Abstract: The invention relates to an X-ray device in which a set of exposure parameters is fetched from among a number of such sets stored in a first storage arrangement for APR X-ray exposures. The exposure parameters which result therefrom during the subsequent X-ray exposure and have possibly been modified by the user are stored in a second storage arrangement. The X-ray device includes means for evaluating the second sets of exposure parameters which are associated with the same first set of exposure parameters and for deriving therefrom a new set of exposure parameters which is stored in the first storage arrangement instead of the first set of exposure parameters and forms the basis for APR X-ray exposures from then on.

Abstract: A system and method of medical imaging is designed to reduce a patient's X-ray exposure during scanning. The system automatically generates a default noise index from a received set of scan parameter values that specifies a desired tube current of an X-ray source to use during the scanning of a patient. The default noise index can then be overridden to select a preferred noise index based upon a desired diagnostic quality for a particular volume of interest (VOI) and a diagnostic objective.

Abstract: A method and system for reducing radiation exposure from an imaging system including determining an entry location, operating the imaging system so as to cause the imaging system to emit radiation having a radiation intensity, controlling the radiation intensity in a manner responsive to the entry location so as to create image data and processing the image data so as to create processed image data. In an alternative embodiment, a medium encoded with a machine-readable computer program code for reducing radiation exposure from an imaging system, the medium including instructions for causing a controller to implement the aforementioned method.

Abstract: A method for controlling a computed tomography scanner for producing projections of a measurement object is proposed, in which the projections are used to create images of the measurement object. The method has comprises specifying a set-point value (&sgr;set-point) for a factor (&sgr;(I)) that is characteristic of a quality of the projections to be produced; determining an actual value of the factor (&sgr;(I)) that is characteristic of the quality of the particular projection produced by the computed tomography scanner between the productions of successive projections; and regulating the primary intensity (I0) of an X-ray source of the computed tomography scanner, between the productions of successive projections, such that the actual value for the characteristic factor (&sgr;(I)) of each of the projections produced by the computed tomography scanner is kept at the specified set-point value (&sgr;set-point). A computed tomography scanner that is suitable for performing the method is also disclosed.

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: An x-ray emitting system and method for administering a predetermined x-ray dose rate are provided. The system includes an x-ray emitter, a controller operably connected to the x-ray emitter, a current sensor operably connected to the controller, and a voltage sensor operably connected to the controller. The controller determines an actual dose rate based on a received current sensor signal and a received voltage sensor signal and adjusts a supplied voltage to allow the actual dose rate to match a predetermined dose rate. The method of operating a device for emitting x-rays includes: applying a voltage from a voltage source to the device, measuring current and voltage within the device, determining an actual dose rate based on the measured current and voltage, comparing a desired dose rate to the actual dose rate, adjusting the applied voltage, and matching the actual dose rate to the desired dose rate.

Abstract: A device for determining exposure values in an X-ray panoramic and/or cephalometric apparatus (20) for imaging patient's head (3). The apparatus comprises adjustable support means (11) provided with support elements (1a, 1b) with a variable spacing (W1) therebetween, and said support means being adapted for positioning against the patient's head prior to exposure. A sensor (2) is connected to said support elements and it provides an electrical output proportional to the dimension (W2) of the patient's head therebetween. An exposure control means (10) adjust the tube current and/or the tube voltage of the X-ray tube and/or the exposure time to be at one of a plurality of predetermined levels.

Abstract: An X-ray examination apparatus includes an X-ray source with a brightness control signal input, an X-ray image device for providing an X-ray image of an object to be imaged, X-ray absorption means between the X-ray source and the X-ray image device, a brightness control system coupled to the X-ray image device and the brightness control signal input in order to derive a brightness control signal from the X-ray image, and a detection means which is coupled between the X-ray image device and the brightness control signal input in order to exclude a degree of detected absorption from said brightness control signal caused by the absorption means present in the X-ray image. Direct radiation and absorption means (such as filters) in the detected absorption range in a histogram of pixels of the X-ray image are automatically excluded from the brightness control which is thus improved.

Abstract: The present invention, in one form, is a system which, in one embodiment, adjusts the x-ray source current to reduce image noise to better accommodate different scanning parameters. Specifically, in one embodiment, the x-ray source current is adjusted as a function of image slice thickness, scan rotation time, collimation mode, table speed, scan mode, and filtration mode. Particularly, a function is stored in a CT system computer to determine an x-ray source current adjustment factor so that the appropriate x-ray source current is supplied to the x-ray source for the determined parameters. After adjusting the x-ray source current, an object is scanned.

Abstract: The invention relates to an X-ray device which operates with only a single image detection device whose format corresponds to the maximum exposure format. In order to facilitate the adjustment of the exposure field for an exposure, a respective set of exposure parameters is stored in a memory for each of the various organs to be imaged; this set includes inter alia an adjustment value for the size of the exposure field for an exposure of the relevant organ. This adjustment value is fetched and the diaphragm unit is automatically controlled in such a manner that the fetched adjustment value is (pre)adjusted.

Abstract: An exposure management and control system and method for x-ray technique selection is provided. Optimal x-ray technique, which affects image quality, can be accurately predetermined to use for any application. A patient model is combined with a closed loop brightness control, using a parameter that does not affect image quality. This is used to create a control system that operates as a knowledge based control system. The x-ray system brightness control system comprises a first and second regulator. The first regulator is an image quality, or brightness, regulator. The brightness regulator can have multiple functions, such as peak mA control, power limiter, skin dose limiter, and an override function. The second regulator is a dose error regulator. The second regulator is independent of the first regulator, and cooperates with the first regulator to provide x-ray technique optimization independent of brightness control.

Abstract: A method for modulating the intensity of an x-ray beam in an x-ray inspection system so as to maintain the highest penetration power and optimum image quality subject to keeping the ambient radiation generated by the x-rays below a specified standard.

Abstract: 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.

Abstract: It is an object of the present invention to provide an x-ray diffractometer for measuring an x-ray diffraction pattern obtained by irradiating x-rays 6 to a sample 7, in which, even though irradiation/non-irradiation of x-rays 6 to the sample 7 are repeated, a target in an x-ray tube bulb 1 is not contaminated and a filament 3 is not thermally stressed, thus improving the practical lifetime of the x-ray tube bulb 1. To achieve this object, the x-ray diffractometer of the present invention is arranged such that x-ray irradiation/non-irradiation selecting means 17 is arranged to switch states of supply and non-supply of a tube voltage to the x-ray tube bulb 1, and that an x-ray generating power source device 11 comprises filament preliminary heating current supply means 16 for letting flow a preset current in the filament 3 of the x-ray tube bulb 1 in the state where a tube voltage is not supplied.

Abstract: An x-ray generator wherein the tube current is kept constant independently of the drop in the cathode temperature after the radiation is switched on has a control circuit for the tube filament current in which a correction value that corresponds to the drop in the tube current given constant filament current during the radiation phase due to the drop in temperature of the cathode is superimposed on the rated value of the filament current at the beginning of radiation.

Abstract: The present invention, in one form, is a system for modulating x-ray tube current as a function of gantry angle and slice location in a computed tomography system. In one embodiment, a desired noise level for a final image is selected, and a desired minimum x-ray photon reading and a desired average x-ray photon reading are identified to produce an image in accordance with the desired noise level. During scanning, actual x-ray photon readings are used with the desired average x-ray photon reading and the desired minimum x-ray photon reading to generate an x-ray modulating factor. This modulating factor is then used to modulate the x-ray tube current.

Abstract: A method for controlling output of an x-ray source to optimize x-ray energy arriving at an associated x-ray receptor during linear tomographic examination. The method comprises the steps of selecting tomographic sweep parameters, predicting a set of x-ray source control parameters based, at least in part, upon the selected tomographic sweep parameters, and controlling x-ray source output in accordance with the set of x-ray source control parameters to optimize x-ray energy arriving at the associated x-ray receptor. Apparatus for controlling output of an x-ray source is also disclosed.

Abstract: An X-ray system includes an X-ray generator for operating an X-ray tube (1) having a cathode which can be heated by a filament current (I.sub.h), a continuation (5, 57) which is operative in an exposure mode so as to boost the filament current to a boost value (I.sub.b), and a continuation which is also operative in the exposure mode so as to decrease the filament current and to switch on the tube voltage (U). The time elapsing until the start of exposure is reduced in that the X-ray generator has a special mode in which the filament current is boosted to the boost value (I.sub.b) while the tube voltage (U) is switched on, circuitry (4, 6) is provided for measuring the tube current flowing in the special mode. A memory (8) is provided for storing the temporal variation of the measured tube current, or a value (I.sub.cor) derived therefrom, and the control unit (5, 57) is operative for deriving the boost time from the temporal variation stored in the memory (8).

Abstract: An X-ray apparatus a includes a high-voltage generator (1) a combination of an X-ray tube (7) with an anode (13) and a cathode (15), connected in series with the X-ray tube, a series connection of a first resistor (9) and a control element (11) which acts as a variable resistance and has an anode (17), a cathode (19) and a control electrode (25), and a control circuit (27) which is suitable to generate a control voltage which is dependent on the electric voltage between the anode and the cathode of the X-ray tube and which appears at an output (33) which is connected to the control electrode of the control element, the arrangement being such that the voltage between the anode and the cathode of the X-ray tube is always substantially equal to a predetermined value, regardless of the current flowing through the X-ray tube.

Abstract: An x-ray CT system modulates x-ray tube current as a function of gantry angle to reduce the total patient dose without significantly increasing image noise. A modulation waveform is stored in a table as a function of gantry angle, and during a slice acquisition, values are periodically read from this table and employed to calculate tube current commands. Tube current is monitored and compared with the latest command to ensure the proper x-ray dose is applied.

Abstract: An automatic exposure control system which regulates the power supplied to an x-ray source of a tomographic apparatus is disclosed. The system includes an x-ray source movably opposing an ionization chamber with a sweeping mechanism and a control for controlling the mechanism. A microprocessor which receives an input reference voltage and combines the voltage with a signal generated by the control to thereby produce a reference signal. This reference signal is then compared with a signal detected by the ionization chamber to determine an output error signal. Power supplied to the x-ray source is then adjusted based on this error signal.

Abstract: A high voltage electronic tube comprises an electrode arrangement comprising an outer electrode formed by a cylindrical metal jacket, an inner electrode supported substantially centrally with respect to said outer electrode by an electrode support arranged in an insulating disc providing a vacuumtight closure for the tube and at least one intermediate electrode formed by a metal sleeve arranged concentrically between the outer and inner electrodes. From a high voltage supply circuit comprising an alternating current source and a multi stage voltage multiplier a ground potential is applied to the outer electrode and a high potential of a significant magnitude is applied to the inner electrode, whereas the intermediate electrode is connected to an intermediate stage of the voltage multiplier for receiving a potential of a magnitude between the potentials applied to the inner and outer electrodes.

Abstract: An x-ray CT system performs a multi-slice scan in which tube current is modulated to reduce the x-ray dose without increasing image noise. Scout data is acquired from which a relative attenuation function (RAF) is calculated to relate expected patient attenuation of the x-ray beam at each slice to a reference. Tube current commands (mA) for each slice are calculated from the RAF and used to acquire image data.

Abstract: A supply for a high bias voltage in an X-ray imaging system has an inverter and a voltage multiplier that produce an alternating output voltage in response to control signals. A voltage sensor produces a signal indicating a magnitude of the output voltage. A circuit determines a difference between the sensor signal and a reference signal that specifies a desired magnitude for the output voltage and that difference is integrated to produce an error signal. The error signal preferably is summed with a precondition signal that is an approximation of a nominal value for the signal sum and the summation producing a resultant signal. Another summation device arithmetically combines the resultant signal and the sensor signal with a signal corresponding to a one-hundred percent duty cycle of the inverter operation in order to produce a duty cycle command.

Abstract: An improved fluorescent x-ray instrument includes an x-ray tube for generating x-rays, with a control grid regulating the production of x-rays. An operator can set the voltage to be applied to the control grid, and a feedback system will set a desired voltage to the control grid. An operator will be provided an output signal representative of the monitor control grid voltage to enable the operator to determine the operative status of the x-ray tube.

Abstract: An X-ray diagnostic apparatus includes: an X-ray tube; an X-ray controller for controlling a dose of X-rays generated by the X-ray tube; an image intensifier for converting X-rays radiated by the X-ray tube and passed through an object to be diagnosed, into an optical image; an optical system through which the optical image is passed; an image forming device for transducing the optical image obtained through the optical system into electric signals, the image forming device being provided with Knee characteristics such that photoelectric transduction characteristics into the electric signals has a point of inflection beyond which gradient thereof is reduced; a memory device for storing the electric signals outputted by the image forming device; an image displaying unit for processing the electric signals of the memory device for display of diagnosis information of the object to be diagnosed; an interest region determining section for determining a region of interest with respect to the diagnosis information d

Abstract: A circuit arrangement for accurately measuring the x-ray tube current substantially eliminates measurement errors by taking the displacement current caused by the capacitance of the high-voltage cable into account in the measurement. A test voltage is taken across a precision resistor. Another voltage is tapped at a location which includes the high-voltage cable capacitance and is supplied to a status monitor which differentiates this voltage and generates a voltage signal which is superimposed on the test voltage for forming a current signal which accurately represents the x-ray tube current.

Abstract: An x-ray generator includes an x-ray tube voltage regulation system which automatically adapts to line impedance and fluctuations in the network voltage, so as to maintain the x-ray tube current at a maximum value. The x-ray tube current is set by the x-ray tube voltage, the x-ray tube current is regulated so that a maximally allowable line voltage drop is not upwardly exceeded. The x-ray tube current, consequently, always has its maximum value, given the prevailing circuit conditions, so that the tube power is also at a maximum value. The current is set so as to achieve a desired mAs product, which is in turn determined by the radiation dose which the operator desires.

Abstract: A current supply has a first voltage summing circuit with two inputs, one of which receives a signal that indicates a desired current level to be produced. A current source produces a current level at an output in response to a control signal received from the first voltage summing circuit. The current source output is coupled to a center tap of the primary winding of a transformer that has a capacitor connected across the end terminals of its primary winding. Separate transistors connect ends of the primary winding to a common node and a resistor couples the node to circuit ground. A sensor produces a voltage e.sub.i that is proportional to a magnitude of the current flowing through said capacitor. A second voltage summing circuit produces an output voltage e.sub.t equivalent to the sum of voltage e.sub.i and the voltage across the resistor and the output voltage e.sub.t is applied to the other input of said first voltage summing circuit.

Abstract: The disclosure relates to devices for supplying current to X-ray tube cathode filaments. The filament of a cathode is supplied with high-frequency current pulses given by a hyporesonant type DC/AC converter, the transistors of which are controlled by a regulation circuit. This regulation circuit carries out a high-frequency regulation.

Abstract: An exposure control circuit captures an X-ray generator exposure time for a master exposure and replicates that time for subsequent exposures in a series. In one preferred circuit an read counter bank counts down clock pulses during the master exposure time, and then this count is held and is used by a write counter bank which counts up during subsequent exposures. A control circuit controls loading an enabling functions of the read and write counters. For the subsequent exposures, an output relay circuit terminates the X-ray generator exposure when the write counter bank reaches a predetermined count. This arrangement is used favorably with digital subtractive angiography (DSA).

Abstract: A low-level, electron beam activated source of preselected or programmable duration and intensity x-rays. The source may be fully or partially implanted into, or surface-mounted onto a desired area to affect a preselected irradiated region. In medical applications, a method of treating malignant cells, such as tumors, in vivo, utilizing the apparatus described above.

Abstract: An x-ray diagnostics installation for mammography exposures has a radiation detector for making a radiation measurement used to calculate the average parenchyma dose. The radiation detector is disposed on the support table next to the measurement field in which the mammary gland is disposed, and supplies a signal to a computer corresponding to the measured radiation dose at the detector location. The computer is programmed with the dependency of the average parenchyma dose, with respect to the radiation dose at the location of the radiation detector, and thus the computer generates a value corresponding to the average parenchyma dose, obtained by direct measurement rather than by calculation.

Abstract: A protection arrangement for a high voltage tube includes a low inductance disk resistor connected in series with the anode of the tube. When an electrical discharge occurs within the tube, the increased anode current flows through the resistor which absorbs much of the potentially harmful energy surge. The resistor is a disk resistor comprising two counter-wound planar spirals of resistance wire electrically connected in parallel and counter-wound with respect to one another. Connection arrangements are provided to both electrically and mechanically connect the resistor to the high voltage tube.

Abstract: An X-ray inspection apparatus and method allow inspection of the contents of containers moving rapidly past an inspection station. The system includes an X-ray source pulsed by control logic, an image amplifier for converting an X-ray image of the container contents to a visible image and a solid-state camera for converting the visible image into video signals which are processed by a computer-controlled image processor. Clear images are produced of the contents of rapidly moving containers by pulsing the X-ray source. Control logic and a reject mechanism eject containers having foreign contaminants. Image illuminance stability is enhanced by feedback signals from the vision computer which operate a motorized camera lens.

Abstract: A head-activated fluoroscopic control which is characterized in a preferred embodiment by a continuous wave infrared transmitter located in a cartridge adapted for attachment to eyeglasses, a headband or other headpiece worn by a surgeon or attending physician and a detector or receiver tuned to the frequency of the continuous wave infrared transmitter for receiving a partially collimated infrared signal beam and activating a fluoroscope. The infrared transmitter emits the collimated beam and the beam is received by the receiver when the surgeon's head is turned toward the fluoroscope monitor upon which the receiver rests or in which the receiver is mounted, to facilitate selective operation of the fluoroscope during surgery.

Abstract: A pulsed precision x-ray source includes a miniaturized internally self-shielding x-ray tube and an integral generator contained in a hand-held housing for generating timed bursts of x-ray having regulated energy level. A control grid and focus electrode within the tube enable precise on-off control of an electron beam directed to an x-ray emitting anode. The integral generator system includes an elongated, U-shaped unitary, molded plastic block mounted in the housing and includes a high voltage transformer having primary and secondary annular windings encased in a transformer portion of the block defining a central opening outside of the block for receiving a transformer core therethrough and, a capacitor-diode voltage multiplier stack connected to the secondary winding and having a positive node connectable to the anode and a negative node connectable to the cathode.

Abstract: A voltage control (22) controls the voltage applied between an anode (12) and a cathode filament (14) of an x-ray tube (10). A filament control (16) controls the amount of current fed through the filament. A voltage controlled oscillator (40) and counter (42) monitor the magnitude, if any, of a tube current (24) flowing between the cathode and the anode to generate x-rays (26). A microprocessor (50) calibrates the filament current such that the filament current value stored in a filament current look-up table (122) for each selectable tube voltage and tube current combination actually produces the selected tube current. The filament current is initialized (60) to a small current value and progressively incremented (66) until a commencement of the tube current (24) is monitored (64).

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.

Abstract: A current detecting circuit for an X-ray tube is disclosed which includes a DC high voltage generating circuit connected across a filament and an anode of the X-ray tube and current detecting means connected in series in a filament circuit. The filament, which is at a high potential, receives a power from a secondary winding of an isolation transformer, which has sufficient dielectric strength to insulate a highest voltage generated by said DC high voltage generating circuit. A rectifier circuit is arranged to rectify a current fed from said secondary winding or another winding having same dielectric strength as that of said secondary winding, and said rectifier circuit supplies a power to a signal transmitting circuit. The signal transmitting circuit is energized, according to the current detected by said current detecting means, to transmit an output signal. The output signal is transmitted through electrically isolated transmission means to a signal receiving circuit, which is at a ground potential.

Abstract: The generation of excessive electron radiation is prevented in an apparatus which comprises an accelerator means for generating and accelerating electrons. The accelerator comprises an electron injector for emitting injector pulses, an electron gun for receiving the injector pulses, a waveguide receiving electrons from the electron gun and a high frequency source for supplying RF signals for the generation of an electric field for accelerating the electrons in the waveguide and generating the electron beam which has a predetermined intensity level according to the amplitudes of the injector pulses. A sensing means senses the amplitudes of the injector pulses and generates sensing signals. The amplitudes of the sensing signals are compared with predetermined reference voltage values and the generation of the electron beam is prevented if the amplitudes of the sensing signals exceed the predetermined reference voltage value.

Abstract: The brightness of an X-ray video image during fluorography is maintained at a substantially constant level by a control circuit which varies the X-ray dose in relation to changes in the average brightness of the X-ray image. Selected picture elements of the image which lie within a defined region in the image and which have a brightness above a given level are used to derive the average X-ray image brightness. The brightness of the selected picture elements are summed and the number of such picture elements counted. The summation of the brightness and the picture element count are both scaled by a factor of 2.sup.n to reduce the size of the numbers of the complexity of the averaging circuitry. The scaled brightness summation is divided by the scaled picture element count and the result is stored as the average X-ray image brightness.

Abstract: The invention concerns an X-ray tomograph device.This device makes it possible to obtain the image (1) of a plane cutting (2) of an object (3). In particular, it comprises an X-ray source (4) which supplies high energy pulses which traverse the object. At least one measurement detector small bar (10) receives the attenuated energy pulses which have traversed the object. A display and processing means connected to the detectors supplies the image of the cutting. These processing means include amplifier-integrator circuits (13) connected to the detectors (10) and to a computer (15) controlling the integration period of the detection pulses suplied by the detectors (10). The computer corrects the value of the amplitude of each detection pulse by talking account of an intermediate integration value so as to take account of the drag of each pulse and the stray current of each detector.

Abstract: An x-ray tube (A) is powered by a control circuit (C) for selectively irradiating a sheet of x-ray film (B). An operator selects the operating anode current mA for the x-ray tube, an exposure or dose value (preferably an mAs value), and a tube voltage kV on a keyboard (20). For a fixed operating voltage and selected mAs value, the film should be exposed to the same density regardless of whether a low mA and a long time or a high mA and a short time are selected. Particularly in single phase inverter control circuit and power supplies, the high current and short time exposure tend to be underdeveloped relative to low mA and long time exposures for the same mAs value. To standardize the exposure for any current and time combination of the selected mAs value, a look up table (60) is provided. The look up table is addressed by the selected kV, mA, and mAs values to retrieve an appropriate current boost value which boosts the actual current such that the film is exposed to the selected density.

Abstract: An X-ray imaging system includes an X-ray tube which emits X-rays that are converted to visible light image by an image intensifier. This system can be operated in either a fluoroscopic mode in which the visible light image is viewed by a video camera and displayed on a monitor, or a film camera mode in which the visible light image is recorded on film. The X-ray system is calibrated for a selected fluoroscopic dose rate by producing an exposure and sensing the current through a photocathode of the image intensifier. The actual dose rate is derived from the sensed photocathode current. The excitation of the X-ray tube is the adjusted until the actual dose rate is within a given tolerance range of the selected dose rate. The system parameters are then stored for use when the same dose rate is selected again. Parameters for other selectable fluoroscopic dose rates are calculated from the stored parameters. The dose rates for the film camera mode then are calibrated using a fluoroscopic mode exposure.

Abstract: An F-kV and an F-mA output from tube-voltage adjuster and tube-current adjuster, respectively, are supplied to exposure-rate controller. Controller compares an input entrance exposure rate determined by the F-kV and the F-mA with a preset exposure rate set in view of a patient's safety. When the former is equal to or less than the latter, controller supplies the input F-kV and F-mA to X-ray tube. When the former exceeds the latter, controller supplies an F-kV and an F-mA corresponding to the preset exposure rate to X-ray tube and a limit signal to auto-iris controller. X-rays output from X-ray tube are transmitted through patient to form an X-ray image. The X-ray image is converted into an optical image by image intensifier tube. After the light quantity of the optical image is reduced by auto-iris, the optical image is picked up by TV camera. TV camera outputs an image signal to TV monitor and brightness detector.

Abstract: The quality of x-ray images is significantly enhanced by adjusting the x-ray system operating parameters in real time during acquisition of x-ray data to take information about the part into account adaptively. X-ray energy, x-ray flux, and integration time can all by varied independently and in combination to improve the signal to noise ratio in the image. The x-ray data from a previous subsection of the image is processed to determine optimum system operating parameters for a next image subsection. x-ray tube voltage is adjusted to change x-ray energy and keep .alpha.L close to 2 over all image subsections. X-ray tube current is adjusted to change x-ray flux and data acquisition integration time is adjusted to keep the signal to noise ratio within limits.

Abstract: The tube current in an X-ray tube is controlled by a closed loop control circuit in which a tube current feedback signal is used to control X-ray tube filament current. The gain of the feedback loop is maintained substantially constant over a wide range of tube currents by inserting a signal proportional to the reciprocal of the tube current command.

Abstract: A filament current regulator for an X-ray generator includes a circuit which compares the actual X-ray tube filament current to a predefined filament current reference value. Another circuit is included which compares the actual X-ray tube excitation voltage, applied across the anode and to cathode of the tube, to a predefined reference voltage value. The regulator adjusts the filament current during a first time interval of an exposure based on only the filament current comparison, and during the remainder of the exposure based substantially on the excitation voltage comparison. The regulator apparatus also integrates the difference between the actual filament current and the reference current value over a given interval during the exposure. The integrated result is employed by the regulator to redefine the filament current reference value.

Abstract: A structure and method for providing optimum recording of X-ray images without need for experimenting to learn optimum X-ray tube voltage, current, anode focal spot size and exposure time. The method and structure of this invention sample the radiation passed through an object to be radiographed during a short portion of the total exposure time and adjust voltage, current and focal spot size so that the radiation delivered by the X-ray tube during the remainder of the exposure time will produce optimum contrast between structures within the object being radiographed, also optimum sharpness of the image and optimum darkening of a film, xerographic picture, fluoroscopic image, or other recording medium. The method and structure of this invention account for variations in absorption coefficient between one object to be radiographed and the next. This invention is particularly useful for medical applications, and in the medical field, particularly important in mammography.