Abstract: A method for obtaining data includes scanning an organ with an imaging system emitting X-rays and modulating the emitted X-rays with an organ specific bowtie addition.

Abstract: A switching mechanism is configured such that a lower limb radiographic filter 11a is moved inside a radiation field of the X-rays that is an opening portion of an X-ray movable restriction only when radiographing a region of a subject from the groin to the toe, or the filter is moved outside the radiation field when radiographing the lumber region of the subject. With this switching mechanism thus constituted, it is possible to lighten a burden of the operator, and realize the X-ray radiographic apparatus having high universality.

Abstract: A device for filtering a ray bundle of electromagnetic radiation, particularly an X-ray bundle has different filter stages, produced by multiple filters that can be adjusted into the ray bundle, a drive for moving the filters, and separate arms for moving each of the filters. The respective first ends of the arms engage at the appertaining filter and the respective other ends thereof are chargeable with a force generated by the drive. Dependent on the motion of the drive, each of the filters can either be set into the beam path by charging the appertaining arm with an actuating force or can be retrieved from the ray bundle by charging the arm with a restoring force. A dog driven by the drive is able to be brought into contact with two detents respectively present at each of the arms. An IN detent is provided for charging the arm with the actuating force and an OUT detent is provided for charging the arm with the restoring force.

Abstract: An X-ray apparatus has a radiation source, an interchangeable radiation filter and an area dose measuring device having a measurement chamber with an allocated evaluation device for determining the area dose product on the basis of a measured signal provided by the measurement chamber. The measurement chamber is arranged preceding the filter in the beam path with reference to the radiation propagation direction. A detector recognizes the nature and/or the type of radiation filter that is currently inserted in the beam path. The evaluation device corrects the area dose product that is calculated from the measured signal from the measurement chamber on the basis of at least one filter-specific correction value that is selected as a result of the detection of the filter nature and/or type.

Abstract: An apparatus for filtering an x-ray beam emitted by an x-ray source comprises a filter, adjustable from a parked position (P) outside of a path of the x-ray beam into a filtering position (F) in the x-ray beam path. A corresponding first sensor device detects when the filter in the filtering position (F), and a corresponding second sensor device detects when the filter in the parked position (P). Further, sensor signals are communicated by the first and second corresponding sensors to an evaluation device. The evaluation device generates a report if the filter is not in at least one of the parked position (P) and the filtering position (F).

Abstract: There is disclosed an X-ray analyzer capable of precisely measuring a trace amount of cadmium contained in plastic. The analyzer has an X-ray filter assembly between an X-ray tube having an Rh target and a plastic sample. The filter assembly consists of first, second, and third X-ray filters which are made of zirconium, copper, and molybdenum, respectively. The first through third X-ray filters have thicknesses of about 100 &mgr;m, 200 &mgr;m, and 40 &mgr;m, respectively.

Abstract: A system for creating an image of the internal features of an object includes an X-ray source and detector array positioned to interpose the object between the X-ray source and the detector array. An X-ray beam is passed through the object along a first path. While passing through the object, the beam is successively filtered twice, each time with a different filter. The successive filtration of the beam results in the production of two electrical signals by the detector which are processed to create an image signal for the path. The process is repeated for a plurality of paths through the object and the resulting image signals are combined using traditional computer tomography techniques to produce a composite image of the object.

Abstract: In order to obtain an X-ray tomographic image with high quality while minimizing the exposed dose to a subject by employing the most suitable filter according to the region of the subject to be scanned, a filter unit 6 having filters 6a-6c having different transmission properties are provided below an X-ray tube 4 in a gantry apparatus. To obtain an X-ray tomographic image, upon determining the scan region of the subject, a motor 7 is driven to position one of the filters corresponding to the scan region just below the X-ray tube 4 for employing the filter, and X-rays are applied to the subject through the filter.

Abstract: A system for creating an image of the internal features of an object includes an X-ray source and detector array positioned to interpose the object between the X-ray source and the detector array. An X-ray beam is passed through the object along a first path. While passing through the object, the beam is successively filtered four times, each time with a different filter. The successive filtration of the beam results in the production of four electrical signals by the detector which are processed to create an image signal for the path. The process is repeated for a plurality of paths through the object and the resulting image signals are combined using traditional computer tomography techniques to produce an image of the object.

Abstract: A system for creating an image of the internal features of an object includes an X-ray source and detector array positioned to interpose the object between the X-ray source and the detector array. An X-ray beam is passed through the object along a first path. While passing through the object, the beam is successively filtered four times, each time with a different filter. The successive filtration of the beam results in the production of four electrical signals by the detector which are processed to create an image signal for the path. The process is repeated for a plurality of paths through the object and the resulting image signals are combined using traditional computer tomography techniques to produce an image of the object.

Abstract: An X-ray apparatus with an X-ray source for producing a beam of X-rays, an X-ray detector for detecting the beam, and an X-ray filter with filter elements. The X-ray filter is arranged between the X-ray source and the X-ray detector to attenuate the X-ray beam in each independent filter element individually. Each filter element can receive a liquid which is electrically conductive and X-ray absorbing, and is supplied via a transport channel, the X-ray absorptivity of each filter element being discretely adjustable by step-wise adjustment of the level of the liquid in each filter element. Each filter element includes a first electrode which is located in the wall of the filter element, on top of a substrate layer for applying an electric potential to the wall of the filter element. A second electric potential is applied to the liquid via a second electrode.

Abstract: An X-ray apparatus with an X-ray source for producing a beam of X-rays, an X-ray detector for detecting the beam, and an X-ray filter with filter elements which is arranged between the X-ray source and the X-ray detector so as to attenuate the X-ray beam in each independent filter element individually. Each filter element can receive a liquid having electrically conducting properties and X-ray absorbing properties, the value of the X-ray absorption of the filter element being dependent on the level of the X-ray absorbing liquid in the filter element. Each filter element includes a first electrode (23) which is located in the wall of the filter element and on top of the substrate layer (38) in order to apply an electric potential to the wall of the filter element. A second electric potential is applied to the liquid via a second electrode.

Abstract: A beam filtering device comprises a strip carrying at least one filter. The strip is wound onto drums between which the strip extends. A rotary drive mechanism drives the drums in rotation to cause the strip to advance and wind onto one drum while unwinding from the other. Advancing the strip makes it possible to arrange one of the filters on the strip in the space between the drums. This allows radiation filtering characteristics to be readily and rapidly modified.

Abstract: A method and system for on-line measurements of mineral additives in or on a paper web utilizing shaped spectrum x-rays and solid-state PIN detectors. Each of three detectors are cover by a filter used to shape the spectrums of x-rays received by the detectors. The filters are selected to maximize sensitivity differences between detectors for the desired detectable mineral additives. A computer processes signals from the detectors and from basis weight and moisture measuring instruments to determine total mineral content, and the individual amounts of mineral additives in or on (e.g. coating) the paper web.

Abstract: An X-ray filter comprises an array of filter elements (5) an control circuit, the control circuit comprising an array of switching devices (33) provided on a common substrate (52), a switching device (33) being provided for each filter element for switching a control signal to the respective filter element. An output terminal of each switching device is provided with an external connection portion (54) located at the respective switching device. An array of external connection portions (54) is thus provided over the array of switching devices (33). The connection portions are then bonded to a connection block of the array of filter elements. This avoids the need to use edge connections of the substrate (52), and provides a secure mechanical and electrical connection between the control circuit and the filter array.

Abstract: In order to obtain an X-ray tomographic image with high quality while minimizing the exposed dose to a subject by employing the most suitable filter according to the region of the subject to be scanned, a filter unit 6 having filters 6a-6c having different transmission properties are provided below an X-ray tube 4 in a gantry apparatus. To obtain an X-ray tomographic image, upon determining the scan region of the subject, a motor 7 is driven to position one of the filters corresponding to the scan region just below the X-ray tube 4 for employing the filter, and X-rays are applied to the subject through the filter.

Abstract: An X-ray apparatus with an X-ray source for producing a beam of X-rays, an X-ray detector for detecting the beam, and an X-ray filter with filter elements which is arranged between the X-ray source and the X-ray detector so as to attenuate the X-ray beam in each independent filter element individually. Each filter element can receive a liquid having electrically conducting properties and X-ray absorbing properties, the value of the X-ray absorption of the filter element being dependent on the level of the X-ray absorbing liquid in the filter element. Each filter element includes a first electrode (23) which is located in the wall of the filter element and on top of the substrate layer (38) in order to apply an electric potential to the wall of the filter element. A second electric potential is applied to the liquid via a second electrode.

Abstract: Methods and apparatus for dose reduction in a computed tomography (CT) system are described. In one embodiment, the CT system includes a pre-patient collimator and a configurable multislice detector array. The pre-patient collimator includes a plurality of eccentric cams and a filtration device for altering the x-ray beam radiated from a x-ray source. The eccentric cams are positioned to collimate the x-ray beam and may be independently positioned to provide z-axis correction of the x-ray beam. The filtration device includes a plurality of filters for altering the x-ray beam. In operation, an operator selects the type of test and the quantity and thickness of the slices. After altering the detector and collimator configuration, slice data for each slice is gathered.

Abstract: An X-ray device with an X-ray source to produce a beam of X-ray radiation, an X-ray detector to detect this radiation and an X-ray filter with filter elements which is positioned between the X-ray source and the X-ray detector to attenuate the X-ray beam in each independent filter element individually. Every filter element (213) can contain a fluid (32) which is electrically conducting and X-ray absorbing, which is supplied via a transport channel (30), whereas the value of the X-ray absorption of each filter element can de discretely adjusted by a stepwise adjustment of the level of the fluid (32) within each filter element.

Abstract: The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an irregular hydrostatic pressure distribution in the X-ray filter. In order to reduce the effects of the gravitational forces on the transport of the X-ray absorbing liquid, the duct connecting the filter elements to the reservoir is subdivided into sub-ducts and the reservoir is subdivided into chambers, each chamber being connected to at least one sub-duct. The X-ray apparatus also includes means for keeping the sub-ducts aligned with a horizontal plane.

Abstract: The X-ray examination apparatus includes an X-ray source, an X-ray detector and an X-ray filter which is located between the X-ray source and the X-ray detector. The X-ray filter includes elements, notably capillary tubes, and the X-ray absorptivity of separate filter elements is adjustable by adjustment of a quantity of X-ray absorbing liquid in the respective filter elements. The quantity of X-ray absorbing liquid in the individual filter elements is adjusted by way of electric voltages applied to the individual filter elements. A control system is provided to apply the electric voltages selectively to the individual filter elements. The control system includes voltage lines and switching elements which electrically couple the filter elements to an electric voltage source. The filter elements are formed by spaces between corrugated plates or parallel plates provided with separating members, such as protrusions which extend transversely of the plates. The voltage lines are disposed on the plates.

Abstract: An X-ray examination apparatus (1), including an X-ray source (2) and an X-ray detector (5), is provided with an X-ray filter (6) which is arranged between the X-ray source and the X-ray detector. The X-ray filter (6) includes a plurality of filter elements (7) whose X-ray absorptivity can be adjusted by adjustment of a quantity of X-ray absorbing liquid (14) within the individual filter elements; a first end of individual filter elements communicates with the X-ray absorbing liquid whereas a second end communicates with an X-ray transparent liquid (12). The X-ray filter is preferably provided with a pressure control system for independent control of the liquid pressure in individual row ducts (11) and individual column ducts (13). Individual filter elements are preferably provided with a piston for separating the X-ray absorbing liquid from the X-ray transparent liquid.

Abstract: Methods and apparatus for dose reduction in a computed tomography (CT) system are described. In one embodiment, the CT system includes a pre-patient collimator and a configurable multislice detector array. The pre-patient collimator includes a plurality of eccentric cams and a filtration device for altering the x-ray beam radiated from a x-ray source. The eccentric cams are positioned to collimate the x-ray beam and may be independently positioned to provide z-axis correction of the x-ray beam. The filtration device includes a plurality of filters for altering the x-ray beam. In operation, an operator selects the type of test and the quantity and thickness of the slices. After altering the detector and collimator configuration, slice data for each slice is gathered.

Abstract: An apparatus for properly centering and/or collimating an X-ray beam with respect to a target to be radiographically imaged. A field definer is situated between an X-ray source and an X-ray detector at the location where the target is to be situated. The field definer includes a pair of stops between which the target may be located, and the stops may be horizontally relocated relative to each other to be placed in abutment with the target. A sensor in communication with the stops produces a signal dependent on the distance between the stops, and a controller utilizes this signal to adjust the X-ray source to emit radiation in a desired area with respect to the field between the stops. As an example, a target may be situated between the stops, the stops may be adjusted in abutment with the target, and the X-ray source will then be collimated to emit a radiation beam which is incident only on the target between the stops.

Abstract: A filter having compensating plates, each having a first plate element which can be moved translationally with respect to a frame and a second plate element which can be moved relative to the first plate element so that, when the plates are in an active position, the thickness of absorbent material through which the X-ray beam passes is constant.

Abstract: X-ray examination apparatus including a filter An X-ray examination apparatus (1) includes an X-ray source (2), an X-ray detector (5) and an X-ray filter (6). The X-ray filter (6) is arranged between the X-ray source and the X-ray detector. The X-ray filter (6) includes a plurality of filter elements (7) whose X-ray absorptivity can be adjusted by adjusting a quantity of X-ray absorbing liquid (30) present in individual filter elements (7). The filter elements are formed by substantially parallel plates (8), respective plates being provided with separating members (10) which project approximately transversely from the plane of such a plate. The filter elements are formed notably by parallel corrugated plates or by parallel plates provided with partitions extending transversely from the plates.

Abstract: The device is used for compensating a hyper transparency area due to air inside or outside an organ while using a gantry mounting radiography apparatus with digital subtraction (DSA). The device comprises compensating filters and a supporting assembly for connecting the filters in front of the X-ray source. Each filter extends in a filter plane while the organ defines a median plane in which the rotation axis of the arms of the apparatus is substantially lying. The supporting assembly is designed to keep the filter in front of the X-ray source and in registry with the X-ray source and the hyper transparency area while keeping the filter plane parallel to the reference plane during rotation of the arms. Unlike existing X-ray compensating devices which are stationary, the present invention automatically sets itself for radiography of different views in function of the rotation of the arms of the apparatus.

Abstract: A novel scatter filter for use in positron emission tomography which filters out deflected rays of energy due to Compton scattering which generally have a lower energy. The filter allows most of the undeflected rays to pass through by providing a layer of material having a particular density and atomic number between the detector and the source. Multiple layers of filters may also be provided to filter out characteristic x-rays from the first layer of filter.

Abstract: A method of establishing coincidence between a field size of a light field used in a setup mode of a radiation system and a field size of a radiation field used in an operation mode of the system includes providing automatic adjustment of field-defining structure to compensate for differences in optical properties of the light and the radiation. A light beam passing through the field-defining structure typically exhibits greater scattering than an X-ray beam passing through the structure. For each of a number of different settings of the field-defining structure, the difference between the field sizes of the light and the radiation are determined and recorded. Then, for a particular desired field size, the field-defining structure can be automatically adjusted to provide compensation.

Abstract: An X-ray diagnostic apparatus has a device for controlling an X-ray source with regard to the emission of an X-ray beam and a filter positioner for the introduction or removal of at least one radiation filter into or out of the beam of radiation. A monitoring device checks whether there exists a positive difference signal between an output of a dosage power regulator and a kV controller. Given the presence of a positive difference, the monitoring device controls the filter positioner with regard to the removal of the radiation filter from the beam of radiation.

Abstract: An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously.

Abstract: A device for manipulating a synchrotron beam bundle is intended to produce properties of the beam bundle, under vacuum conditions, which are adapted to the respective application of deep X-ray lithography, in particular, which are adapted to the scanning regimen. Pairs of diaphragms which are displaceable relative to one another are provided between the object table and an inlet window within a vacuum chamber containing an object table for receiving an object to be irradiated, which object table is adjustable by a scanning movement relative to the synchrotron beam bundle. The pair of diaphragms for which the direction of relative displacement of the diaphragms coincides with the scanning movement is coupled with the scanning movement. Further, a filter chamber is arranged upstream of the vacuum chamber and contains filters which can be inserted into the synchrotron beam bundle.

Abstract: In one embodiment of the invention x-rays pass through an aluminum filter (18) to form filtered x-rays. At least a portion of the filtered x-rays then pass through a portion of a x-ray mask (22) to expose a portion of a photoresist layer overlying a semiconductor substrate. The aluminum filter removes high energy photons from the x-ray spectrum that adversely effect the lithographic patterning process.

Abstract: X-ray apparatus carrying an X-ray tube as a source and an image intensifier as a receptor on opposite ends of a two-limbed C-Arm has a horizontal support arm extending from a base to a vertical support arm for the C-arm. The vertical arm has a plurality of telescoping tubular sections which can be extended or contracted along a vertical axis to raise or lower the C-arm relative to the level of the base. The horizontal arm also extends telescopingly to increase the space between the base and C-arm to give free passage of medical personnel through the space, the base having a height sufficient to hold the horizontal arm above a moderately tall operator. The horizontal arm is pivoted on a vertical axis through the base to swing the C-arm, X-ray tube and image intensifier over a patient table in coordination with extension of the horizontal arm or rotation of the vertical arm sections to scan the X-ray tube and receptor over a large area of the patient table. All movements may be manual or motorized.

Abstract: A filter changer for a radiation transmitter comprises a filter which is adjusted between a first position out of the beam path of the radiation transmitter to a second position in the beam path. The changer includes guides for guiding the filter for movement along a linear path, an arm having one end engaging the filter and the other end engaging an actuating arrangement so that when the arm is rotated against a spring, the filter is moved from the first to the second position and when the arm is released from the actuating arrangement, the spring biases the arm and filter back into the first position.

Abstract: A slit radiography assembly including an X-ray source, and X-ray detector and a slit diaphragm comprised of a plurality of sections juxtaposed in the longitudinal direction of the slit and coacting with controllable attenuation elements wherein: during scanning, a detection assembly includes a plurality of response sections cooperate with the X-ray detector to provide an electric signal representative of the intensity to control the attenuation elements during scanning at initial measuring exposure and subsequent radiographical exposure of the body.

Abstract: A radiographic equalization apparatus comprises a plurality of juxtaposed disks each having a plurality of unique filtration patterns annularly disposed therearound. The disks are rotated relative to one another to obtain a unique attenuation pattern for correcting for overexposures in an x-ray image.

Abstract: An X-ray detector, which is concerned with X-rays having wavelengths of less than 100 .ANG., includes an X-ray filter with a thickness smaller than a previously defined value, a semiconductor light-receiving element arranged behind the X-ray filter, and a measuring device for measuring an output produced by the semiconductor light-receiving element. This detector is provided with a grazing incidence mirror in front of the X-ray filter so that the wavelength selection and intensity measurement can be effected simultaneously. The X-ray detector has important advantages in practical use that the power source system does not come to a large scale, its periphery circuit is simple, and sensitivity is as high as one to two orders than that of a conventional X-ray diode.

Abstract: An X-ray image pick-up method causes X-rays from an X-ray source to be irradiated on an object for picking up its image as passed through a filter capable of restricting any fluctuation of the effective X-ray energy within .+-.10%, and then the X-rays thus penetrated through the object to be picked up by an image pick-up means. Radiation dose with respect to the object and eventually to operators is thereby minimized, while the image pick-up can be realized with a high resolution.

Abstract: A collimator is described for a shielded effective point source of penetrating radiation, e.g. a radiotherapy machine which includes, after a primary collimator 16, a succession of a multileaf collimator 17, and a first and a second pair of independently adjustable block diaphragm leaves 30, 31, and 35, 36 at right angles to each other. By using rectilinear displacement of the multileaf collimator leaves 18 and the block diaphragm leaves 30, 31, a compact arrangement can be provided which fits into a standard RT collimator head. By curving the inner edges of the leaves to be tangential to the boundary ray an optimally reduced penumbra can be achieved. The block diaphragms enable the radiation leakage found in prior multileaf collimators to be minimized for small and off center irradiation patterns.

Abstract: A system for analyzing biological structures by photon absorptiometry is disclosed, including a radiation source emitting photons and at least one source filter which operates to reduce the emission of high energy photons, thereby creating a sharp drop-off at the high end of the detected energy spectrum. The filter radiation is received by a detector which determines the spatial intensity of the radiation over the image area and preferably has a characteristics response which is relatively insensitive to low energy photons, such that the source filter and detector cooperate to measure the intensity of photons within a narrowed band of energy levels.

Abstract: An x-ray diagnostics installation has an x-ray source, an x-ray image intensifier video chain, and a control circuit connected to the output of the video chain which includes a circuit for data reduction which combines a number of image points of the total x-ray image into smaller image regions. A threshold circuit for contour recognition is connected to the output of the reduction circuit, which compares the measured values of the individual image regions to a threshold, and transmits through only those measured signals corresponding to darker regions of the image, and thus corresponding to image regions of relevance.

Abstract: A measuring method employing hard X-rays receives a hard X-ray beam from an X-ray source at first and second sensors substantially simultaneously. The beam directly reaches the first sensor but reaches the second sensor only after penetrating an object to be analyzed and a filter. The ratio of intensity values of the beams detected at the sensors is calculated so that filters producing X-ray absorption coefficients substantially independent of the thickness of objects to be analyzed are identified. Zt, the sum of the products of the atomic numbers Z and thicknesses t of each of the filter members of the identified filters, fall on a straight line graph of Zt versus X-ray tube voltage. Subsequently, filters are quickly selected from the graph during an analysis of objects of similar composition with hard X-rays.

Abstract: Two X-ray transmission images of an object, e.g. an electronic device package structure having plural soldering layers are detected in two directions inclined to the plural layers, on the basis of a relative position relation between both X-ray transmission images, one X-ray transmission image is converted on the assumption that soldering portions to be detected are located at a certain layer, into the image in the direction in which the other X-ray transmission image has been detected, and the converted X-ray transmission image is with the other X-ray transmission image to decide that the soldering portions at coincided positions are located at the layer at issue.

Abstract: A high-speed image recording apparatus comprises a sheet changer for changing a stimulable phosphor sheet at an image recording position, a radiation source drive controller, and a filter changer for changing a radiation filter on a radiation passage between a radiation source and a stimulable phosphor sheet at each image recording step. The sheet changer, the radiation source drive controller and the filter changer are activated by signals sent from a controller to load the stimulable phosphor sheet to the image recording position, to change over the radiation filter, and then to emit radiation to the stimulable phosphor sheet via an object, thereby recording a high energy image and a low energy image of good energy discrimination in stimulable phosphor sheets.

Abstract: A radiation image recording and read-out apparatus comprises a circulation transfer means for transferring a stimulable phosphor sheet along a predetermined circulation path; an image recording section which is disposed in the circulation path and in which a radiation image of an object is recorded on the stimulable phosphor sheet by exposing the stimulable phosphor sheet to radiation passing through the object; an image read-out section which is disposed in the circulation path for scanning the stimulable phosphor sheet with stimulating rays and detecting light emitted from the stimulable phosphor sheet to obtain an image signal; and an erasing section which is disposed in the circulation path and releases residual radiation energy in the stimulable phosphor sheet before the stimulable phosphor sheet is returned to the image recording section. The radiation image recording and read-out apparatus further includes a radiation quality changing filter for changing the quality of the radiation.

Abstract: A radioscopic image former comprises a slit between an X-ray source and a subject to produce an X-ray fan beam to scan the subject. The transmission of the slit is adjusted locally during the scanning depending on local absorptions in the subject. The X-ray fan beam is cyclically modulated. The local modulation frequency depends on the coordinate in the longitudinal direction of the slit. The slit comprises a number of tongues each tongue being excited at or near its resonant frequency. Each tongue has its own frequency or phase and acts as a frequency-selective element.

Abstract: A multioperation accelerator simulating more especially cobalt radiation. According to the invention, an electron accelerator of average energy and a set of targets and filters are provided so as to obtain at least one penetration curve similar to that of cobalt and other closely related curves.

Abstract: A positioning control system controls the shifting of one of a plurality of radiation filters into the ray path. Transducers provide an electric density signal which is dependent upon the density of the examination subject. The control system has an electromotor activated by a control circuit to which the density signal is applied and which activates the motor corresponding to the respective density signal for the purpose of selection of the correct filter. The transducers may be coupled with a device physically acting in compression on a body part of the patient to be examined such that the degree of resistance of the body part to compression is sensed by the transducers as a measure of patient density.

Abstract: An apparatus for slit radiography which comprises an X-ray source and a slit diaphragm through which a body to be examined can be scanned by a planar X-ray fan beam. The slit diaphragm is operatively associated with a plurality of juxtaposed tongue-shaped attenuation elements, which elements are arranged for having their free ends swung to a greater or lesser extent into the X-ray beam so as to effect a local attenuation of the beam. The tongue-shaped attenuation elements form at least one flared configuration as seen from the X-ray source.