Abstract: The present invention relates to automatic exposure control implemented in imaging by electromagnetic radiation, in particular to automatic exposure control in film-based mammography, which is based on a completely new approach as compared with the solutions currently in use, which utilize adjustment curves and/or tables constructed on the basis of empiric tests. The new approach includes modeling into the AEC system the radiation spectra obtainable from the radiation source as a function of its operating parameters and attenuation of the spectrum as the radiation traverses components of the imaging apparatus. By measuring the thickness of the object to be imaged and knowing the initial spectrum and its calculable behavior, a correspondence between the AEC signal and the desired darkening of the image can be achieved which is based on true density of the object being imaged.

Abstract: A method of calculating an exposure a patient receives during radiography includes retrieving a value of a dose rate, which is associated with a value of the tube voltage of an X-ray tube, from a first lookup table that is created in advance, retrieving a value of an area of an X-ray field, which is associated with a value indicating the positions of blades included in a collimator that limits a range of X-ray radiation, from a second lookup table that is created in advance, and calculating the product of the dose rate, the area of the X-ray field, the tube current of said X-ray tube, and an X-irradiation time.

Abstract: The invention relates to a method to measure the entrance dose of a radiology apparatus of the type comprising an X-ray beam source, and a detector for the X-ray beam after it has passed an object of interest carried on a table placed between the source and the detector, wherein the X-ray beam source is placed above said table and wherein the distance between the X-ray beam source and the object is estimated taking into account the object's morphology, for determining said entrance dose. An attenuation-ratio is calculated depending on energy-levels of the X-ray beam leaving the X-ray beam source and arriving at the detector respectively, and that the object's thickness is calculated depending on said attenuation-ratio, said thickness together with the table-position defining said distance between the X-ray beam source and the object.

Abstract: The area of an irradiation region, and at least one of the area of an object region and the area of a non-object region in a radiation image obtained by radiographing an object are calculated. The effective dose of radiation from a radiation generator is acquired. An area exposure dose, the X-ray amount radiated on the object, is calculated on the basis of the area of the irradiation region, one of the area of the object region and the area of the non-object region, and an effective dose.

Abstract: The area of an irradiation region, and at least one of the area of an object region and the area of a non-object region in a radiation image obtained by radiographing an object are calculated. The effective dose of radiation from a radiation generator is acquired. An area exposure dose, the X-ray amount radiated on the object, is calculated on the basis of the area of the irradiation region, one of the area of the object region and the area of the non-object region, and an effective dose.

Abstract: The object of the present invention is to enable photographing of a desired X-ray image in accordance with each of fluoroscopy, radiography of moving images in an area of interest and spot radiography by simplified operations, and to reduce an exposure dose to a subject. A correlation table is previously input before radiographing (S1), and is memorized (S2). A radiographer sets an irradiation field R to R1 (S3), and an X-ray aperture is opened by predetermined quantity (S4). An opening value is sent to a control part (S5), and X-rays irradiate a subject P on an irradiation condition of a tube voltage (V) and tube current (A) based on the correlation table (S6). The emitted X-rays pass through the subject, enter a planar X-ray-detecting element, then are read and converted to picture signals.

Abstract: In an x-ray apparatus and method to determine the radiation dose in x-ray examinations, the x-ray apparatus has an x-ray radiator, an automatic exposure timer, and a laser range finder to detect the focus-patient separation between the x-ray radiator and a patient, and a computer device determines the necessary radiation dose using the thickness of the body part of the patient to be examined. The thickness is calculated from the acquired focus-patient distance and geometric data of the x-ray apparatus.

Abstract: According to a radiation imaging apparatus, any separate AEC sensor need not be prepared. Additionally, the apparatus main body can be made compact. To accomplish this, the radiation imaging apparatus has a first optical conversion element that converts incident radiation into an electrical signal, and generates image information on the basis of the electrical signal output from the first optical conversion element. Below a portion that is aligned to the gap between the first optical conversion elements, a plurality of second optical conversion elements which detect the incident amount of the radiation from the gap are formed. Exposure control for the radiation or control of the optical conversion elements is executed on the basis of the detection result by the second optical conversion element.

Abstract: An apparatus for recording a 2D image of an object comprises a plurality of 1D detector units, each exposed to ionizing radiation, as transmitted through or scattered off the object, and being arranged for 1D imaging of the radiation, to which it is exposed. The detector units are distributed in an array such that the 1D images of the radiation from the detector units are distributed over a substantial portion of the 2D image. The apparatus includes a device for moving the detector units relative the object while the detector units repeatedly detect to create the 2D image of the object; and a control device for controlling the detector units to detect ionizing radiation during a short period of time before or during an initial part of the movement; calculating an optimum exposure time for the repeated detection based on the short period of time detection; and controlling the repeated detection to automatically obtain the optimum exposure time.

Abstract: A computed tomography (CT) device has adjustable operational parameters and a control unit and a unit for preselecting a combination of operational parameters for an examination to be carried out. The control unit determines, for the case where a combination of operational parameters which might lead to an impermissible operating state is preselected for an examination to be carried out, a value for at least one operational parameter which deviates from the preselected combination of operational parameters and for which the planned examination can be carried out in a manner avoiding the impermissible operating state without a significant reduction in the image quality by comparison with the preselected combination of operational parameters.

Abstract: When a phototimer unit is used for exposure control, a deterioration in a S/N ratio occurs, and optimal exposure cannot be performed due to a deviation from a proper image sensing position and the like. Therefore, there is provided a radiation image sensing apparatus comprising an X-ray image sensing panel which is capable of non-destructive reading and adapted to sense an object image by allowing radiation from an X-ray source to pass through an object, and a control circuit adapted to perform control to stop emission of radiation from the X-ray source on the basis of a signal obtained from the X-ray image sensing panel by non-destructive reading in the image sensing operation.

Abstract: A method for creating a volumetric data set representing a three-dimensional distribution, such as a dose distribution produced by a radiosurgery system uses a plurality of stacked sensors (12) to obtain two-dimensional cross sectional images of the distribution. The images are optically scanned in a scanner (20) to obtain digitized two-dimensional images which can be processed by software in a computer (22). Each of the sensors (12), which may be, for example, a sheet of X-ray sensitive film, is marked with a visible fiducial mark (17). The software locates images of the fiducial marks (17) in the digitized images. The locations of the fiducial marks (17) indicate the proper orientation and sequence of each image. The software populates a volumetric data structure with data from the scanned images. Interpolation may be used to increase the resolution of the data structure.

Abstract: A radiation image recording medium is exposed to radiation passing through an object to record a radiation image of the object carried by the radiation. A heavy-element-containing phosphor sheet which is formed by heavy-element-containing phosphors containing therein a heavy element to emit light in an amount corresponding to the dose of radiation irradiated thereto is opposed to the radiation image recording medium on the side opposite to the object. A detector detects light emitted from the heavy-element-containing phosphor sheet.

Abstract: In a method and apparatus for determining and documenting, from current x-ray image data, x-ray exposure values employed for producing an x-ray exposure or a sequence of x-ray exposures by irradiation of a radiation detector with x-rays form an x-ray diagnostic source, an exposed image region of the radiation detector is determined, and a region of interest within the exposed image region also is determined. An x-ray image exposure value is determined from the grey scale values of the pixels in the region of interest. The x-ray image exposure value is normalized with respect to a signal value. Measurement values employed for producing the exposed image region are independently measured, and, using these measurement values, the normalized value is converted into a physical unit. The physical unit is stored, associated with the measurement values, for documentation.

Abstract: In a radiographic apparatus comprising: a first photoelectric converter which converts incident radiation to an electric signal and acquires image data; and a second photoelectric converter formed on the same substrate as that of the first photoelectric converter, which converts incident radiation to an electric signal, a time constant of the first photoelectric converter is set larger than a time constant of the second photoelectric converter.

Abstract: In an X-ray imaging apparatus, an optical sensor (phototimer detection unit) corresponding to a conventional photomultiplier is incorporated in a two-dimensional sensor (on a signal line), and a signal from the phototimer detection unit is integrated and monitored, thereby performing exposure control. This makes it possible to incorporate the phototimer detection unit without affecting the aperture ratio of pixels which influence the performance of the X-ray imaging apparatus and the characteristics of a MIS type photoelectric conversion unit, thereby performing proper exposure control.

Abstract: An x-ray detector apparatus comprises an array of detector pixels (20), each pixel (20) comprising a conversion element (26, 260) for converting incident radiation into a charge flow, a charge storage element (28) and a switching device (29) enabling the charge stored to be provided to an output of the pixel (20). A plurality of dose sensing pixels further comprise a dose sensing element (40, 50) during x-ray exposure results in a change in the charge stored on the charge storage element (28) and also results in a dose sensing signal being generated which can be read out from the pixel (20). The dose sensing pixels enable a dose signal to be obtained without reading the charges stored on the pixel charge storage elements, so that dose sensing can be carried out during exposure.

Abstract: The invention relates to a method for exposure control which is intended notably for dynamic X-ray examinations of an object involving a varying X-ray absorption as well as to an X-ray generator which includes an automatic exposure control unit for carrying out such a method. The method and the device are characterized notably in that an exposure kV start voltage and a maximum exposure time Tmax (for example, 100 ms) can be defined; in order to avoid motional unsharpness in the image, these variables may not be exceeded.

Abstract: This invention discloses a radiation imaging apparatus. According to the radiation imaging apparatus of this invention, any separate AEC sensor need not be prepared. If an AEC sensor is arranged on the radiation imaging apparatus, as in the prior art, the image quality degrades because an image sensor receives radiation that is attenuated by the AEC sensor. This can be avoided in this invention. Additionally, the apparatus main body can be made compact. To accomplish this, the radiation imaging apparatus has a first optical conversion element that converts incident radiation into an electrical signal, and generates image information on the basis of the electrical signal output from the first optical conversion element. Below a portion that is aligned to the gap between the first optical conversion elements, a plurality of second optical conversion elements which detect the incident amount of the radiation from the gap are formed.

Abstract: An X-ray imaging apparatus including an X-ray generation means for emitting X-rays, and an X-ray detector on which a grid selected from a plurality of different types of grids is removably mountable. The X-ray detector receives the X-rays emitted from the X-ray generation means, and obtains an X-ray image. The X-ray detector includes an automatic exposure control (AEC) detector for detecting the quantity of X-rays emitted from the X-ray generation means and for outputting a signal based on the detected quantity. The X-ray imaging apparatus also includes a control means for controlling the X-ray generation means and the AEC detector, where the control means controls the X-ray generation means based on the signal output from the AEC detector, and where the control means controls the AEC detector using correction data to correct an exposure detection element forming a part of the AEC detector.

Abstract: A radiation detector has a plurality of charge conversion elements which are laid out in a matrix and convert incoming radiation into charges, a plurality of capacitors for storing the charges generated by the charge conversion elements, and charge read elements for reading the charges stored in the capacitors. Signals other than signals originated to charges stored in the capacitors, which are produced upon, e.g., turning on/off the charge read elements are canceled by adjustment means, thus improving the S/N ratio.

Abstract: A radiation therapy device (2) includes a programmable power source (300) and controller (302) that monitor an injected current level and controls heater voltage in response thereto. The heater voltage is reduced in predetermined increments without affecting the beam profile.

Abstract: Method and system aspects for achieving more accurate radiation delivery during radiation treatment by a radiation-emitting system are described. In a method aspect, and system for achieving same, the method includes providing a table of dose rate values for accumulated dosages in a treatment unit of the radiation emitting system, and controlling a dose rate of radiation emitted from the radiation emitting system through utilization of the table of dose rates. Controlling further includes determining an accumulated dosage at a sampling point, and comparing the accumulated dosage to a total desired dosage. The dose rate is adjusted based on the table of dose rate values and the determined accumulated dosage, with the dose rate ramped down as the accumulated dosage nears the total desired dosage. Accumulated dosages include fractional numbers of monitor units.

Abstract: The invention relates to methods for determining an X-ray dose, to which a living organism is exposed because of examination with the aid of an X-ray machine, from a data record that is assigned to an X-ray image produced during the examination. The data record comprises image data assigned to the X-ray image and data suitable for determining the X-ray dose.

Abstract: In a method for modulating a radiation dose from an x-ray tube, and in an x-ray tube-containing apparatus, the x-ray tube has at least one variable operating parameter which, when varied, modulates the radiation dose, with a modulation speed, for x-rays produced by the x-ray tube, and the x-ray tube is operated while varying this parameter through a parameter range to generate modulation speed data, representing modulation speeds of the x-ray tube respectively for different values of the operating parameter. When an examination subject is to be irradiated with an x-ray dose from the x-ray tube, an exposure effect associated with the exposure of the subject to the radiation dose is identified, this exposure effect being dependent on modulation of the radiation dose.

Abstract: An electronic exposure dose meter and a radiation handling operation management system is capable of realizing real time exposure management. The radiation handling operation management system has monitoring unit receiving an exposure dose amount measured by an electronic exposure dose meter having a radiation detector, its counter circuit and a PHS transmission and reception antenna, from a plurality of transmission and reception base station installed in a radiation handling operation site through bidirectional communication with a central management section via an external management base station, and deriving position of user of the electronic exposure dose meter for collecting and displaying position and exposure dose amount of the user. The electronic exposure dose meter has a radiation detector, a counter circuit, a PHS antenna for bidirectional communication with a central management section.

Abstract: This invention is to provide a system which has a plurality of sensor units and can efficiently sense an image. A sensing system includes a plurality of sensor units, a plurality of selection switches that are arranged in correspondence with the plurality of sensor units, respectively, and select corresponding sensor units, and a control circuit for setting a sensor unit selected by the selection switch in a ready state and an unselected sensor unit in a sleep state.

Abstract: An automatic exposure control for an x-ray system using a large area solid state x-ray detector (26) includes an exposure control (36, 34) arranged to generate data of interest within the data generated by the detector and to adjust the dosage of x-rays to a predetermined level in response to data of interest so that an x-ray image of a patient is generated using the predetermined level.

Abstract: The invention relates to a method for operating a radiation examination apparatus, especially an X-ray apparatus, that includes a radiation source and a detector device. The invention proposes the use of a control signal for “during pulse” radiation control, being a combination of a dose or a dose rate signal, measured by a dose rate measuring device, and an adaptive control value that is obtained, using an adaptive control algorithm, from the mean image working points within a selected region of interest of every individual preceding image within an image sequence. A detector device and a radiation examination apparatus are also claimed.

Abstract: When a phototimer unit is used for exposure control, a deterioration in a S/N ratio occurs, and optimal exposure cannot be performed due to a deviation from a proper image sensing position and the like. Therefore, there is provided a radiation image sensing apparatus comprising an X-ray image sensing panel which is capable of non-destructive reading and adapted to sense an object image by allowing radiation from an X-ray source to pass through an object, and a control circuit adapted to perform control to stop emission of radiation from the X-ray source on the basis of a signal obtained from the X-ray image sensing panel by non-destructive reading in the image sensing operation.

Abstract: A method of and a device for forming an image of an irradiated object in which images are formed with different exposure levels and the differently exposed images are combined so as to form a single image. The device includes a source and an imaging device which is connected to the source in order to form the image, the imaging device being arranged to form images with different exposure levels and being provided with an image processor in which the differently exposed images are combined so as to form the single image. The device produces images of a quality which is comparable to that of images acquired by means of a device having a much larger dynamic range.

Abstract: One embodiment of the present invention is a method for measuring a radiation dose of a patient applied by a computerized tomography (CT) imaging system having a radiation source emitting a radiation beam and a radiation detector. The method includes steps of: scanning a patient with the radiation beam; imaging the patient utilizing radiation detected by the radiation detector; and estimating a patient radiation dose from said imaging utilizing a measurement of radiation delivered to only a portion of the detector during said imaging. The present invention permits the advantages of a post-patient collimated detector array to be realized while providing an accurate estimate of patient radiation dosage.

Abstract: X-ray diagnostic installation has a high-voltage generator for an X-ray tube for generating an X-ray beam, an X-ray image converter that has a scintillator layer and a semiconductor layer with light-sensitive pixel elements arranged in a matrix, and a combined back light/dose measuring unit arranged therebehind in the beam direction that is formed by an array of light-emitting diodes arranged in a matrix, as backside illumination, and light-sensitive sensors that acquire the X-ray dose, as sensors, and a measurement transducer for the control of the high-voltage generator connected thereto. Light waveguides are arranged in front of the light-sensitive sensors and between the light-emitting diodes, these light waveguides conducting the light that proceeds from the X-ray image converter during the irradiation and that is incident onto the combined back light/dose measuring unit onto the light-sensitive sensors.

Abstract: The invention relates to an X-ray diagnostic device in which the dose applied to a patient is determined and in which the effective dose which is of relevance for the radiation load is calculated from this dose as well as from a weighting factor which is fetched in dependence on the relevant anatomical region to be examined.

Abstract: Method and system aspects for achieving more accurate radiation delivery during radiation treatment by a radiation-emitting system are described. In a method aspect, and system for achieving same, the method includes providing a table of dose rate values for accumulated dosages in a treatment unit of the radiation emitting system, and controlling a dose rate of radiation emitted from the radiation emitting system through utilization of the table of dose rates. Controlling further includes determining an accumulated dosage at a sampling point, and comparing the accumulated dosage to a total desired dosage. The dose rate is adjusted based on the table of dose rate values and the determined accumulated dosage, with the dose rate ramped down as the accumulated dosage nears the total desired dosage. Accumulated dosages include fractional numbers of monitor units.

Abstract: Method and system aspects for achieving more accurate radiation delivery during radiation treatment by a radiation-emitting system are described. In a method aspect, and system for achieving same, the method includes providing a table of dose rate values for accumulated dosages in a treatment unit of the radiation emitting system, and controlling a dose rate of radiation emitted from the radiation emitting system through utilization of the table of dose rates. Controlling further includes determining an accumulated dosage at a sampling point, and comparing the accumulated dosage to a total desired dosage. The dose rate is adjusted based on the table of dose rate values and the determined accumulated dosage, with the dose rate ramped down as the accumulated dosage nears the total desired dosage. Accumulated dosages include fractional numbers of monitor units.

Abstract: The invention relates to an ionization chamber which includes a plurality of measuring field electrodes (131 . . . 133) which are arranged on a substrate (120) at a distance from one another and are provided with supply leads (134), and at least one electrode (180) which is arranged at a distance from and faces the substrate and emits charge carriers under the influence of X-rays. An insulating layer (140; 190) provided on the supply leads and/or on the electrode, at least at the area of the supply leads, prevents the signals from the ionization chamber from being falsified by the charge carriers incident on the supply leads. The electrically insulating (layers) have such a high X-ray transparency that they are practically not reproduced in an X-ray image.

Abstract: An X-ray diagnostic apparatus forms image data using an arbitrary region in the detectable area of a planar detector having a plurality of X-ray detector elements arrayed in a matrix. An X-ray sensor array for exposure-controlling having a plurality of X-ray sensors arrayed in a matrix overlaps the planar detector. An X-ray controller controls an X-ray tube unit on the basis of an output from the X-ray sensor array in order to optimize the X-ray dose on a subject. A controller selects at least one X-ray sensor in accordance with the position of a partial region where an image is formed. The controller controls at least one of the X-ray sensor array and X-ray controller so as to control the X-ray dose on the basis of an output from the selected X-ray sensor.

Abstract: Disclosed herein is a radiographic imaging system which performs system performance monitoring by (1) using automatic exposure control (AEC) components to predict the average image gray level; (2) obtaining measured average image gray levels from the portions of the X-ray detector situated in the X-ray shadow of the AEC components; and then (3) comparing the predicted and measured values. The predicted values are determined by use of a prediction model which is modified by a learning system over successive exposures to provide more accurate predictions. After the learning system has sufficiently developed the prediction model, the error between the predicted and measured gray level values may be monitored in later exposures and an error routine can be activated if the error exceeds a predetermined threshold. In this case, the error may indicate that system components in the imaging chain (e.g., the detector or AEC components) require maintenance.

Abstract: A digital automatic X-ray exposure control system (22, 24, 26) includes a digital frequency modulated output signal circuit (40) generating a digital frequency modulated output signal (42) having a pulse rate that is frequency modulated in proportion to the level of an X-ray beam received at an ion chamber of an X-ray imaging apparatus. A digital input circuit (22) connected to the output circuit via a digital communication interface cable (26) receives the digital output signal and generates an exposure termination signal (80) for use by the X-ray imaging apparatus to interrupt the generation of the X-ray beam at a precise exposure level. The digital input circuit includes a digital counter circuit (70) for counting pulses in the output signal as a pulse count value that is compared against an exposure length parameter value (74) for generating a count match signal (76) based on a correspondence therebetween.

Abstract: An X-ray examination apparatus according to the present invention includes an X-ray detector for deriving an image signal from an X-ray image, and an exposure control system for adjustment of the X-ray examination apparatus on the basis of a relevant part of the X-ray image. The exposure control system is arranged to group pixels of the X-ray image in one or more clusters on the basis of their brightness values and to select the relevant part of the X-ray image from the clusters.

Abstract: An X-ray diagnosis machine having an X-ray source (3) and a recording device with a photo-timer which has at least one measurement field (2) in a radiation detector plane (1) essentially parallel to the image plane. The measurement field is mounted so as to be capable of being displaced in the radiation detector plane.

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 produce 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 supplying 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 apparatus acquires an X-ray image of an object by radiating X-rays to the object and includes an X-ray radiator for radiating X-rays to an object. An imager acquires an X-ray image of the object and radiation dose controller controls the radiation dose so as to acquire an X-ray image having a predetermined X-ray relative noise level on the basis of an image level of a predetermined area in the X-ray image.

Abstract: To make it possible to decrease an X-ray exposure on an operator and to obtain an image of high quality upon fluoroscopy operation an X-ray tube is rotated to acquire data, an X-ray radiation dose is set to "0" in a predetermined angular range including an angle at which the alignment of the X-ray tube with the operator's hand is brought about, and the X-ray radiation dose is set to an ordinary one at an angle in a range other than that angular range. The predetermined angular range is established using a light beam which enables to see what part of the field has no X-ray radiation exposure, thereby increasing his safety.

Abstract: The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

Abstract: Automatic exposure control for an x-ray system using a large area solid state x-ray detector includes an array of photodiodes located behind the x-ray image detector to measure photons passing therethrough. The resulting currents from selective ones of these photodiodes are combined to provide a signal used to control the x-ray exposure.

Abstract: An x-ray imaging system includes a source of x-rays, a video camera which produces an image signal formed by x-ray attenuation values, and image signal processor and a video monitor for displaying the x-ray image. The system also has an automatic image control that includes a peak detector, an average brightness detector and a transfer function generator for the image processor. The peak detector receives the image signal and produces a video gain control signal for controlling the video camera in response to a comparison of a peak level of the image signal to a peak reference level. The average the brightness detector employs the image signal to produce a feedback signal which controls by the source of x-rays. The transfer function generator produces a histogram of intensity levels in the image signal which histogram forms a look-up table that is used by the image processor to transform the image signal into the adjusted image signal for display.

Abstract: An x-ray diagnostic installation has a high-voltage generator, an x-ray tube supplied by the high-voltage generator, and a solid-state image converter on which x-rays, attenuated by an examination subject disposed between the x-ray tube and the solid-state image converter, are incident. A control unit is connected to the high-voltage generator and to the solid-state image converter, and controls the high-voltage generator to cause the x-ray tube to emit a first x-ray pulse of a short duration which produces an x-ray exposure in the solid-state image converter. The control unit conducts a read out of the solid-state image converter to obtain a measured value representative of the x-ray dose rate, the control unit using this measured value to calculate the x-ray transparency of the examination subject and, from the x-ray transparency, to calculate an optimum x-ray dose.

Abstract: A medical radiological diagnostics system having an automatic exposure unit employs signal acquisition and a processing circuitry for controlling the radiation source so as to obtain easily diagnosed exposures with a low radiation load. This is accomplished by disposing a stray radiation grid between the radiation receiver and a radiation sensor, or by selecting the spacing between the radiation receiver and the radiation sensor such that scattered radiation is not incident on the radiation sensor, or, in a system having an x-ray image intensifier and a light sensor, by supplying the output signal of the light sensor to the control circuit through a high-pass filter. In all versions, the measured signal is not disadvantageously influenced by scattered radiation, so that a correct exposure of x-ray film is possible.