Abstract: A multileaf collimator for use in a radiation system providing a radiation beam in a given beam direction, including a first layer of a plurality of radiation blocking leaves, the leaves being arranged adjacent one another so as to form two opposed rows of adjacently positioned leaves and being movable in a longitudinal direction (Y) which is generally transverse to the beam direction, defining a radiation beam shaping field between the opposed ends of the leaves, a second layer of a plurality of radiation blocking leave, the leaves of the second layer being arraigned adjacent one another as to form two opposed rows of adjacently positioned leaves and being movable in a cross-over direction (X) which is generally transverse to the beam direction and angled with respect to the longitudinal direction (Y), defining a radiation beam shaping field between the opposed ends of the leaves of the second layer.

Abstract: A dynamic IMRT scheme. A RAD ON/RAD OFF cycle is an IMRT segment. Every set of opposing leaves in the collimator produces an IMRT profile or track. According to such an embodiment, at least one of the opposing leaves moves toward the other to produce the given track. When a track is complete, the opposing leaves remain together until the end of the segment. The dose rate remains constant during the segment.

Abstract: An x-ray apparatus has an x-ray source and an x-ray receiver, the x-ray source being adjustable relative to a subject and emitting x-rays in the direction toward the x-ray receiver during the course of radiological exposures of the subject. The x-ray apparatus has an arrangement in the beam path of the x-rays for influencing the shape and/or the intensity profile of the x-ray beam, and this arrangement is dynamically adjustable during radiological exposures of the subject for influencing the shape and/or the intensity profile of the x-rays.

Abstract: A method for acquiring a radiographic image of an elongated object, comprising: positioning an elongated object between a source of x-rays and a digital image capture device having an imaging dimension which is less than a like dimension of said elongated object; wherein said image source is stationary and said source projects an x-ray pattern which encompasses said elongated object; moving said digital image capture device in a direction parallel to said known imaging dimension to sequential contiguous stationary positions to acquire a sequence of radiographic images of said elongated object; and moving an assembly of x-ray opaque material which is positioned between said source of x-rays and said elongated object, and which has an opening for allowing passage of x-rays, such that said opening is synchronized with the movement of said digital image capture device to facilitate acquisition of said sequence of radiographic images at said stationary positions.

Abstract: Aspects for verifying an accessory beam limiting device position for a radiotherapy treatment session are described. Included in a system aspect is a radiotherapy treatment device, the radiotherapy treatment device including an accessory holder. A beam limiting device for establishing a treatment area, the beam limiting device held in the accessory holder, is also included, along with a first controller for controlling the radiotherapy device and performing a treatment plan. A second controller positions the beam limiting device according to the treatment plan, wherein performance of the treatment plan by the first controller depends on provision of an accessory code to the first controller. The accessory code includes a resistor-pair combination value.

Abstract: A method and system for shaping a beam from a radiation delivery device includes a moving miniature multi-leaf collimator which can be moved into the field of radiation from the radiation device to shape the beam or moved out of the radiation field of the radiation device so that a second collimator can shape the beam. The movable miniature multi-leaf collimator comprises opposing banks of movable leaves to form a conformal shape when the collimator is within the radiation field. A translation or rotation mechanism can move the left and right leaf banks at the collimator away from and displaced significantly from the radiation beam of the radiation delivery device so that they will not intercept the radiation field. A second collimator device is then used to produce another independent beam shaping within the radiation field of the radiation device.

Abstract: A rotatable multi-element beam shaping device according to embodiments of the invention includes a first assembly, rotatable about a central axis through which a beam passes. The first assembly has a first and a second jaw adapted to move across the central axis to shape the beam. A second assembly, positioned below the first assembly, is also rotatable about the central axis, and has a third and a fourth jaw adapted to move across the central axis to further shape the beam. The first and the second assemblies, according to the invention, are separately controllable.

Abstract: A collimator for X-ray apparatus has an aperture defined by the edges of four movable flexible shutters. Each shutter can be moved independently of the other shutters; thus, the position and the size of the aperture can be adjusted at will. The shutters are moved by winding them onto drums; each drum is driven by a stepping motor. Springs bias the shutters towards the closed position of the collimator.

Abstract: The present disclosure provides an adjustable collimator for collimating a beam of energy emitted from a focal spot of a beam source. The collimator is particularly intended for collimating an x-ray beam of a computed tomography scanner after the x-ray beam has passed through a patient being scanned. The collimator includes two elongated parallel plates arranged side by side to define a collimating slit between the plates. At least one of the plates is movably relative to the other plate for varying a width of the collimating slit. The collimator also includes a movable cam operatively arranged with respect to the at least one movable plate such that movement of the cam in a first direction causes the width of the collimating slit to increase, while movement of the cam in a second direction causes the width of the collimating slit to decrease.

Abstract: In radiotherapy, a high quality imaging array may be placed after the patient and opposite the radiation source to be used during radiation treatment to verify operation of a shutter system or similar device and/or to compute dose delivered to the patient. A model of the patient may be used and inverted in order to estimate values of energy fluence prior to absorption by the patient and overlapping of the various radiation beams passing through the patient. A test pattern of shutter excitation to illuminate a single ray at a time provides a simple method of obtaining the necessary model. The dose from this test pattern may be subtracted from the subsequent radiation treatment so as to provide limited or no increase in total dose to the patient.

Abstract: The invention is intended to shorten a positioning time required for forming an irradiation area with high accuracy using a number of leaf plates, and to reduce physical and mental burdens imposed on patients. A multi-leaf collimator comprises leaf plate driving body each including a plurality of movable leaf plates and provided respectively on one side and the other side, the plurality of leaf plates of the leaf plate driver on one side and the plurality of leaf plates of the leaf plate driver on the other side being disposed in an opposing relation to form an irradiation field of a radiation beam between the opposing leaf plates. Each of the leaf plate driving body includes a motor provided in common to the plurality of leaf plates. Driving force of the motor can be transmitted to the plurality of leaf plates at the same time through a pinion gear, upper and lower air cylinders, and upper and lower guides. Also, the driving force can be cut off selectively for each leaf plate.

Abstract: A collimator for a therapeutic linear accelerator comprising first and second opposed arrays of individually longitudinally moveable elongate leaves, and a blocking element arranged transverse to the two arrays and moveable in that transverse direction, thereby to move into a gap between the tips of a leaf from the first array and a leaf from the second array. The blocking element and the two arrays can be in the same plane, thereby reducing the overall height of the device. As the tips of the leaves are usually profiled, it is preferred that the side edges of the blocking element are profiled to a complementary shape. The side edges of the leaves are usually non-vertical in order to allow for the divergence of the radiation beam. Each leaf will have a different angle. Accordingly, it is preferred that the tip of the blocking element has a variable angle, in order to match the angle of whichever leaf is adjacent.

Abstract: The present invention relates to a system and method for calibrating a radiation therapy device, such as a collimator. A method for calibrating a collimator according to an embodiment of the present invention is presented. The method comprises moving a leaf of a collimator; determining whether a distance between the leaf and a line approximately equals a predetermined measurement; and associating the predetermined measurement with a collimator specific count if the distance between the leaf and the line approximately equals the predetermined measurement.

Abstract: A multileaf collimator for use in a radiation system providing a radiation beam in a given beam direction, including a first layer of a plurality of radiation blocking leaves, the leaves being arranged adjacent one another so as to form two opposed rows of adjacently positioned leaves and being movable in a longitudinal direction (Y) which is generally transverse to the beam direction, defining a radiation beam shaping field between the opposed ends of the leaves, a second layer of a plurality of radiation blocking leave, the leaves of the second layer being arraigned adjacent one another as to form two opposed rows of adjacently positioned leaves and being movable in a cross-over direction (X) which is generally transverse to the beam direction and angled with respect to the longitudinal direction (Y), defining a radiation beam shaping field between the opposed ends of the leaves of the second layer.

Abstract: A multileaf collimator (12) for use in a radiation system (10) providing a radiation beam (20) in a given beam direction, including a first layer (30) of a plurality of radiation blocking leaves (32), the leaves (32) being arranged adjacent one another so as to form two opposed rows of adjacently positioned leaves (32) and being movable in a longitudinal direction (Y) (34) which is generally traverse to the beam direction so as to define a radiation beam shaping field (36) between the opposed ends of the leaves (32), a second layer (40) of a plurality of radiation blocking leaves (42), the leaves (42) of the second layer (40) being arranged adjacent one another so as to form two opposed rows of adjacently positioned leaves (42) and being movable in a cross-over direction (X) (44) which is generally traverse to the beam direction and angled with respect to the longitudinal direction (Y) (34) so as to define a radiation beam shaping field (46) between the opposed ends of the leaves (42) of the second layer (40)

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

Abstract: A contour collimator has a plurality of plate-shaped diaphragm elements movably arranged with respect to each other in a guiding block to form a contour diaphragm for a radiation beam emitted by a radiation source towards the collimator, and at least one drive for moving the diaphragm elements. A drive is associated with each diaphragm element with the drives of a group of diaphragm elements being substantially adjacent, and a driving transmission arranged between each drive and the associated diaphragm element.

Abstract: The present invention relates to a fast and accurate method for calculating fluence of a calculation plane over a patient. According to an embodiment of the present invention, only a subset of the collimator leaves are analyzed for the fluence calculation, thus reducing the number of calculations required. Additionally, pre-integrated values of scatter strips, associated with each point of the calculation plane, may be referenced in a lookup table. The use of these pre-integrated values allows the avoidance of adding the fluence contribution of each square on the scattering plane. Rather, pre-calculated values of a subset of the scattering plane (scatter strip) may be referenced and combined, thus reducing the number of calculations required for a final scatter contribution to a point on the calculation plane. Further, the thickness of the collimator leaves is considered in the fluence calculation, thus providing a more accurate model for the scatter contributions of points on the scattering plane.

Abstract: A system and method for dynamic subspace intensity modulation. Portions around the edges of a multi-leaf collimator-defined static radiation field are expanded or shrunk during part or all of the delivery of radiation at constant velocity. In order to match some or all of the sloping regions (502) of an intensity profile, the individual leaves (41, 42) of the multi-leaf collimator are moved at a fixed velocity over the sloping portions (502) of the intensity profile. By keeping the major portion of the field static and by only moving the leaves at one fixed velocity over a small subspace of the intensity profile, it is relatively easier to know what dose the patient receives and it is also relatively easier to resume treatment since it can be determined exactly how many more monitor units of radiation must be delivered and what the leaf positions were when the radiation was turned off.

Abstract: A conformal radiation therapy device is disclosed. A multi-leaf collimator is mounted adjacent the head of a linear accelerator. A pair of spaced guides which define predetermined cam grooves are supported by the patient table. The multi-leaf collimator includes a plurality of longitudinally slidable leaves. Each of the leaves includes a cam pin mounted in a respective cam groove. As the head and multi-leaf collimator rotate relative to the patient, the predetermined cam grooves acting through the cam pins slide the individual leaves to adjust a radiation window for controlling radiation to the patient.

Abstract: A controller of the cross sectional area and shape of an X-ray beam includes two or more disks disposed in the center of the path of the beam, each disk being radio-opaque except for a window centered on the beam. One or more of the disks has a tracks at each side of the window in which shutters can slide between positions in which they close or open the window and select the size and shape of the X-ray beam passed through the controller and a subject to an image intensifier or other X-ray utilization device. One of the disks has a cam track which is engaged by a cam following element attached to a shutter on the other disk. The disks are mounted for relative rotation by drive motors which causes the shutter with the cam follower to change position and alter the size or shape of the transmitted beam cross section. With the shutter in desired position the disks can be rotated together to reorient the shaped beam around its central axis.

Abstract: The accuracy of radiation therapy is enhanced with the blade collimator of the claimed invention. Particularly, this collimator includes a support device for supporting at least two sets of radiation attenuating blades in a single plane or layer. The blades are reciprocally movable within this support. Shaping of the therapy may be increased by constructing the blades to include a varying width increasing from the central blade toward the exterior blades.

Abstract: A system for applying radiation therapy includes a radiation source for emitting a radiation beam and includes redundant treatment field-defining arrays for shaping the radiation beam. The radiation beam is initially shaped by a multileaf collimator having a side-by-side arrangement of leaf pairs. The leaves are individually manipulable to define apertures between the leaves of a pair. Thus, the contour of an irregular treatment field can be precisely defined. The second field-defining array includes field-defining members that are individually connected to corresponding leaves of the multileaf collimator. Preferably, the connections are mechanical linkages and there is a one-to-one correspondence of the field-defining members and the leaves. Adjustment of a leaf simultaneously adjusts a position of a corresponding field-defining member. Also in the preferred embodiment, the second array is contained within a conically shaped housing that provides beam guidance.

Abstract: This invention relates to a novel dynamic collimator which can be adapted to a linear accelerator (LINAC). The collimator is such that the shape of the jaw arrangement, and therefore the collimated beam of X radiation from the LINAC, can be changed and conformed in a very flexible and versatile way. In a preferred embodiment of the invention, the collimator has three pairs of opposing, parallel jaws, each pair of jaws being moveable, under control, to open and close in variable amounts. Each set of pairs may be oriented at a 60.degree. orientation such that the open transmission area of the collimator has a hexagonal shape. Variations on this sixth jaw collimator, including larger numbers of jaws, also are included within the invention. The variety of shapes with such a variable hexagonal collimator is enormous. Irregular target volumes can be filled by beams of radiation that can be nested because of the hexagonal nature of the jaw configuration, giving it added conformal shaping capabilities.

Abstract: An X-ray examination apparatus includes a beam diaphragm (3) with an X-ray absorbing shutter (4, 31, 32) which is arranged between the X-ray source (1) and the X-ray detector (9) in order to intercept parts of the X-ray beam (2), thus forming a limited X-ray beam (7). The shutter (4, 31, 32) can be displaced according to different degrees of freedom by different rotations of control rings (21, 22, 41, 42, 47, 48) whereto the shutter (4, 31, 32) is coupled. Because the shutter (4, 31, 32) can be moved to practically any desired position within the X-ray beam (2), the beam diaphragm (3) can shape the cross-section of the limited X-ray beam (7) in such a manner that essentially only a part (5) of a patient (6) to be examined is exposed to X-rays.

Abstract: A multiple layer multileaf collimator for shaping a radiation beam. The collimator comprises first and second layers of a plurality of elongated radiation blocking leaves. The leaves of each layer are arranged adjacent one another so as to form two opposed rows of adjacently positioned leaves and are movable in a longitudinal direction (Y) which is generally traverse to the direction of the beam so as to define a radiation beam shaping field between the opposed ends of the leaves. The layers are arranged one above another in the beam direction and offset in a lateral direction (X) generally transverse to the beam direction and orthogonal to the longitudinal direction (Y) so that spaces between adjacent leaves of the first and second layers are positioned over and under, respectively, leaves of the second and first layers, respectively.

Abstract: An x-ray apparatus is provided which allows the diaphragm aperture and the diaphragm position to be precisely identified in a simple manner. For this purpose, a radiation imaging system is provided which produces an image of the aperture of the primary diaphragm on a radiation-electrical transducer, the radiation-electrical transducer on which the aperture is imaged being separate from the radiation detector on which the complete diagnostics image is produced. The radiation-electrical transducer is followed by evaluation electronics for forming electrical signals corresponding to the diaphragm aperture size and position.

Abstract: A triaxially controlled X-ray diagnostic apparatus comprises a support unit having a first arm, a second arm, and a third arm which are capable of rotation on three mutually orthogonal axes, an X-ray generator mounted on an end of the third arm for irradiating an object under examination with X rays, an image intensifier, mounted on the other end of the third arm so that it is opposed to the X-ray generator, for detecting X rays transmitted through the object to provide an optical image, a TV camera connected to the image intensifier for converting the optical image into a video signal to provide an X-ray image of the object, a display unit for displaying the X-ray image, and rotation correction means for making rotation correction on an X-ray image displayed on the display unit on the basis of angles of rotation of the first, second and third arms when they are rotated from their reference position.

Abstract: A gating device for a radiation apparatus has at least one diaphragm plate adjustable in the beam path of a radiation transmitter, the plate having at least one guide aligned obliquely relative to the longitudinal axis of the diaphragm plate and an adjustment mechanism is attached to the diaphragm plate for moving the diaphragm plate in a manner defined by its guide to adjust the position of the plate in the beam path.

Abstract: A primary radiation diaphragm for a radiation apparatus has at least one diaphragm plate which is adjusted in a plane extending perpendicular relative to the central ray of radiation. Each plate is provided with a single mount which engages a guideway disposed on the wall of the housing. Preferably, four plates are arranged in two pairs, with the first pair lying in a first plane and the second pair lying in a second plane extending parallel to the first pair, each of the plates of the pair has a single mount and the pair of plates of the first pair engage the same guideway, while the pair of the second plate engage a second guideway disposed on a wall of the housing extending at right angles to the first-mentioned wall.

Abstract: A shutter mechanism for collimating x-rays uses a frame to define an opening with two opposing interior edges. An elongated flexible band extends in sliding engagement about at least a portion of the periphery of the frame opening. A first shutter member made of an x-ray opaque material has a first end attached to the flexible band along the first interior edge of the frame. Similarly, a second shutter member made of an x-ray opaque material has a first end attached to the flexible band along the second interior edge of the frame. A drive means, such as a stepper motor, translates the flexible band relative to the frame to control the positions of the shutter members and the shutter aperture. In the preferred embodiment, the interior edges of the frame also include tracks that slidably engage the opposing edges of the shutter members for support.

Abstract: A common application of X-ray fluoroscopy is in monitoring the location of a catheter inside a body. Such catheters may be used for balloon angioplasty, laser ablation, or like procedures that are now often used in place of traditional invasive surgery. Reliable and fast determination of the tip location from the fluoro images using the digital image processing technique is required. The present invention relates to a method for tracking a catheter probe or similar object during a fluoroscopic procedure as may be utilized, for example, in conjunction with apparatus and methods that confine full X-ray dosage to a central area, compensating for the reduced X-ray dosage in the peripheral areas by computer imaging enhancement.

Abstract: A contour collimator for shaping a radiation beam for radiation therapy has two sets of radiation-impermeable lamellae disposed opposite each other, with each lamella being individually displaceable toward and away from its counterpart lamella in the other set. The sets of lamella are disposed between lateral walls of holder, at least one of which can be loosened and tightened. The lamellae are normally urged against each other by a spring force acting on each lamella. A user-manipulable mechanism is operable for displacing all of the lamellae in both sets away from each other, so that a form conforming to the desired contour can be placed between the lamellae. The mechanism is then moved to permit the spring force to act on each lamella, causing the lamellae to abut the form. The lamellae are then clamped in position.

Abstract: A method for applying a radiation treatment with an arbitrary isodose profile is disclosed. The treatment apparatus has a radiation source which generates a radiation beam with an axis. The apparatus also includes a collimator having a plurality of independently movable plates disposed in the path of the radiation beam and oriented in a direction perpendicular to said beam axis. Each set has two movable plates. Control signals are generated. Two plates within a set of plates are actuated independently in orthogonal directions during the treatment, in response to the control signals, causing the beam to change in width. The intensity of the beam is changed as a function of the position of the plates to generate an arbitrary beam profile. Exemplary profiles which may be generated included rotationally symmetric parabolic profiles and flat profiles.

Abstract: An X-ray simulating system for a radiotherapy planning disclosed by this invention includes an acquiring unit for acquiring an image showing a diseased part, a detecting unit for detecting the shape of the diseased part on the basis of the image acquired by the image acquiring unit, a calculating unit for calculating simulation data for radiation on the basis of first data including data related to the shape of the diseased part detected by the detecting unit and second data including data related to radiation conditions in radiotherapy, and a supplying unit for supplying the simulation data calculated by the calculating unit to a radiation therapy apparatus.

Abstract: A contour is determined in the X-ray image by an image processing unit in an X-ray examination apparatus. An arithmetic processor responsive to the processing unit determines the position of X-ray absorbing diaphragm slats which enclose a minimum area situated around the contour of an object image. The diaphragm slats are moved to the correct position by a drive unit. As a result, overexposure of the X-ray image in the intensifier tube is counteracted and the medical details in the image become more distinct. Image harmonization are realized using X-ray absorbing wedges. Placing the wedges in excessively light parts of the X-ray image enables the dynamic range to be increased at areas of interest. The position of the wedges is calculated on the basis of a dose calculation based on exposure time, the voltage and the current applied to the X-ray source, these quantities being applied to the arithmetic processor via a control unit.

Abstract: A system for applying radiation treatment under computer control is disclosed. The system has a radiation source, which generates a variable intensity radiation beam, and a collimator. The collimator has a plurality of movable plates disposed in the path of the radiation beam and is oriented in a direction perpendicular to the beam axis. The apparatus is capable of actuating the plates independently during the radiation treatment, in response to a first control signal. The beam changes in width when the plates are so actuated. The collimator is rotated in response to a second control signal. The intensity of the radiation beam may be varied as a function of the plate position. A total radiation dosage is applied during two intervals. The first interval precedes the collimator rotation, and the second interval follows the rotation.

Abstract: A primary radiation diaphragm for an x-ray tube has a first group of diaphragm plates disposed proximate the focus of the x-ray tube, and a second group of diaphragm plates disposed distal of the focus. Each group of diaphragm plates consists of two diaphragm plate pairs, the plate pairs in each group forming a parallelogram. The diaphragm plates in each plate pair are adjustable together, with reference to the longitudinal axis of the overall radiation diaphragm structure by a control element, so that a ray pyramid having a desired size is formed. A single first shaft is used as a control element for simultaneously adjusting the diaphragm plates in one plate pair in the first group and one plate in the second group, the first shaft engaging each of the plates in these respective plate pairs for that purpose. A second single shaft engages the diaphragm plates in the other plate pair in the first group and the other plate pair in the second group, for simultaneously adjusting those plate pairs.

Abstract: The invention has an X-ray emitting tube and a linear detector on opposite sides of a plane containing a strip to be measured and an electronic acquisition, measuring and control unit. A mask transversely moveable relative to the strip occludes radiation from the X-ray emitting tube which is not intercepted by the strip or which passes through the edge region of the strip. This device offers an improved degree of precision measurement near the edge of the strip.

Abstract: A multileaf collimator for use in therapeutic radiology treatment systems for producing irregular shaped radiation fields in order to shield normal tissue or critical organs. A multileaf collimator following the present invention includes leaves designed such that the collimator exhibits penumbra which is minimized and generally uniform for positions that are equidistant from the central axis of the radiation field. The shape of each leaf end includes an asymmetric central portion and a flat portion on either side of the central portion. The central portion is designed such that geometric penumbra and transmission penumbra are equalized. The flat portions on either side of the central portion are coincident with a tangent drawn from the edge of the radiation source to a reference plane when the leaf is in the fully retracted or fully extended positions.

Abstract: A method and apparatus for improving skin line viewing in a medical X-ray diagnostic system having an X-ray source for generating a scanning X-ray beam to image a target. In one form, the apparatus includes a first collimator positioned in the X-ray beam and having a rectangular shaped slit for passing the beam. A second collimator is positioned adjacent the first collimator and includes a plurality of spaced attenuation plates which can be moved over the slit in the first collimator. The attenuation plates are angles and tapered with respect to the slit. Control means is provided for locating the target within the slit and continuously driving the second collimator attenuation plates so as to intersect the edge of the target aligned with the slit.

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: An exposure apparatus includes a light source for exposing a wafer through a mask; a light blocking device being movable and effective to block light from the light source to limit an exposure zone; a positional deviation detecting system for detecting positional deviation between the mask and the wafer; and a drive control system for moving the light blocking device to execute position control therefor, on the basis of a detection signal from the positional deviation detecting system.

Abstract: An exposure apparatus for transferring a pattern of an original onto a workpiece, includes a blocking member for defining a rectangular exposure region with respect to at least one of the original and the workpiece, wherein the exposure for the pattern transfer can be effected with the exposure region defined by the blocking member. Plural detection systems detect a positional deviation between the original and the workpiece, each of which is disposed so as to be associated with at least one of four sides of the rectangular exposure region. Plural first movable stages each is provided so as to be associated with at least one of the four sides, and each is adapted to carry thereon one of the detection systems disposed to be associated with a corresponding side. Each first movable stage comprises a single-axis stage movable in a direction parallel to a corresponding side.

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 primary radiation diaphragm for use in a medical radiation application apparatus for gating the x-ray beam emitted by a radiation source onto a desired region has first and second diaphragm plates and an actuator for the diaphragm plates having two ranges of adjustment. The first diaphragm plate is adjusted within the first range of adjustment by movement of the actuator, and the second diaphragm rate is adjusted by moving the actuator within the second range of adjustment.

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: A method and device for producing flux equalized x-ray images for medical radiography through the use of a scanning fan shaped x-ray beam and a feedback control system which regulates the beam intensity at a multiple number of points along the fan beam to compensate for the x-ray attenuation variations of the patient.

Abstract: In a radiation therapy device isodose curves are adjusted both by a movable plate that is controlled during the irradiation and by a non-movable filter body in the radiation path. The filter body is located in such a manner that it has decreasing absorbability in the opening direction of the plate. On the other hand, the plate produces a decreasing effective dose in its opening direction. by superimposing the two effects, it is possible to have the isodose curve in the object of irradiation rise or fall in the opening direction, so that a wide range of variation in the possible isodose curves is obtained, without having to change the fixed filter body.

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.