tomographic image indicative of X-ray tube voltage dependent information of a subject with the optimum image quality by less reduced exposure. The X-ray CT apparatus includes device for setting a plurality of X-ray tube voltages and sets imaging conditions used in the photography using the respective X-ray tube voltages in such a manner that respective image noise of tomographic images photographed at the X-ray tube voltages become substantially identical to one another. The setting of the imaging conditions is the setting of X-ray tube currents. The X-ray tube currents are set based on geometrical characteristic amounts of the subject determined from each scout image in such a manner that the respective image noise of the tomographic images photographed at the plurality of X-ray tube voltages become substantially identical to one another.

Abstract: There are provided an X-ray generating apparatus capable of switching X-ray beams of high energy and low energy to each other at high speed, and an X-ray CT apparatus capable of performing high-speed and high-quality multi-energy imaging by using the same. The X-ray generating apparatus is constructed by an X-ray tube 9 having two anodes 200a, 200b, a rotational anode 204 for radiating X-ray from an X-ray focal point by electron beams emitted from filaments of these cathodes, and two grid electrodes 202a and 202b for controlling emission of the electron beams, a tube voltage generator 9a and a tube voltage controller 9d1 for controlling an X-ray condition, a filament heater 9b and a tube current controller 9d2, a grid voltage generator 9c and a grid opening/closing controller 9d3, and a grid switching unit 9e. High energy X-ray and low energy X-ray are switched and emitted to an examinee every adjacent projection angles, thereby collecting projection data.

Abstract: In the radiographic apparatus of this invention, a composite image generating device generates a composite high-voltage/low-voltage image for every time of the same high voltage/low voltage based on a plurality of high-voltage/low-voltage images successively acquired by a high-voltage/low-voltage image acquiring device. Based on the composite high-voltage/low-voltage image generated by the composite image generating device, a subtraction processing device carries out a subtraction process concerning high-voltage images and low-voltage images, to acquire subtraction images. Thus, a mistake by arithmetic processing is made inconspicuous without causing a dose shortage.

Abstract: A system is provided, which includes a rotatable gantry for receiving an object to be scanned. The system includes an x-ray source for projecting x-rays of two different energy levels towards the object and also a power supply, which energizes the x-ray source to two different voltage levels at a predetermined rate for generating x-rays at two different energy levels. The power supply in the system includes a fixed voltage source to input a voltage to a switching module with number of identical switching stages. Each stage in the switching module consists of a first switch, which charges a capacitor in a conducting state and output a first voltage, a second switch, which connects the fixed voltage source and the capacitor in series to output a second voltage in a conducting state and a diode which blocks a reverse current from the capacitor to the power supply.

Abstract: In the X-ray CT apparatus of the present invention, the setting device sets X-ray irradiation condition candidate by at least one combination of a tube current and tube voltage for power to be supplied to the X-ray source by the use of an X-ray absorption coefficient of said scanning subject site of the object, and the control device makes the display device selectably display each of the set X-ray irradiation condition candidates which is provided for a diagnosis of a requested tissue of the object, to take control such that a tomographic image of the object is taken according to the selected X-ray irradiation condition candidate. According to the X-ray CT apparatus of the present invention, it is possible to set a scanning condition in view of absorption or transmission of X-rays specific to and different among each tissue of an object.

Abstract: An apparatus for use in a radiation procedure includes a radiation filter having a first portion and a second portion, the first and the second portions forming a layer for filtering radiation impinging thereon, wherein the first portion is made from a first material having a first x-ray filtering characteristic, and the second portion is made from a second material having a second x-ray filtering characteristic. An apparatus for use in a radiation procedure includes a first target material, a second target material, and an accelerator for accelerating particles towards the first target material and the second target material to generate x-rays at a first energy level and a second energy level, respectively.

Abstract: A system, a processor, and a method for tracking a focus of a beam are described. The method includes determining a plurality of intensities corresponding to a plurality of voltages, and applying a first voltage of the plurality of voltages corresponding to a maximum intensity of the plurality of intensities during a scan.

Abstract: The present invention is directed to a networked scanner environment wherein each scanner is communicatable with one or more databases configured to store data associated with previously executed imaging sessions. The one or more databases may be queried by a user to determine, based on a set of user inputs, an historical evaluation of the prior imaging sessions conducted in accordance with scan parameters similar to the scan parameters of an imminent imaging session. The present invention includes a global database that is accessible by a series of remotely located imaging systems as well as includes one or more databases particular to a specific treatment facility housing one or more imaging scanners. The present invention is also applicable with a stand-alone imaging system having a database local to that particular imaging system for storing and accessing data associated with imaging sessions conducted on that particular imaging system.

Abstract: A system includes a generator configured to output at least one voltage level and an x-ray source configured to generate x-rays directed toward an object. The system includes a module coupled to the output of the generator and to an input of the x-ray source and configured to switch or assist in switching an output to the x-ray source between a first voltage level and a second voltage level.

Abstract: Methods for determining and displaying x-ray radiation generated by a radiographic device may include storing in a memory a plurality of tables that correlate voltage and current values of an x-ray tube to a predicted radiation rate for a given radiographic device. Actual or approximate voltage and current values are then obtained from an operating x-ray tube. Based on these values, a predicted instant (or “dynamic”) radiation late is selected from one of the stored tables and is displayed to the practitioner. In addition, the method may approximate an accumulated radiation dose by measuring the time periods over which predicted radiation rates are generated and calculating a running total. Apparatus for conducting such methods is also disclosed.

Abstract: A voltage divider of a voltage generator is provided. The divider comprises an input terminal opposite an output terminal, a measurement resistor electrically connected in series between the input terminal and the output terminal, a footer resistor electrically connected in parallel between the output terminal and electrical ground, and a footer capacitor electrically connected in parallel between the output terminal and electrical ground. A value of the footer resistor is at least a magnitude smaller relative to a value the measurement resistor. The divider further includes a reactive bypass component having a first end electrically connected in parallel to the measurement resistor.

Abstract: An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 260 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.

Abstract: A voltage divider of a voltage generator is provided. The divider comprises an input terminal opposite an output terminal, a measurement resistor electrically connected in series between the input terminal and the output terminal, a footer resistor electrically connected in parallel between the output terminal and electrical ground, and a footer capacitor electrically connected in parallel between the output terminal and electrical ground. A value of the footer resistor is at least a magnitude smaller relative to a value the measurement resistor. The divider further includes a reactive bypass component having a first end electrically connected in parallel to the measurement resistor.

Abstract: A method and system is presented in radiography for optimizing image quality of an object (e.g. an anatomical region of a patient), while minimizing the radiation dose to the patient. X-ray exposure parameters, such as operating voltage (kVp), operating current (mA), focal spot size, and soft x-ray filter combination, are dynamically controlled during the x-ray exposure. During at least two different sampling intervals and at two different kVp levels, x-rays are passed through the object, and detected by sensors located between the object and the image plane. After the last sampling interval, the sensor output signals and the measured thickness of the object are used to evaluate the optimal settings for the x-ray exposure parameters. The x-ray exposure parameters are set to these optimal settings for the remainder of the exposure period.

Abstract: An X-ray device having an X-ray source, a high voltage generator supplying power to the X-ray tube and an inverter to generate, at the output end, an AC input voltage for the high voltage generator is disclosed. Provision is made therein for a resonance network to be formed between the inverter and the high voltage generator. This allows transmission of the AC input voltage with low power dissipation and low radiation levels. It also achieves spatial separation of the inverter from the high voltage generator and the X-ray source.

Abstract: An imaging tube (30) includes multiple high voltage elements (64). A voltage-clamping device (70) is coupled between the high voltage elements (64) and prevents the occurrence of overvoltage transients in the minor insulation of an imaging tube (30).

Abstract: An X-ray generator of this invention has an X-ray monitor that monitors a state of an X-ray emitted from a target. Hence the state of the X-ray can be monitored in real time to maintain the X-ray in a constant state. The X-ray monitor is positioned off the path on which an X-ray transmitted from a first exit window travels. Hence, when the X-ray is emitted from the first exit window to an object to be inspected, the X-ray monitor does not obstruct the approaching of the object to the first exit window. This makes it possible to acquire X-ray images of high magnification.

Abstract: A maximum tube voltage value setting module 240a, a warming-up module 240b, a limit tube voltage control module 240c, a limit tube current control module 240d and a focus grid electrode control module 240e of an operation program 240 which respectively correspond to different maximum tube voltage values are stored in storage sections 32a-e of an X-ray tube control apparatus 3. When the maximum tube voltage value of an X-ray tube 1 is changed, an extraction section 34 extracts each module of the operation program 240 which corresponds to the maximum tube voltage value after being changed from the storage sections 32a-e. A communications section 36 sends the operation program 240 comprised of each extracted module to an X-ray tube controller 2 and overwrites it in a memory section 24.

Abstract: Circuit arrangements and methods are disclosed for providing means of driving a grounded anode triode X-Ray tube using one isolation transformer, providing both filament power and controllable grid drive without the need for optical isolation devices. Applications of this design include fast X-Ray imaging such as inspection equipment and systems, which require rapid control of X-Ray intensity. Grounding the anode in X-Ray tube systems is usually done for thermal considerations and therefore requires that the filament and grid to be floating at an extremely large negative potential, usually over 100 kVDC. Isolation transformers are required to provide power to the filament and grid. In this invention, both AM and FM signals are coupled through one isolation transformer. The AM waveform provides controllable power to heat the filament while the FM signal, adjusted in magnitude by a filter arrangement, rectified and smoothed in waveform, provides power for the grid.

Abstract: A radiation detector includes radiation detection elements for detecting radiations which have penetrated an object as electric signals, with the elements arranged in a two-dimensional array, and an image display controller for producing a radiation image of the object detected as the electric signals with the radiation detector as continuous images including a plurality of frames. The image display controller switches a tube voltage of a radiation source for emitting the radiations between a first voltage at a time of producing odd images and a second voltage at a time of producing even images and controls a display device to continuously display a plurality of processed images as a dynamic image. Each of the processed images are obtained by performing a subtraction process between an odd image of the odd images and an even image of the even images, wherein the even image is derived in succession to the odd image.

Abstract: A multiple energy x-ray source capable of rapidly generating and delivering x-rays in the form of successive pulses that alternate between at least two different energy levels, as well as a multiple energy x-ray inspection apparatus for inspecting moving objects that employs such a multiple energy x-ray source, are provided. The inventive x-ray source facilitates the use of differential absorption characteristics as a means for distinguishing materials contained within objects during a moving inspection.

Abstract: An invention related to an X-ray device for the generation of brief X-ray pulses comprising an X-ray tube having a thermionic cathode and an anode and an X-ray generator having a first circuit for the generation of a high-voltage pulse which is applied to the anode for the generation of the X-ray pulse. The X-ray generator further comprising a second circuit by which a low voltage is continuously applied to the anode which pre-heats the X-ray tube and is at most sufficient for the generation of low-energy X-radiation. The first circuit can have a high-voltage power supply unit which charges a high-voltage capacitor which can be applied to the anode via a high-voltage switch. The first circuit can be a Marx generator. There may be only one power supply, which both generates the continuously low voltage and also drives the Marx generator for the generation of the high voltage.

Abstract: A current feedback circuit in a dental imaging apparatus, which measures the x-ray tube current produced by the x-ray filament. During preheat, when the tube current is sensed to be appropriate for production of a constant rate of electrons, preheat is stopped, and diagnostic radiation emission begins. This circuit eliminates a fixed amount of preheat pulses which contribute unusable radiation during preheat of the filament in prior art systems.

Abstract: The invention relates to a method of controlling an X-ray apparatus containing an X-ray emitter. Control means for the X-ray apparatus are provided with exposure time correction data for given mains voltages and the current mains voltage is measured before and/or during exposure and the exposure time is corrected in accordance with the correction data, and to an X-ray apparatus for carrying out said method.

Abstract: In a method to detect the pressure in an x-ray tube having a cathode of the x-ray tube that is heated with a heater current, and wherein electrons are accelerated between the cathode and an anode by an applied x-ray tube voltage, the heater current is measured, a tube current corresponding to the tube -ray voltage is measured, the difference between the measured heater current and the measured tube current is determined or the temporal change of the measured heater current or of the measured tube current is determined, the difference or the temporal change is compared with predetermined calibration values, and a value representing the pressure in the x-ray tube is determined from the comparison.

Abstract: An X-ray generator comprises a cathode electrode (15), a grid electrode (17) for controlling an electron beam (e) generated by the cathode electrode (15), a focus electrode (18) for focusing the electron beam (e), and an anode target (14) for emitting X rays by the collision of the electron beam (e). A bias voltage (Vb) is impressed between the cathode electrode (15) and the grid electrode (17) from a bias voltage generating section (20). A tube voltage (Vt) is impressed on the anode target (13) from a tube voltage generating section (19). A voltage dividing section (31) divides the tube voltage (Vt) to generate a focus voltage (Vf). The effect of a variation in voltage on the formation of a focal point of the electron beam is suppressed by impressing such a focus voltage (Vf) on the focus electrode (18).

Abstract: The conventional high voltage elements (1, 8) constituting it are located in such a way that the ground level (2) is situated in the central zone and from this zone the negative potential progressively increases towards one of the ends (3) while the positive potential progressively increases towards the opposite end (4). It is preferably applicable to radiogenic vessels (9), which also present the particular feature that all the elements constituting them present a voltage distribution identical to that of the transformer, in order to establish equipotential lines that do not require the incorporation of insulating elements, and which also enable the elements to be positioned very close to each other in such a way that the volume, its weight and its cost are considerably reduced.

Abstract: A system and method of diagnostic imaging with reduced x-ray exposure to the scan subject during scanning includes acquiring a set of cardiac signals or other motion (cardiac mechanical motion or respiratory motion) related signals and determining and imaging profile therefrom. Pursuant to the imaging profile, voltage applied to an x-ray source is modulated to provide an energizing voltage during primary data acquisition stages and a reduced voltage during secondary or non-data acquisition stages. Voltage modulation repeats until sufficient data for image reconstruction has been acquired.

Abstract: The voltage applied to a first grid electrode 71 of an X-ray tube 11 by a grid voltage control section 110 is controlled with reference to a predetermined negative voltage from a negative voltage generating section 112 when an object 5 to be inspected does not exist in an imaging area (irradiation area of an X-ray from an X-ray source 1) so that the pulse outputted from a pulse generator 105 is in its OFF state, and is controlled with reference to a reference positive voltage from a reference voltage generating section 115 when the object 5 to be inspected exists in the imaging area in the X-ray image intensifier 2 (irradiation area of the X-ray from the X-ray source 1) so that the pulse outputted from the pulse generator 105 is in its ON state, whereby both of the cutoff voltage and grid operating voltage are applied in a stable state.

Abstract: A circuit arrangement for generating an X-ray tube voltage is described, wherein a switching device, connected downstream of a voltage controller (Gsu) and a oscillating current controller (Gri), operable to compare a first controlling variable value (Yu(t)) and a second controlling variable value (Yz(t)) and is operable to send the lesser of the first and second controlling variable values (Yu(t) and Yz(t) onward as a resultant controlling variable value (Y(t)) to the inverse rectifier circuit (Gsi).

Abstract: An X-ray generator 1 includes an X-ray tube 11 having a cathode portion 16, a grid electrode 15 and a target 22, a voltage controller 27 and 32 for controlling voltages to be applied to the cathode portion 16 and the grid electrode 15, and switches 33 and 34 for operating ON and OFF of the X-ray generator 1 and of X-ray emission. The voltage controller 27 and 32, based on an ON-signal for the X-ray generator 1 and an OFF-signal for the X-ray emission, applies a positive standby voltage Vf1 to the cathode portion 16 and applies a negative cutoff voltage Vc1 to the grid electrode 15. Moreover, the voltage controller 27 and 32, based on the ON-signal for the X-ray generator 1 and an ON-signal for the X-ray emission, applies a cathode operating voltage Vf2 which is higher than the standby voltage Vf1 to the cathode portion 16 and applies a grid operating voltage Vc2 which is higher than the cutoff voltage Vc1 to the grid electrode 15.

Abstract: A circuit arrangement for generating an x-ray tube voltage is described, comprises an inverse rectifier circuit (Gsi) for generating a high-frequency alternating voltage, a high-voltage generator (Gsu) for converting the high-frequency inverse rectifier into a high voltage for the x-ray tube, and a voltage controller (GRU), which based on a deviation of an actual x-ray tube voltage (VU(t)) from a set-point x-ray tube voltage (WU(t)) generates a first controlling variable value (YU(t)) for a controlling variable for the inverse rectifier circuit (Gsi).

Abstract: A method described includes positioning an x-ray emitter at a treatment area, where the x-ray emitter is connected to a cable, setting a voltage source at a source voltage, and measuring a current through the x-ray emitter. The method may include comparing a current flowing through the emitter with a limit and a low limit. The method further includes increasing the source voltage if the current is higher than the high limit. The method includes determining the high limit and the low limit based on the source voltage and the desired radiation. An apparatus of the invention includes an x-ray emitter with a voltage source and a current sensor. The apparatus may include a current comparison device for comparing the measured current with a high limit and a low limit, and further include a voltage source control. A current integrator for integrating a current from the x-ray emitter may also be included.

Abstract: The present invention, in one form, includes methods and apparatus for reducing the x-ray dosage to a patient in a medical imaging system. In accordance with one embodiment of the present invention, a switching unit, or circuit, is coupled to a x-ray tube and a power supply to control the emission of x-ray beams from the x-ray tube. The switching unit is configured to alter a voltage and current signal applied to the x-ray tube control grid so that the magnitude of the x-ray beams is modified, or altered. By utilizing the switching unit the patient x-ray dosage is reduced and the magnitude of the x-ray beams may be configured to match the requirements of the application.

Abstract: A compact x-ray source and assembly is disclosed. The x-ray source is configured to operate without the need of a transformer within the x-ray source. Due in part to the elimination of components, and further due to the unique assembly of the x-ray source, the x-ray source is compact and can fit beneath, rather than above an x-ray transparent patient table. Accordingly, the x-ray source projects x-rays in an upwardly direction toward the object to be imaged. As a result of the unique configuration of the x-ray source, scattered x-rays are directed away from upper body areas of attending medical staff and radiation to the sensitive tissue of a patient is reduced.

Abstract: An X-ray apparatus, includes a power supply section for powering an X-ray tube (4) with a high-voltage transformer (3) which has two groups of primary and secondary windings provided on the same transformer core, the coupling between the primary windings (16, 26) belonging to different groups being weaker than the coupling between primary and secondary windings (for example, 16, 31) belonging to the same group, the primary windings of the two groups being connected to two inverters (1, 2) which operate at the same frequency. Control of the power at the secondary side is improved in that the inverters are operated at a fixed frequency and with a duty cycle which can be independently controlled.

Abstract: An x-ray tube of a CT scanner is powered by a high-voltage power supply (26). The high-voltage power supply includes a plurality of sections (102) each having three straight-up transformers (48) which receive three 120.degree. phase shifted alternating current components as inputs. The straight-up transformers perform a direct voltage transformation with single or multiple transformers and with no capacitive multipliers. Each straight-up transformer has a primary winding (T1) and two secondary windings (T1-A, T1-B). The secondary windings are connected together in delta and wye configurations (84). The alternating current components have their voltage boosted and are rectified and summed to form a high-voltage output that is substantially ripple-free. A pulse-width modulated converter (34) generates a conditioned output current from an inputted direct current.

Abstract: Disclosed is a three-value power supply device, adapted for supplying developing bias voltages to a copying machine. The device comprises a positive high voltage source, a negative high voltage source, first and second high voltage transistors serially connected between the positive and negative high voltage sources, with an output terminal connected to the junction point between two transistors, and a timing controller for selectively turning on and off the two transistors.

Abstract: This invention aims at providing an X-ray apparatus having a stable X-ray output. Since the focus electrode of the X-ray tube of the X-ray apparatus according to this invention maintains a ground potential, the focus diameter of electrons bombarded against a target becomes constant. Hence, the X-ray output emerging from an exit window is stabilized. Since the potential ratio of a cathode to the target is always constant, the electric field distribution between the cathode and the target is stabilized, thereby stabilizing the X-ray output emerging from the exit window.

Abstract: A high-voltage power supply and regulator circuit for an X-ray tube which utilizes solid state switching devices and provides protection against failure of the switching devices due to transient voltage spikes. The high-voltage protection circuit includes an inductor intercoupled with a high-voltage clamp, such as a series of solid state current conducting devices in parallel with the inductor. The protection circuit further includes a diode connected in parallel with the capacitor for preventing the voltage across the regulator circuit from reversing polarity. A shielded voltage divider may further be provided to accurately measure the voltage output and produce feedback control signals. Still further, a discharge module may be provided on high-voltage cables connecting the regulator circuit to the X-ray tube in order to discharge any capacitive voltage remaining on the cables between pulses, in order to eliminate any tail on the output waveform.

Abstract: An X-ray computed tomography apparatus includes a rotating frame section, an X-ray generating system mounted on the rotating frame section, electric power transmission means constituted by a slip ring and a brush and designed to supply electric power to the X-ray generating system, and a detection means for detecting an electric power supply state in the electric power transmission means.

Abstract: A CT system includes a pair of detectors in its detector array which measure x-ray intensity from a source after passing through a differential x-ray filter. The ratio of the signals produced by these two detector elements are input to a KV calculator which produces a signal indicative of x-ray tube voltage.

Abstract: In an x-ray diagnostics installation for mammography, an automatic setting of the optimum beam quality ensues in combination with transparency matching. A set of exposure parameters corresponding to different thicknesses of the examination subject is stored in a memory (reference values). At the beginning of an x-ray exposure, a comparator compares the transparency signal (actual value) to the exposure parameters (reference value) interrogated from the memory dependent on the current thickness of the examination subject, and influences the x-ray tube voltage for the purpose of a rated/actual value comparison without interrupting the exposure.

Abstract: Apparatus for supplying operating power to an X-ray generating source, wherein the source sends a radiation signal to a patient and a portion of the signal which passes through the patient is utilized to produce an image of the patient, the apparatus comprising a power supply which includes a mechanism for receiving a low-voltage input signal and a voltage transforming and combining mechanism for producing a high voltage signal; and a mechanism for monitoring the high-voltage supply signal, a mechanism for receiving the supply signal and regulating the duration or amplitude of the supply signal to produce a high-voltage regulated output signal for operating the X-ray generating source, and a mechanism for receiving X-ray radiation which has passed through a patient and generating a feedback signal representative thereof which enables automatic control of the amount of X-ray radiation received by the patient.

Abstract: An interactive system for producing acceptable quality fluoroscopy images determines X-ray tube photon count and voltage while minimizing X-ray radiation dosage to a subject. Parameters of the subject and the type of image to be produced are provided to the system. X-ray tube voltage U and photon count Q are initialized at a fraction of conventional values for a portion of a subject to be imaged. An image is created and sectioned into rectangles. Rectangles having the greatest and least gradient values are used to determine variances indicating signal and noise power respectively. Images are produced and adjusted until the maximum transmitted power is reached, or the signal-to-noise ratio does not increase beyond a quality increment. The process is repeated to optimize X-ray tube voltage. The X-ray fluoroscopy procedure is then performed with the optimum X-ray tube photon count and the optimum X-ray tube voltage thereby reducing X-ray dosage. The optimization is repeated periodically to readjust the system.

Abstract: A high-voltage power supply and regulator circuit for an X-ray tube which utilizes solid-state switching devices with feedback control for real time monitoring and protection against failure due to excess current or voltage spikes. The apparatus includes a DC supply circuit utilizing a first feedback control loop and silicon controlled rectifiers to regulate the output of a high-voltage transformer. The apparatus further includes a regulator circuit utilizing a second feedback control loop and a series of FETs to product a continuous or pulsed output of precise magnitude and phase. Shielded voltage dividers are provided to accurately measure the voltage outputs and produce feedback control signals. Discharge modules on the high-voltage cables connecting the power supply to the X-ray tube discharge any capacitive voltage remaining on the cables between pulses, so as to eliminate any tail on the output waveform.

Abstract: An X-ray imaging apparatus has a vacuum tube with an envelope that contains an anode, a cathode and a filament. A motor has a rotor mechanically connected to the anode inside the envelope and a stator on the exterior of the envelope. The vacuum tube and the motor are enclosed in an electrically conductive casing which are grounded. A grounded shield of a conductive material is placed between the stator and the envelope to suppress high voltage discharges within the envelope from producing currents in a winding of the stator. Low pass filters are placed in series with each conductor between the vacuum tube and a power supply to suppress radio frequency signals produced by the high voltage discharges from being carried over the conductors.

Abstract: A power supply (C) for an x-ray tube filament (10) selectively functions either as a constant voltage source (12) or a constant current source (14). A control circuit (A) includes a voltage controller (56) for enabling the power supply to operate as the constant voltage source in a first time period t.sub.1 to t.sub.2 during which filament temperature (40) is increasing toward a preselected filament operating temperature (42). Once the filament temperature has substantially reached its operating temperature at a time t.sub.2, a timer (52) enables a current control (84) which causes the power supply to supply a constant current across the filament.