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: Grid arrangement (1) for use with an X-ray apparatus (70) that is provided with an X-ray source and a recording element, it being possible, in operation, to place the grid arrangement (1) against the recording element and the grid arrangement being equipped to accommodate a flat grid (3) that comprises a multiplicity of elongated thin lamellae. The lamellae are placed essentially parallel to one another in a direction parallel to one surface of the grid (3), and the lamellae are oriented towards a focal axis a specific distance above the surface of the grid (3). The grid arrangement (1) further comprises drive means (8) which are equipped to move the grid (3) in a pendulum movement essentially about an axis of rotation and adjustment means (4, 10) for adjusting the axis of rotation of the pendulum movement to match the focal axis of the grid (3).

Abstract: The present invention provides an x-ray measuring apparatus for diagnosis having high spatial resolution and high sensitivity, which includes: an x-ray source for emitting x-rays from an x-ray focal spot; an x-ray detector in which a plurality of sensing elements each having a sensitive part and a blind part surrounding the sensitive part are arranged two-dimensionally; data processing means for collecting output signals of the sensing elements and performing data processing; and an anti-scatter grid disposed between the x-ray focal spot and the x-ray detector with predetermined distance from the position of the x-ray focal spot and in which an x-ray transmitting member and an x-ray shielding member are alternately arranged in a first direction.

Abstract: It is an object of one of the inventions to acquire a radiation image in which a stripe pattern originating from a scattered ray removing grid is less apt to interfere with observation. An image acquisition apparatus of one of the inventions includes a sensor for spatially sampling a radiation transmission distribution of an object to be imaged at a spatial sampling interval and acquiring an image of the object, and a scattered ray removing grid for removing scattered rays from the object, wherein an interval of elements of the scattered ray removing grid is set such that a spatial frequency of a stripe pattern, in the image, which originates from the scattered ray removing grid becomes not greater than 40% of a sampling frequency that is a reciprocal of the spatial sampling interval.

Abstract: An X-ray image photographing apparatus includes an image obtaining portion for obtaining an X-ray distribution transmitted through an object, a grid detecting system having a construction for obtaining information from a grid side by the action of inserting the grid for decreasing scattered rays into the apparatus, and detecting at least one of the presence or absence of the grid, the kind of the grid and the presence or absence of the replacement of the grid by the use of the construction, an image processing system for image processing and outputting image data collected by the image obtaining portion, and a memory portion preserving therein a plurality of sets of image processing parameters for controlling the image processing system. The image processing system selects the image processing parameters preserved in the memory on the basis of at least the result of the detection by the grid detecting system and executes image processing.

Abstract: A grid, for use with electromagnetic energy emitting devices, includes at least metal layer, which is formed, for example, by electroplating. The metal layer includes top and bottom surfaces, and a plurality of solid integrated walls. Each of the solid integrated walls extends from the top to bottom surface and having a plurality of side surfaces. The side surfaces of the solid integrated walls are arranged to define a plurality of openings extending entirely through the layer. At least some of the walls also can include projections extending into the respective openings formed by the walls. The projections can be of various shapes and sizes, and are arranged so that a total amount of wall material intersected by a line propagating in a direction along an edge of the grid is substantially the same as another total amount of wall material intersected by another line propagating in another direction substantially parallel to the edge of the grid at any distance from the edge.

Abstract: A radiographic apparatus is disclosed which controls a movement of a reciprocatingly moving grid so that the grid is not or less likely returned in the middle of exposure of an object to X rays. The probability that the object is still exposed to the X rays when the grid is moved in the vicinity of a turning point is thus substantially lowered. Therefore the probability that a resulting radiograph has no or less moire pattern due to the grid is substantially heightened.

Abstract: Disclosed is an X-ray imaging system that comprises a high ratio, high primary transmission anti-scatter grid in combination with a dynamic X-ray tube output function to eliminate or reduce gridline artifacts. Conventional X-ray imaging systems utilizing conventional anti-scatter grids generally require that the grid be moved a distance of at least 20 grid pitches to eliminate gridline artifacts. Through the use of the anti-scatter grid and dynamic output function described, such artifacts are eliminated or substantially reduced when the grid travels a short distance. Any function that has zero frequency components at positive integer multiples of the reciprocal of the grid repeat time will completely suppress gridline artifacts. Any function that is equal to the convolution of an arbitrary function with a rect function whose width is a positive multiple of the grid repeat time will fit this criterion, and its use will completely suppress gridline artifacts.

Abstract: The object of the present invention is to provide a satisfactory image at a desired imaging timing by implementing grid movement control according to the time response characteristics of the radiation generation function and a decrease in time delay from an imaging request to actual irradiation. In order to achieve this object, a control device controls the actual irradiation instruction timing for an irradiation device on the basis of a pre-irradiation delay time as a time between an instruction and irradiation of actual irradiation of the irradiation device.

Abstract: Method and apparatus for a radiographic image of an object obtained by a radiography apparatus containing an X-ray emitter, in which an anti-scatter grid placed between the object and a radiographic image receiver is displaced, on rectilinear translation in its plane, when acquiring the images, between a starting position and an arrival position, according to a time displacement law of reference, at a greater rate of displacement in proximity to a starting position and to the arrival position. A measurement of the energy received in the form of X-radiation by the receiver is used to modify the rate of displacement of the grid at every instant.

Abstract: A Potter-Bucky device for a radiation image recording apparatus in which an image recording medium is exposed to radiation which has passed through an object in order to record a radiation image of the object on the recording medium includes a grid which is movably supported between the object and the recording medium and is reciprocated parallel to the recording medium. A counter-weight is connected to the grid and is reciprocated in synchronization with the grid but in an opposite direction. Among other benefits and features, the disclosure reduces or eliminates vibrations produced by the reciprocating grid.

Abstract: Grid arrangement (1) for use with an X-ray apparatus (70) that is provided with an X-ray source and a recording element, it being possible, in operation, to place the grid arrangement (1) against the recording element and the grid arrangement being equipped to accommodate a flat grid (3) that comprises a multiplicity of elongated thin lamellae. The lamellae are placed essentially parallel to one another in a direction parallel to one surface of the grid (3), and the lamellae are oriented towards a focal axis a specific distance above the surface of the grid (3). The grid arrangement (1) further comprises drive means (8) which are equipped to move the grid (3) in a pendulum movement essentially about an axis of rotation and adjustment means (4, 10) for adjusting the axis of rotation of the pendulum movement to match the focal axis of the grid (3).

Abstract: An anti-scatter X-ray raster provides suppression of secondary scattered Compton radiation thus improving image contrast. The anti-scatter X-ray raster comprises a plurality of tubular channels made of an X-ray absorbing material. The tubular channels are spliced together to form a cellular structure. The largest cross size (d) of a singe channel its length (H) meet a relationship 2d/H>&thgr;c, where &thgr;c is a critical angle of total external reflection of X-rays from the material forming the walls of the tubular channels. The cross-section of the tubular channels need not be circular but may be, for example triangular or hexagonal. In a non-focused raster embodiment all of the longitudinal axis of the channels are parallel. In focused embodiments, the longitudinal axis of the channels are radially angled such that if extended they would meet at the X-ray source point.

Abstract: Disclosed is an X-ray imaging system that comprises a high ratio, high primary transmission anti-scatter grid in combination with a dynamic X-ray tube output function to eliminate or reduce gridline artifacts. Conventional X-ray imaging systems utilizing conventional anti-scatter grids generally require that the grid be moved a distance of at least 20 grid pitches to eliminate gridline artifacts. Through the use of the anti-scatter grid and dynamic output function described, such artifacts are eliminated or substantially reduced when the grid travels a short distance. Any function that has zero frequency components at positive integer multiples of the reciprocal of the grid repeat time will completely suppress gridline artifacts. Any function that is equal to the convolution of an arbitrary function with a rect function whose width is a positive multiple of the grid repeat time will fit this criterion, and its use will completely suppress gridline artifacts.

Abstract: Method and apparatus and computer programs and computer medium for improving quality of a radiographic image of an object obtained by an X-ray apparatus containing an antidiffusion grid, placed between the object and a receiver of radiographic images, The grid is displaced in rectilinear translation in its plane on pickup of the image, between two positions according to a time displacement law which is a continuous curve with a time precision of approximately ±10% presenting at least five separate parts, the displacement taking place at constant speed over at least two parts and at variable speed over at least one part.

Abstract: An X-ray scatter reduction grid includes a first layer having a plurality of cells. The cells have a perimeter formed of an X-ray absorbing material. The shape of the perimeters can vary, but a polygonal shape is preferred. The grid can also include other layers, each with their own cells. The cells of the subsequent other layers are larger than and offset from the cells of the prior layer. The increased size of the cells allows a primary ray passing through the center of a first layer cell to also pass through the center of a subsequent layer cell. This allows for a maximum of primary ray passthrough and a maximum of scatter absorption.

Abstract: A scattered ray removal grid that has an overall shape of constant spherical curvature. The scattered ray removal grid has radiation absorbing portions arrayed in a lattice configuration and radiation non-absorbing portions made of thermoplastic resin disposed between the radiation absorbing portions and can therefore be easily produced to have an overall spherical shape at low cost.

Abstract: The object of this invention is to provide an imaging apparatus capable of providing a high-quality image optimum for medical diagnosis or the like by an arrangement for preventing any degradation in image quality due to the influence of electromagnetic noise and vibration caused by grid movement. In order to achieve this object, as operation control in receiving radiation transmitted through an object by an image sensing element through a movable grid and reading the accumulated signal from the image sensing element, a control device stops moving drive of the grid after the end of radiation irradiation for the object, and after the stop of moving drive, starts reading the accumulated signal from the image sensing element.

Abstract: An X-ray image photographing apparatus includes an image obtaining portion for obtaining an X-ray distribution transmitted through an object, a grid detecting system having a construction for obtaining information from a grid side by the action of inserting the grid for decreasing scattered rays into the apparatus, and detecting at least one of the presence or absence of the grid, the kind of the grid and the presence or absence of the replacement of the grid by the use of the construction, an image processing system for image processing and outputting image data collected by the image obtaining portion, and a memory portion preserving therein a plurality of sets of image processing parameters for controlling the image processing system. The image processing system selects the image processing parameters preserved in the memory on the basis of at least the result of the detection by the grid detecting system and executes image processing.

Abstract: Method and apparatus for a radiographic image of an object obtained by a radiography apparatus containing an X-ray emitter, in which an anti-scatter grid placed between the object and a radiographic image receiver is displaced, on rectilinear translation in its plane, when acquiring the images, between a starting position and an arrival position, according to a time displacement law of reference, at a greater rate of displacement in proximity to a starting position and to the arrival position. A measurement of the energy received in the form of X-radiation by the receiver is used to modify the rate of displacement of the grid at every instant.

Abstract: An injection molded anti-scatter grid is fabricated from an engineered thermoplastic to form a focused x-ray absorbent framework defining a plurality of inter-spaces. The engineered thermoplastic has higher yield strength than conventional anti-scatter grid fabrication materials, which produces a structurally rigid grid that renders conventional fiber-like inter-space material unnecessary, and further allows the grid to be flexed in one or more directions to change an effective focal length of the grid. The engineered thermoplastic is loaded with high density particles in order to be x-ray absorbent, while still maintaining desired structural properties.

Abstract: Method and apparatus and computer programs and computer medium for improving quality of a radiographic image of an object obtained by an X-ray apparatus containing an antidiffusion grid, placed between the object and a receiver of radiographic images, The grid is displaced in rectilinear translation in its plane on pickup of the image, between two positions according to a time displacement law which is a continuous curve with a time precision of approximately ±10% presenting at least five separate parts, the displacement taking place at constant speed over at least two parts and at variable speed over at least one part.

Abstract: A radiation photographing apparatus has a radiation image receiving portion for receiving radiation transmitted through an object and obtaining a radiation transmission image, and a grid to be disposed on the object side of the radiation image receiving portion. The grid includes a scattered ray removing member or a radiation detector. The grid is constructed for movement also to the side opposite to the object side of the radiation image receiving portion.

Abstract: A radiographic apparatus is disclosed which controls a movement of a reciprocatingly moving grid so that the grid is not or less likely returned in the middle of exposure of an object to X rays. The probability that the object is still exposed to the X rays when the grid is moved in the vicinity of a turning point is thus substantially lowered. Therefore the probability that a resulting radiograph has no or less moire pattern due to the grid is substantially heightened.

Abstract: A bucky device and method including an X-ray image detector, an anti-scatter grid, a first chamber disposed to house the grid in an active position in which the grid is positioned upstream of the X-ray image detector in respect to x-ray impingement and a second chamber disposed to house the grid in a storage position in which the grid is positioned downstream of the X-ray image detector in respect to x-ray impingement.

Abstract: The object of this invention is to provide an imaging apparatus capable of providing a high-quality image optimum for medical diagnosis or the like by an arrangement for preventing any degradation in image quality due to the influence of electromagnetic noise and vibration caused by grid movement. In order to achieve this object, as operation control in receiving radiation transmitted through an object by an image sensing element through a movable grid and reading the accumulated signal from the image sensing element, a control device stops moving drive of the grid after the end of radiation irradiation for the object, and after the stop of moving drive, starts reading the accumulated signal from the image sensing element.

Abstract: The movement of an anti-scatter grid in a radiography apparatus is a continuous curve having point symmetry with respect to the point whose time coordinate is equal to half the exposure time, and for which the space derivative of the time variable has two linear portions which are symmetrical with respect to a symmetry axis passing through the middle of the range of movement of the grid. The grid is moved with a high rate of movement close to the starting position and the end position.

Abstract: This invention relates to a radiographic apparatus which comprises a radiographic image photographing unit for photographing a radiographic image of an object irradiated with radiation by a radiation generating device, a distance measuring system for measuring the distances or distance from the radiation generating device to the radiographic image photographing unit and/or the object, and distance information indicating means for indicating distance information obtained by the distance measuring system.

Abstract: A radiation anti-scatter device comprising a grid and a grid driver connected to the grid for unidirectionaly moving the grid with a variable grid velocity along a path between a starting and an end position, and a method of providing such grid motion. The variable grid velocity may have a velocity profile V1=k1t for a first period and then V2=k2t−m for a second period, where V1 and V2 are velocity, k1 and k2 are constants, t is time, and m is an exponent having a value greater than 0. The anti-scatter device may be a component of a direct radiographic diagnostic imaging system which includes an image-producing element having an array of radiation detectors aligned in rows, and where the anti-scatter device is a grid having vanes oriented at an angle to the detector rows. Radiation emission may be synchronized with the grid motion to optimize a radiograph for a particular grid, radiation source, or examination procedure.

Abstract: A grid enclosure for an X-ray cassette has a rugged construction, and is easy to us efficient in operation, with open corners therein to achieve the desired protection of an X-ray cassette.

Abstract: The present invention, in one form, is a system for reducing contribution of scatter signal to an image of an object constructed from projection data acquired during a computed tomography scan. The system includes an x-ray source which emits an x-ray beam toward a detector array. A collimator plate is movable with respect to the detector array. The system is configured to move the collimator between a first position and a second position. In the first and second positions, the collimator does not cover the detector array, i.e., the collimator does not collimate the x-ray beam impacting the detector array. When moving between the first and second positions, the collimator at least partially covers the detector array, i.e., the collimator at least partially collimates the x-ray beam impacting the detector array.

Abstract: By providing a movable grid for eliminating the scattered component of radiation entering a radiation image pickup unit and a controller for controlling the moving speed of the movable grid corresponding to variation of the intensity of the radiation, the grid can be controlled based on a predetermined radiation irradiating time.

Abstract: An apparatus for radiological examination is provided with the grid 16 that is driven in reciprocating motion in order to reduce the effect of radiation scattered by the body of the patient being irradiated. The grid 16 is connected to a counterweight 23, and is moved through a motion transmission mechanism that is of the crank and connecting-rod type so as to ensure a dynamic balancing of the oscillating masses. With this simple and accurate type of driving system, better quality radiographic images can be obtained under different adjustment and set-up conditions of the apparatus.

Abstract: A radiation image recording and reproducing system includes a conveyor which conveys a stimulable phosphor sheet along a predetermined circulation passage in an image recording section which is disposed on the circulation passage and records a radiation image of an object on the stimulable phosphor sheet by exposing the stimulable phosphor sheet to radiation through the object. At least one grid is provided in the image recording section and the position of the stimulable phosphor sheet in the image recording section relative to the grid with respect to the projecting direction in which the radiation is projected onto the stimulable phosphor sheet upon recording of the radiation image of the object is changed according to the amount of radiation to be scattered by the object.

Abstract: In an x-ray imaging system, an x-ray detector assembly includes an x-ray detector and a support assembly secured to the x-ray detector for supporting an antiscatter grid assembly. The x-ray detector preferably includes a matrix of crystal detectors. The support assembly includes a foam bezel having one or more magnets disposed therein. The antiscatter grid assembly includes an antiscatter grid secured to a metal frame. The one or more magnets disposed in the bezel are situated so as to align with the metal frame of the antiscatter grid assembly when the antiscatter grid assembly is coupled to the x-ray detector assembly. The strengths of the one or more magnets are such as to allow the antiscatter grid assembly to be removably secured to the x-ray detector assembly. Alternatively, the one or more magnets may be secured to the metal frame of the antiscatter grid assembly and corresponding metal plates may be placed in the support assembly.

Abstract: A cellular X-ray grid comprises a main grid portion having a plurality of cells separated from one another by a plurality of partitions, the main portion has on a plan view a side which extends parallel to a direction of movement of the grid during exposure, the cells having sides arranged so that the sides of the cells are not parallel to the side of the main portion which is parallel to the direction of movement of the grid and extend relative to the side of the main portion at such an angle as to erase an image of the cells on an X-ray picture during exposing with the movement of the grid, the cells contain gas or vacuum.

Abstract: The present invention resides in a Fourier filter to detect defects on semiconductor wafers. The present invention relates to a Fourier filter to detect defects on semiconductor wafers which is less susceptible to having the filter output affected by vibrations and which avoids the physical contact from conventional damping.

Abstract: In an x-ray diagnostics apparatus having a scattered radiation grid moveable in a plane, the movement of the scattered radiation grid ensues via a tumbling or wobble bearing arranged between a rotating drive and the scattered radiation grid. An advantage of this arrangement is that relatively long standstill times during the reversal of the grid movement are reduced. Moreover, the tumbling or wobble bearing can be economically manufactured and is less structurally complicated than a lever articulation.

Abstract: A filmless X-ray imaging system includes at least one X-ray source, upper and lower collimators, and a solid-state detector array, and can provide three-dimensional imaging capability. The X-ray source plane is distance z.sub.1 above upper collimator plane, distance z.sub.2 above the lower collimator plane, and distance z.sub.3 above the plane of the detector array. The object to be X-rayed is located between the upper and lower collimator planes. The upper and lower collimators and the detector array are moved horizontally with scanning velocities v.sub.1, v.sub.2, v.sub.3 proportional to z.sub.1, z.sub.2 and z.sub.3, respectively. The pattern and size of openings in the collimators, and between detector positions is proportional such that similar triangles are always defined relative to the location of the X-ray source.

Abstract: An x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury.

Abstract: A radiographic imaging system is comprised of a radiation source 12, a radiation adsorbing grid assembly 18, an image producing element 22 a controller 34, an exposure sequence start means 28 and a grid assembly oscillation means 20. The radiation source and grid define a subject receiving gap, wherein an object under examination is disposed, and through which the source propagates a beam of radiation onto the face of the image producing element. The controller recognizes when the exposure sequence start means is activated and starts the exposure sequence. The exposure sequence is comprised of an exposure preparation interval and an exposure interval. The exposure preparation interval is comprised of a radiation source preparation time and a point-in-time when the grid assembly oscillation commences oscillating the grid assembly.

Abstract: A X-ray imaging system has a moveable grid which rejects X-rays that were scattered by a body being imaged. During an X-ray exposure the grid is reciprocated to blur the shadow of the grid in the image. Upon commencement of an X-ray exposure, the grid is moved at decreasing rate in a first direction toward an end point of travel. When the grid is near the end point, the movement rate increases and continues at this faster rate before and after the grid reverses direction at the end point. A given distance after the direction reversal, the rate decreases to a slow constant rate.

Abstract: A radiographic grid includes a grid housing having first and second side walls, a first cover sheet disposed on the grid housing, and a plurality of x-ray radiation absorbing lamellae disposed between the first and second side walls of the grid housing. Each of the plurality of lamellae has at least one alignment tab protruding from a lateral edge thereof for engaging the cover sheet such that each of the lamellae are maintained in alignment with respect to each other.

Abstract: An improved bucky drive utilizes a reversible rotary motor which drives a screw received in a nut fixed to a bucky grid. A integrated control circuit board for the motor insures that the motor is quickly operated. In other features, the motor is a DC motor with a position sensor. A transistor speed control is utilized. The bucky system may be operated in either a semi-automatic or an automatic mode. The speed of the grid may be controlled. Further, other operational parameters of the system may also be controlled.

Abstract: A flexible elongated slatted grid structure is suspended between a pair of spaced apart grid support frames each of which is adapted for rotation about a transverse axis intermediate the suspended ends of the grid. Mechanical adjustment means provides equal but opposite angular motion of the frames to curve the grid along a circular path.

Abstract: A radiation image recording apparatus comprises a source of radiation and a radiation image recording medium located facing the radiation source. A first slit plate is composed of a radiation absorber and at least two parallel slits, through which the radiation passes. The first slit plate is located between the radiation source and an object, which object is placed between the radiation source and the radiation image recording medium. A second slit plate is composed of a radiation absorber and at least two parallel slits, through which the radiation passes. The second slit plate is located between the object and the radiation image recording medium such that the slits of the second slit plate may be parallel to the slits of the first slit plate.

Abstract: A method and apparatus for radiographic techniques using an x-ray source (13). The radiographed object (M) is subjected to a beam (X) of radiation which is employed for forming a radiographic image of the object (M) onto a film (25). Between the radiographed object (M) and the film (25) is utilized a grid assembly (20) that prevents the disturbing effect of backscattered radiation or secondary radiation generated in the radiographed object on the radiographed image. The grid assembly (20) comprises a grid plate (22) having several equidistantly spaced lamellas opaque to x-rays. The x-rays can pass in the direction of the beam axis between the spaces (24) of said lamellas to the film (25). The grid plate is reciprocatingly oscillated at a varying amplitude so that the stops and changes of travel direction (K.sub.1 . . . K.sub.

Abstract: Scanning slit radiography apparatus with a radiographic grid of the invention makes possible the X-ray imaging at an enhanced primary radiation transmission, yet at a reduced scatter transmission. By orienting long axes A of radiopaque strips 12 obliquely to the sweep S of the grid 1, the strips 12 being separated by air interspaces 13 can be performed with a sufficient own stiffness that no aluminum top and bottom covers are needed. The planes of downward lateral faces 12' intersect each other in an upward decentration line D.sub.+ and the planes of upward lateral faces 12" intersect each other in a downward decentration line D.sub.-. In a preferred embodiment of the invention the grid 1 is inclined during the sweep S so that the convergent line of the grid continues to pass through the tube focus.

Abstract: 1. A diagnostic x-ray machine including a reciprocating grid reduces grid lines, in the radiographic image, formed as a result of velocity variations in the reciprocation of the grid, principally at the points of grid reversal. An x-ray source produces a beam of x-ray radiation along a major axis directed through the body and to the grid. A reciprocating mechanism moves the grid within a plane perpendicular to the major axis between a first limit and a second limit and the x-ray beam is modulated synchronously with the grid motion to reduce the grid image at points of grid speed variation.

Abstract: A method and apparatus for improving imaging in an X-ray mammography machine having a controllable X-ray source incorporates apparatus for directing the X-ray beam in a preselected configuration onto at least a portion of a target area. The creation intensity of the beam is detected in each of a plurality of substantially equal segments of the target area and a first segment of lowest radiation intensity is identified. The X-ray source is adjusted to establish a predetermined radiation intensity in the identified first segment. Second segments are then identified each having a radiation intensity greater than a predetermined percentage of the radiation intensity in the identified first segment. The radiation intensity directed toward the identified second segments is then automatically attenuated by a control system responsive to the radiation intensity detected in the second segments.