Abstract: An x-ray diagnostics installation having a primary radiation diaphragm disposed in the beam path of an x-ray tube includes a control unit for the primary radiation diaphragm having an operator-manipulable setting element and associated circuitry which cause the primary radiation diaphragm to move in directions corresponding to the direction of movement of the setting element. Rotary motion of the setting element causes rotation of the primary radiation diaphragm, and pivoting of the setting element cause the primary radiation diaphragm to be moved in the corresponding direction of the pivot.

Abstract: X-ray exposure equipment which can effectively converge a synchrotron radiation, which tends to diverge to a great extent in a horizontal direction, to assure a sufficiently high intensity on a lithographic plane and can irradiate X-rays perpendicularly to a full lateral extent of the lithographic plane over an entire exposure area. The X-ray exposure equipment comprises a point X-ray source and a first reflecting mirror having first and second point focuses and disposed such that the first focal point coincides with the location of the X-ray source so as to focus X-rays to the second focal point. A second reflecting mirror is disposed such that the focus thereof substantially coincides with the second focal point of the first reflecting mirror so as to collimate X-rays received from the first reflecting mirror by way of the focusing property thereof in parallel to a principal optical axis of an optical system for X-rays which includes the first and second reflecting mirrors.

Abstract: A collimator assembly for removing selected radiation output from a specimen. The assembly includes collimator elements with each element having walls comprised of a first material covered by an inner layer of a second material which preferentially absorbs inelastic scattered radiation created in the first material.

Abstract: In order to perform stereoradiography, an X-ray apparatus utilizes an X-ray tube having a pair of X-ray focal points. The X-ray beams are alternately irradiated from the focal points toward an image intensifier through a patient and are limited by an X-ray beam limiting device. The device shapes the irradiated X-ray beams onto a circular detection surface of the image intensifier into a polygon such as octagon. The X-ray irradiation field on the detection surface can be circumscribed to a circular input window (i.e. effective input area), preventing the field from going beyond the detection surface. Thus, direct X-ray leaking over the image intensifier is avoidable.

Abstract: A first diaphragm arrangement is between a polychromatic X-ray radiator and an examination region for passing a primary radiation beam traversing the examination region on the generated surface of a cone. A detector arrangement comprising several detector elements receives radiation passed by the first diaphragm arrangement and a second diaphragm arrangement, which is located between the examination region and the detector arrangement and assigns to each respective detector element the scattered radiation which is scattered in a part of the primary radiation beam at a given scattering angle. The association between the individual sections of the primary radiation beam and the different detector elements is such that the second diaphragm arrangement has a slot-shaped opening and the shape of the slot-shaped opening and of the detector elements is adapted to the shape of a cross-section of the primary radiation beam.

Abstract: A collimator for use in an imaging system with a radiation point source is formed from a plurality of collimator plates stacked together. Passages in each collimator plate in conjunction with the respective passages in adjoining plates form a plurality of channels through the collimator. The channel longitudinal axes are aligned with selected orientation angles that correspond to the direct beam path from the radiation source to the radiation detectors. The collimator plates are made up of patterned sheets of radiation absorbent material or alternatively comprise patterned photosensitive material substrates coated with a radiation absorbent material. The cross-sectional shape of each channel corresponds to the cross-sectional shape of the radiation detecting area of the detector element adjoining the channel.

Abstract: A collimator for use in an imaging system with a radiation point source has a plurality of channels formed therein along longitudinal axes aligned with selected orientation angles that correspond to the direct beam path from the radiation source to the radiation detectors. The collimator comprises a photosensitive material coated with a radiation absorbent material. The cross-sectional shape of the channels corresponds to the cross-sectional shape of the radiation detecting area of the detector element adjoining the channel, and the sidewalls of the channel are smooth along their length.

Abstract: A method and apparatus for creating image information for objects inspect with penetrating radiation which utilizes a flying spot scanner of reduced mass. Objects are scanned with penetrating radiation along curved scan lines. The flying spot scanner which effects such scanning has a stationary absorber plate having a fixed slit in it which is curved, as well as a chopper wheel having radially oriented slits. As the chopper wheel rotates, the radially oriented slits traverse the projection of the radiation passing through the fixed slit, and because this slit is curved, the radial slits may be of reduced length, and the chopper wheel may be of reduced mass. The detected radiant energy is divided into pixels, and the pixels are addressed to a utilization means such as a memory or a display in such manner that the pixels which correspond to a scan line of the object define a curved line in the utilization means which has the same shape as the curved scanning line.

Abstract: A panoramic dental radiography system projects multiple vertical, fan-shaped radiation beams through a subject's teeth and onto multiple detectors, with each fan-shaped beam avoiding the subject's spine. The radiographic source and radiographic detectors are rotated about a vertical axis, so that the detected radiation may be tomographically processed to produce a panoramic image of the teeth. The multiple vertical fan-shaped radiation beams are projected on either side of the spine, to reduce the radiographic dosage to the spine and to prevent the spine from blurring the panoramic radiograph. The resulting multiple projections can be tomosynthetically processed to produce a three-dimensional image of tissues of diagnostic interest, free of image artifacts produced by irradiation of the spine.

Abstract: The system includes a frame provided with jaws (8, 9) for grasping the collimator. The collimator and the case include a system of retractable studs that co-operate with reaction members to retain the collimator (2) on the case (5). The jaws act on the studs (46) to detach the collimator from the case while simultaneously grasping the collimator. It is shown that by acting in this way, the collimator is permanently retained and simultaneously collimator installation and fixing operations are facilitated.

Abstract: A gamma ray collimator including a housing having first and second sections. The first section encloses a first section of depleted uranium which is disposed for receiving and supporting a radiation emitting component such as cobalt 60. The second section encloses a depleted uranium member which is provided with a conical cut-out focusing portion disposed in communication with the radiation emitting element for focusing the emitted radiation to the target.

Abstract: A method for manufacturing a single focus collimator in a high precision without increasing a cost for manufacturing. In this method, grooves are on a bulk block member first, and a metallic material having sufficient .gamma. ray shielding property such as lead is casted into the grooves formed on the bulk block member, and then the bulk block member with the metallic material casted into the grooves is immersed into a solvent capable of dissolving the bulk block member but not the metallic material, such that a collimator body formed by the metallic material in a shape of the grooves is obtained as the bulk block member is dissolved by the solvent. The sensitivity of the single focus collimator can be made substantially uniform over the entire effective view field by forming the grooves with such intervals that holes formed on the collimator body have larger size toward a center of the collimator body.

Abstract: An X-ray volume analysis method of crystalline defects of a part (11), comprises the steps of positioning the part in the plane situated at equal distance from the focus of an X-ray source and a focusing plane (14); illuminating the part from a punctual X-ray source (10) by a beam of a large spectral width .DELTA..lambda. and of determined angular opening .DELTA..theta., the opening .DELTA..theta. of the beam being fixed by .DELTA..theta..ltoreq..DELTA..lambda./2d.cos.theta., d being the interreticular distance for the considered reticular planes; orienting the part (11) to obtain the diffraction on a chosen family of reticular planes (30); and collecting and analyzing the X-ray beam near the focusing plane or beyond.

Abstract: This invention is a dynamic multivane electron arc beam collimator having collimation vanes, means for controlling the vanes, and local controllers at the collimation site which dynamically define an electron aperture which defines the electron field of an electron beam emitted by a linear accelerator during electron arc therapy. The collimator can be attached to or detached from the head of a linear accelerator. The collimator provides for improvement in electron arc therapy dose uniformity.

Abstract: At least one primary diaphragm comprises two elements displaceable so as to form a linear fan-shaped beam which is incident on an object to be examined. The elements form the slit-shaped aperture forming the fan beam in their normal X-ray beam forming position and are moveable to a respective, selectable limit position perpendicularly to the fan shaped beam in order to define and mark an examination zone greater in cross-section area than the fan beam with a light beam. Light incident on the examination zone is restricted by the diaphragm elements in their limit positions, thus marking the examination zone with the light beam. X-ray exposure of the object to be examined takes place only when the elements are between the two positions defining the examination zone of the primary diaphragm where its diaphragm elements occupy in their respective limit positions.

Abstract: A detector for detecting z-axis position in the plane of the fan beam of a computed tomography machine with respect to the detector array employs a pair of slotted masks over independent detector cells, the slots creating exposed widths that decrease and increase along their length. The intensity signals from the two detector cells so masked are subtracted to produce a z-axis position signal eliminating the effect of dark currents. Multiple cells may be ganged to reduce the effects of sensitivity variations among pairs of detector cells. The z-axis position signal may be used to control the z-axis position of the fan beam with respect to the detector array and to reduce the effect of the detector cell's variations in sensitivity.

Abstract: Tomographic imaging is implemented by providing a source of penetrating radiation, means for forming a pencil beam and sweeping the pencil beam over a line in space, a radiation detector and a beam length collimator. The beam length collimator lies outside of the sweep plane defined by the sweeping motion of the pencil beam and has a plane of symmetry which intersects the sweep plane at an angle which may or may not be a right angle. The beam length collimator defines a sensitive volume which has a dimension along the length of the pencil beam where the selected slice is defined by (or partly by) a dimension of the pencil beam. The combination of the beam length collimator and the pencil beam define a sensitive volume from which scattered energy can pass the collimator and be detected. The beam length collimator preferentially detects energy scattered by the sensitive volume.

Abstract: The ends of a tapered glass capillary are secured in relatively movable mounting blocks for application of axial tension to the capillary. This mounting enables the capillary to be pulled taut so that its axis is straight to facilitate propagation of X-rays. The capillary is coated to provide flexibility and strength. The ends of the capillary extend into their respective mounting blocks, with at least a portion of each end being stripped of the coating material. A bonding material contacts the glass and the coating material and secures both to their corresponding mounting blocks to hold the capillary in place when tension is applied and to provide shear strength for the capillary wall.

Abstract: A body is scanned by a fan-shaped X-ray beam for an X-ray shadow image. Per sector of the fan-shaped X-ray beam detection means deliver a signal which is a measure of the quantity of X-ray radiation instantaneously transmitted in the respective sector through the body. An attenuation device operates in conjunction with a slit-type diaphragm and regulates the quantity of X-ray radiation transmitted under the control of control signals per sector of the fan-shaped X-ray beam. The control signals are formed on the basis of the signals from the detection means. The attenuation device comprises one or more elastic X-ray radiation absorbing strips extending essentially parallel to the slit-type diaphragm. The attenuation device comprises controllable drive members to bring the strip or strips to an undulated state.

Abstract: Disclosed is a radiology system of the mammography type wherein there is provision for a radiation controller having a detector of X-radiation having gone through the breast to be observed, of the type having a converter of X-radiation into photon radiation and a photomultiplier tube for the amplifications of photons emitted by the converter. The invention lies in the fact that the converter is masked by a belt opaque to the photon radiation except in the zones for which variable dimensions are planned so as to get adapted to the different shapes of breasts. The belt is driven by a motor which is turned on and off at the practitioner's command, so that the appropriate zone is in correspondence with the converter.

Abstract: A radiographic apparatus includes an X-ray generator for radiating X-rays, two slit members sequentially arranged to oppose the X-ray generator, a subject being arranged between the slit members, and each of the slit members having at least one linear slit for narrowing down X-rays to obtain a slit-like X-ray beam, a slit member moving unit for moving the slit members in such a manner that an X-ray tube focal point and the slits of the slit members are always aligned with each other, and a cassette film for two-dimensionally recording a slit-like X-ray beam obtained by causing X-rays to pass through the object and the linear slits of the slit members.

Abstract: The invention relates to an arrangement for generating an X-ray or gamma beam with small cross-section and variable direction, having an X-ray or gamma emitter, from the focus of which a bundle of rays emerges, and a diaphragm arrangement, which cuts out a beam from the bundle of rays and comprises a hollow-cylindrical first diaphragm body which is rotatable about its axis of symmetry and has two mutually offset helical slits on the circumference. In this arrangement, an X-ray beam with at least approximately square cross-section is cut out on a relatively long hollow-cylindrical body with small diameter by the slits winding around the diaphragm body in at least one turn each and being shaped in such a way that at least one straight line runs through the slits towards the focus, the position of which line can be varied by turning the diaphragm body.

Abstract: A new and improved microfocus radiography system incorporating a novel x-ray collimating device for eliminating shadow anomalies caused by secondary radiation from materials within the path of x-rays emitting from an x-ray source. The improved system includes a body defining an opening through which primary radiation may pass from a focal spot x-ray source toward a sample, an x-ray window covering the distal end of the opening, x-ray detection means, and an internal collimator to suppress secondary radiation. The window is penetrable by primary radiation passing through the opening with negligible generation of secondary radiation. The collimator defines an aperture and is disposed along the path of the radiation between said focal spot and said window so as to attenuate any passing primary radiation not directly striking the x-ray window. The collimator is formed from a material having a low vapor pressure at temperatures and pressures at which the system is operated.

Abstract: An exposure compensation apparatus for use in a radiographic equipment to modulate local intensity of radiation. The exposure compensation apparatus comprises a detecting means to detect transmittance of radiation at a location of a radiated object, right-left reversion means to reverse a location arrangement of the transmittance data on a line of a predetermined direction, an averaging means to average a pair of the original and reversed transmittance data of a location to acquire an averaged transmittance, and a local intensity control means to control a local intensity compensation means of the radiographic equipment.

Abstract: In one embodiment, an x-ray neutron instrument includes an x-ray or neutron lens (10) disposed in a path for x-rays or neutrons in the instrument. The lens (10) comprises multiple elongate open-ended channels (12) arranged across the path to receive and pass segments of an x-ray or neutron beam (14). The channels (12) have side walls reflective to x-rays or neutrons of the beam incident at a grazing angle less than the critical grazing angle for total external reflection of the x-rays or neutrons, whereby to cause substantial focusing or collimation and/or concentration of the thus reflected x-rays or neutrons. In a different embodiment, a condensing-collimating channel-cut monochromator comprises a channel (22) in a perfect-crystal or near perfect-crystal body (20). This channel (22) is formed with lateral surfaces (24, 26) which multiply reflect, by Bragg diffraction from selected Bragg planes, an incident beam (28) which has been collimated at least to some extent.

Abstract: A device for measuring the pulse transfer of X-ray quanta which are elastically scattered in an examination zone, includes an X-ray source which is arranged on one side of the examination zone, a detector which is situated on the other side of the examination zone and which measures the energy of the X-ray quanta, and a rotationally-symmetrical diaphragm device which is arranged between the detector and the X-ray source. In a device of this kind a comparatively accurate determination of the pulse transfer is also possible for thick objects, because the diaphragm device is constructed so that the X-ray quanta emitted by the X-ray beam source are transmitted to the examination zone only on the envelope of a cone.

Abstract: Apparatus for directing and focusing X-rays by the new method of confinement is disclosed. A capillary having an inlet end and an outlet end with a generally tubular or rectangular inner wall surface defines a longitudinal central opening. The central opening is tapered inwardly from the inlet end to the outlet end. X-rays are directed into the inlet end at angles less than the critical glancing angle for the inner wall surface to direct X-rays through the capillary to a focus point near the capillary outlet end.

Abstract: In combination with a diagnostic CT scanner using radiant energy for imaging, an apparatus for therapeutically irradiating a target, comprising a mask that partially attenuates the radiant energy passing therethrough, but transmits through an aperture sufficient radiant energy for imaging. The mask, intermediate the radiant energy source and the target, passes an unattenuated portion of the radiant energy to irradiate the target. The cross-sectional shape and spatial position of the mask aperture can be selectively varied. A post-mask is aligned with the mask aperture and attenuates the radiant energy passing therethrough to an energy level essentially uniform with that of the radiant energy passing through the mask to permit continued imaging during therapeutic irradiation of the target. A method of using the invention in combination with a diagnostic CT scanner using radiant energy for imaging is also provided.

Abstract: A dynamic focusing device is provided for an X-ray scanner, the device comprising at least one detector module located in a position to receive, be illuminated by, and respond to X-rays. A source of X-rays is movable toward or away from the detector module. The module comprising a plurality of crystals each having a scintillation surface located in a common plane, with a plurality of septa separating the crystals. The septa have a height which is upstanding above the surfaces of the crystals far enough to reduce lateral X-ray scatter and to cast a shadow upon the surfaces of the crystals responsive to an illumination thereof from said X-ray source. The invention dynamically positions the detector module relative to the distance between the detector module and the source of X-rays in order to reduce substantially to a minimum any shadow in the X-rays cast by the septa upon the surfaces of the crystals.

Abstract: In apparatus for radiographic diagnostics an X-ray beam attenuated by an object to be examined is converted into a light image by means of an X-ray image intensifier tube. Inter alia as a result of the geometry of the X-ray beam and of the input screen of the X-ray image intensifier tube the intensity of the image decreases towards the edge (vignetting). By arranging a stray radiation grid, for example, in the form of a perforated plate of X-ray-absorbing material, for example, lead or tungsten, in the path of radiation between the X-ray source and the X-ray image intensifier tube, vignetting can be reduced by an adapted variation of the local transmission of the stray radiation grid.

Abstract: A focusing collimator has a plurality of corrugated strips which are built up in a stack. Within each stacking plane of interest, each strip is shaped in cross-section as a part of a different radial sector of a common predetermined annulus.

Abstract: A method of making a grid for x-ray radiography including the steps of forming grid patterns of x-ray opaque material on a plurality of sheets of x-ray transparent material, aligning the sheets in a stack, and bonding the sheets together to form a lightweight stacked grid.

Abstract: An effective ray beam includes an arc-shaped cut-out element having its open side facing in the direction toward the center of a ray beam. Via a variable arrangement of the arc-shaped cut-out element in a plane perpendicular to the ray beam, the effective ray beam can be individually adjusted to an arc-shaped object under examination.

Abstract: A contoured X-ray imaging system consists of an X-ray source and X-ray film holding cassette for taking X-ray pictures closely adjacent to a body surface without unnecessary exposure of adjacent body parts to X-rays. The X-ray cassette is contoured to the outline of a structure or a body part to evaluate it without the radiation spreading unnecessarily to the adjacent areas. The X-ray cassette is a thin flat box which has an edge wall contoured outline of the subject or an adjacent structure. The X-ray source and intervening shields or the like are each configured to project an X-ray beam which is contoured in the same contour as the film-holding cassette so that the X-rays reach the film in the same contour as avoid unnecessary exposure of adjacent portions of the body to the X-rays.

Abstract: A lens and collimator apparatus for focusing and increasing the intensity of an x-ray beam at a specimen point. A screen with an aperture of pupil diameter comparable and no larger than the x-ray transverse coherence length and no smaller that the specimen diameter focuses the x-ray beam by diffraction. The screen is positioned from the specimen plane proportional to the ratio of the square of the pupil diameter to the mean wavelength of the x-ray beam. A plurality of parallel screens can also be used.

Abstract: An x-ray tube is enclosed in a housing 14, with a detachable x-ray cone 22 having an outward extending flange member 42, a cone holder 18 for receiving the flange member 42, a latch button 50 projecting from the holder for selectively releasing the cone 22 from the holder 18, and a safety plate assembly 26. The safety plate assembly is mounted between the cone holder and the housing 14 and has first and second tabs 28 which project from a periphery of a planar portion 30 of the safety plate substantially at right angles therewith. Each tab 28 has a projection 34 that is directed inward toward the other end generally at right angles with the tabs whereby a resting place is provided for the released cone 22 until the cone is manually removed.

Abstract: The invention relates to the elimination of streak-like artefacts in slit radiography which are caused by an axial excursion of the rotary anode X-ray tube used for making the radiographs. These streaks can be eliminated by adapting the speed of displacement of the X-ray beam, the number of revolutions per unit time of the anode and the intensity profile of the radiation beam to one another so that for each point the intensity modulation in the half-shade area, caused by the periodic displacement of the focal point, is compensated for.

Abstract: A piezo-electric attenuation tongue system for slit radiography equipment comprises a number of tongues placed next to each other. The tongue system is manufactured by slitting a plate of piezoelectric material from one of the edges but leaving unslit a strip of the plate along the opposite edge.

Abstract: A collimator apparatus is disclosed for directing a high energy electron beam from an accelerator through an exit aperture and through a spaced and non-connected collimator tube in juxtaposition with a target area in a patient. The collimator tube is adjustably positioned and positionally maintained by jig structure supported independently of the accelerator structure. A rod type alignment device is releasably positionable in the collimator tube to define alignment of that tube by a novel method using traditional isocentric motions of a patient couch and accelerator gantry. Collimator tubes of varying diameters and exit configurations may be selectively utilized to accurately conform an electron beam to a particular target area and provide uniform irradiation over that target area.

Abstract: An x-ray video system for the transillumination of an examination subject has an x-ray system which generates a transillumination image of a patient using an x-ray beam having a central ray, a diaphragm for gating the x-ray beam which has a number of plates, each moveable relative to the central ray, a signal generator associated with each plate which generates a signal corresponding to the position of the associated plate relative to the central ray, a mixer for combining the plate position signals with the transillumination image, and a display which generates the transillumination image with the position signals mixed therewith in the form of marks on the transillumination image.

Abstract: A dynamic focusing device is provided for an X-ray scanner, the device comprising at least one detector module located in a position to receive, be illuminated by, and respond to X-ray. A source of X-rays is movable toward or away from the detector module. The module comprises a plurality of crystals each having a scintillation surface located in a common plane, with a plurality of septa separating the crystals. The septa have a height which is upstanding above the surfaces of the crystals far enough to reduce lateral X-ray scatter and to cast a shadow upon the surfaces of the crystals responsive to an illumination thereof from said X-ray source. The invention dynamically positions the detector module relative to the distance between the detector module and the source of X-rays in order to reduce substantially to a minimum any shadow in the X-rays cast by the septa upon the surfaces of the crystals.

Abstract: In a radiation therapy machine it is desirable to produce irregular radiation field shapes in order to shield critical organs not invaded by the tumor. A multileaf collimator is formed of a multiplicity of heavy metal bar leaves driven relative to frames which are driven relative to jaws of a rectangular field collimator by electric motors and flexible cables.

Abstract: The apparatus for local chemical analyses at the surface of solid materials by spectroscopy of X photoelectrons comprising an ultravacuum analysis chamber 1 wherein is housed the sample to be analyzed 2 which is connected to a manipulator 3 located outside said chamber 1, an analyzer 4 in the vicinity of the sample and an electron source 5 emitting an electron beam 10 is characterized in that it comprises between the electron beam 10 and the sample 2 which is a bulky solid material, a microsource of X photons 6 placed as close as possible to said bulky sample 2.

Abstract: A Soller slit and method of producing a Soller slit by forming a plurality of grooves in two identical ceramic blocks. The two blocks are then bound together with parallel blades of each block facing each other. The ceramic blocks can contain lead titanate.

Abstract: The diaphragm comprises at least one chamber in which there flows a deformable material that attenuates the radiation beam, the chamber being shaped so that the attenuating material can be introduced from outside the chamber and so that it can surround the passage zone of the beam inside the chamber in such a way that the surface of the passage zone varies constantly with the volume of the material present in the chamber.

Abstract: An x-ray detector system has a detector element disposed at the end of a channel formed by spaced collimator plates. The thickness of each collimator plate projected onto the detector element increases along the length of the collimator plates in the direction of radiation propagation through the channel. The projection (and thus the thickness) has a greatest value at a detector-proximate end of the plate. The edge regions of the detector element are thus shielded from x-radiation by the extended width collimator plates. The length of the absorption paths in the detector element thus are substantially the same, even given a detector element which is slightly obliquely disposed. Thus the shape of the portion of the detector surface effective for detecting radiation is substantially independent of slight changes in the focus position.

Abstract: A multichannel X-ray spectrometer includes an X-ray tube with a transmission target and a holder for a specimen placed opposite the target, and spectrometric channels arranged around the specimen. These spectrometric channels include, successively arranged downstream fluorescent X-rays of the specimen, a common inlet annular slit with a radius R, focusing analyzer crystals, outlet slits, and detectors of X-rays. The common annular slit is spaced from the reference surface of the holder to a distance h equal to 0.5 R, where R is 0.5 dD/2L, where d is the diameter of the outlet port of the transmission target, D is the diameter of the fo-fusing ring of the focusing analyzer crystals, and L is the length of one of the focusing analyzer crystals.

Abstract: A shielding apparatus for use in conjunction with an X-ray generator is disclosed. The apparatus comprises a shielding cone extending from the X-ray generator toward the object to be X-rayed, said cone comprising an upper cone portion detachably connected to the X-ray generator, a lower cone portion forming the base of the cone and a plurality of panels detachably connected to and extending between the upper and lower cone support portions. Additional shielding components are provided about the X-ray generator and secured to the shielded cone to further reduce the emission of stray X-rays.

Abstract: An X-ray imaging system has an X-ray source, an X-ray image detection section, an X-ray mask member, a drive unit, a memory, a calculating section, and an image output unit. An X-ray image is detected by the X-ray image detection section. The X-ray mask member has X-ray shielding regions, distributed in a predetermined pattern, which locally shield the X-ray. The mask member is driven by the drive unit so that it is inserted in or removed from an X-ray radiation field between the X-ray image detection section and the X-ray source, and is sequentially displaced to predetermined positions in the radiation field. The calculating section calculates scattered X-ray intensity distribution data based on a plurality of transmission X-ray data obtained by irradiating an object with X-rays with the mask member located at different positions in the radiation field, and transmission X-ray data obtained by irradiating the object with X-rays with the mask member located outside this field.

Abstract: Apparatus for treatment by radiation of an intracranial portion disposed at a predetermined region, comprises a linear accelerator for supplying a source of energetic electrons, and a collimator disposed adjacent the predetermined region for supplying an X-ray source of radiation to the predetermined region. The collimator includes a plurality of channels oriented toward the predetermined region. Each channel has a target which produces the X-ray radiation when the respective target is selectively exposed to the energetic electrons. The collimator also has a cover layer of radiation attentuation material having a low atomic or Z number and that extends over the outer surface of the collimator but leaves unexposed the plurality of channels. Preferably, the cover layer has a thickness at least equal to the range of the energetic electrons.A method of treating an intracranial portion with the apparatus of the present invention is also disclosed.