Imaging chain with miniaturized C-arm assembly for mobile X-ray imaging system

Abstract: A miniaturized C-arm and imaging apparatus (10) for use with X-ray diagnostic equipment and the like. An X-ray imaging system is coupled to a C-arm, including an X-ray source (C) and an image receptor (A) mounted upon opposing locations, respectively on the C-arm. The image receptor (A) includes a vacuum bottle type image intensifier (80). The image receptor (A) is characterized by an absence of fiber optic device, and the image intensifier (80) is characterized by an absence of micro channels therein. The C-arm is mass balanced about an axis of orbital rotation (16) and is pivotally coupled to an articulating arm assembly (18) supported upon a wheeled support base (32). The mass balance enables repositioning of the X-ray imaging system between an anterior-posterior view and an orthogonal lateral view with a single, orbital movement of the C-arm which also causes the views to define an imaging isocenter. The C-arm is preferably miniaturized to an approximate outside diameter of twenty-eight inches with a source-to-image distance of approximately fourteen inches.

Description: BACKGROUND OF THE INVENTION 1. The Field of the Invention. The present invention relates to a miniaturized support arm and imaging apparatus for use with X-ray diagnostic equipment according to the preamble of claim 1. 2. The Background Art. EP-A-0160749 describes an x-ray medical apparatus comprising a base structure having contact to the floor and a support which is movable against the base structure in a way that a support structure which carries on its one end an x-ray source and on the other end an x-ray receiving means can be manipulated in a three dimensional way. The support structure is rotatable around a first horizontal axis. The support structure is rotatably connected to support, the rotational axis being vertical to the lateral axis and horizontal with respect to the ground. EP-A-0488991 describes a method and apparatus for the production of radiographic x-ray images utilizing a portable hand-held and battery operated x-ray system. The x-ray source and the receiving part are mounted on a u-shaped housing adapted to house electronic subsystems therein. The hand-held system does not show any positioning means to position the x-rays with respect to the member to be analyzed. EP-A-0023051 describes an x-ray image intensifier which has an evacuated envelope and inside the envelope an input screen, an output screen, and a plurality of electrodes constituting an electron lens system inside the evacuated envelope. DE-A-4137724 describes a digital radiographic x-ray system to attain x-ray images of a patient's body comprising an image intensifier and a video camera coupled to the x-ray intensifier, whereby the x-ray source, the x-ray intensifier and the video camera are controlled by a micro processor system. GB-A-2098440 describes a medical apparatus according to the preamble of claim 1. DE-U-8906386 describes an x-ray diagnostic system comprising an x-ray source and an x-ray receiving means mounted on a C-shaped frame which is slidably connected to a bracket which is part of an L-shaped arm, whereby the whole assembly can be rotated around a horizontal axis. To attain mass balancing of the assembly with respect to the horizontal axis the L-shaped arm is formed in a way so as to include a counter weight responsible for mass balancing of the complete assembly. DE-U-8521246 describes a mobile x-ray diagnostic apparatus comprising a C-shaped frame carrying an x-ray source and an x-ray receiving means, the C-shaped frame being displaceable circumferentially about an axis perpendicular to a median plane of the C-shaped frame, whereby the C-shaped frame can be displaced in a horizontal and in a vertical direction. The C-shaped frame can further be rotate around a horizontal axis which is parallel to the median plane of the C-shaped frame. No mass balancing with respect to the rotation around this horizontal axis is foreseen. WO-A-9526419 describes an x-ray imaging system which includes an x-ray source and an x-ray image receptor. The source and the receptor are moveable simultaneously along a line parallel to a patient reclined on an examination table. The x-ray machine is readily transportable between and fixedly secured in a plurality of rooms in a hospital or other medical facilities. A rotation of a C-arm which carries the x-ray source and the x-ray receptor around a horizontal axis is provided. No mass balancing with respect to this rotation is foreseen. The particular field of extremities imaging refers to X-ray imaging of the smaller anatomical members such as arms, legs, hands and feet. Extremities imaging thus requires only a small imaging area which has prompted the long felt need for miniaturized X-ray devices capable of producing high quality images. As a result, the development of X-ray devices for extremities viewing has been driven by the competing purposes of economizing size and cost and maintaining high imaging quality. Responsive mainly to the need for economizing size and cost, miniaturized X-ray apparatus have been developed which are much smaller and less expensive than conventional X-ray apparatus. For example, U.S. Patent No. B1 4,142,101 (Reexamination certificate issued Feb. 19, 1991 to Yin) discloses an X-ray imaging chain having an image intensifier which utilizes a fiber optic minifier in combination with a micro channel plate (MCP) intensifier. The fiber optic minifier can be made small enough to enable the production of X-ray images from an input area which is 76 mm to 152 mm (three to six inches) in diameter. Designers have been able to utilize the fiber optic minifier to produce smaller X-ray devices appropriate in size for extremities imaging. However, such prior art X-ray systems, while somewhat useful because of .their smaller size, are nonetheless characterized by a number of distinct disadvantages. The fiber optic minifiers and MCP amplifiers used in miniaturized X-ray systems have not been able to produce state of the art optical imaging, ironically because the channels of the MCP amplifiers are too large. The resolution and contrast ratio of the X-ray image is limited by the number of channels present in the MCP amplifier. Simply put, the number of MCP channels and associated fiber optic fiber which can fit per corresponding square inch of input area is too small to produce state-of-the-art X-ray images. The resolution and contrast which result from such miniaturized X-ray systems fall well below acceptable levels of quality. The high resolution X-ray images of intracorporeal anatomy necessary to a physician's ability to diagnose and treat patients have thus been sacrificed in favor of smaller size and lower cost. In addition, the extremities imagers of the prior art are difficult to maneuver and cumbersome to use. OBJECTS AND SUMMARY OF THE INVENTION It is an object of the present invention to provide a miniaturized mobile X-ray imaging system which is more convenient to use. The above object is solved by providing an apparatus according to claim 1. Particular embodiments of the invention are the subject of the dependent claims. Additional advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the invention will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which: FIG. 1 is a perspective view of a mobile C-arm apparatus and X-ray imaging system made in accordance with the principles of the present invention; FIG. 2 is a schematic view of an image intensifier of the apparatus of FIG. 1; FIG. 3 is a perspective, schematic view of an articulating arm assembly of the apparatus of FIG. 1; FIG. 4 is a side view of an alternative embodiment of a C-arm assembly portion of the apparatus of FIG. 1; FIG. 5 is a frontal view of the C-arm assembly of FIG. 4; FIG. 6 is a perspective view of the apparatus of FIG. 1 in a folded, compact arrangement for storage; and FIG. 7 is a perspective view of an alternative embodiment of the apparatus of FIG. 6. DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS For the purposes of promoting an understanding of the principles in accordance with the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the illustrated device, and any additional applications of the principles of the invention as illustrated herein, which would normally occur to one skilled in the relevant art and possessed of this disclosure, are to be considered within the scope of the invention claimed. Referring now to FIGS. 1-6, there is shown a mobile C-arm apparatus, generally designated at 10. As explained in more detail below, the apparatus 10 is directed to a miniaturized C-arm assembly, designated generally as C-ARM-ASSEMBLY. The C-ARM-ASSEMBLY includes an X-ray source and an image receptor. The image receptor includes a vacuum bottle type image intensifier. The image receptor is characterized by an absence of fiber optic device, and the image intensifier is characterized by an absence of micro channels therein. Referring more particularly to FIGS. 1-2, an X-ray source C projects X-rays 11 onto the image receptor A. The image receptor A includes a vacuum bottle type image intensifier, designated generally at 80. As understood so those skilled in the field of image intensifiers, the image intensifier 80 includes a vacuum bottle 82 having a receiving surface 86. The receiving surface 86 is coated, preferably on its interior, with a scintillator layer 87. A photocathode 84 is disposed within the vacuum bottle 82. The scintillator layer 87 is an input area for receiving the X-rays 11 and producing visible light photons 13. The visible light photons 13 are transmitted onto the photocathode 84, which produces electrons 17 therefrom. The scintillator layer 87 and the photocathode 84 thus cooperatively form a suitable input means having in input area for receiving X-rays and producing electrons 17 from the X-rays. Focusing electrodes are coupled to the vacuum bottle 82, including side-channeling electrodes 88 and accelerating electrodes 90, coupled to appropriate power means (not shown). The side-channeling electrodes 88 are supplied with less voltage than the accelerating electrodes 90. By illustration only, the side-channeling electrodes 88 may be supplied with 550 V, and the accelerating electrodes 90 may be supplied with 1.3 to 3.5 kV. An output phosphor layer 92 is coupled to the vacuum bottle 80 and operates as a suitable output means having an output area for receiving the electrons and producing light therefrom. The image intensifier 80 operates as a suitable image intensification means for accelerating the electrons 17 from the input means 84 to the output means 92 while maintaining the electrons 17 under vacuum so as to produce an optical image from the electrons. As understood by those skilled in the relevant art, the photocathode 84 includes means for arranging the electrons 17 into a first ordered array 94 of electrons, and the focusing electrodes 88 and 90 are configured and arranged and powered in a manner sufficient to draw the electrons 17 toward the output phosphor 92 and rearrange the electrons into an inverted array relative the first ordered array. The focusing electrodes 88 and 90 are configured, arranged and powered in a manner known to those skilled in the field to operate also as minification means for further arranging the electrons 17 into a second ordered array 96 of electrons having an area reduced in size relative to the area of the first array 94. Thus, acceleration/amplification is accomplished at the same time as minification, all in a single step. The image receptor A is characterized by an absence of fiber optic devices, and the image intensification means 80 is characterized by an absence of micro channels therein. These elements combine with the miniaturized nature of the C-ARM-APPARATUS and articulating arm assembly 80 coupled to a wheeled base 32 as explained below in more detail, to achieve a miniaturized X-ray imaging device which is capable of higher image quality. The prior art X-ray devices which are used in conjunction with miniature support apparatus rely upon fiber optic bundles, which have been heated and pulled to form a narrow output end, to achieve minification. Unfortunately, the fiber optic minifiers and MCP amplifiers used in miniaturized X-ray systems have not been able to produce state of the art optical imaging, ironically because the channels of the micro channel plate (MCP) amplifiers are too large. The resolution and contrast ratio of the X-ray image is limited by the number of channels present in the MCP amplifier. Simply put, the number of MCP channels and associated fiber optic fiber which can fit per corresponding square inch of input area is too small to produce state-of-the-art X-ray images. The high resolution X-ray images of intracorporeal anatomy necessary to a physician's ability to diagnose and treat patients have thus been sacrificed in favor of smaller size and lower cost. In addition, the extremities imagers of the prior art are difficult to maneuver and cumbersome to use. Image quality is also sacrificed by the prior art devices because such devices accomplish minification and intensification in separate steps, and by manipulating light instead of electrons. The initial X-rays are transmutated into components of light which are first minified by the fiber optic bundle down to perhaps a 25.4 mm (one-inch) diameter in a first step. The minified light components are then passed through an MCP amplifier in essentially a one-to-one area ratio in a second step. Simply put, a large light image is channeled arid minified down to a small dim image with the fiber optic bundle, prior to amplification, after which the small, dim image is passed through a small image intensifier, about 1 to 1 in size. The output image will become a brighter image but still very small. Applicants' imaging chain thus involves the very different process of transmutating the X-rays 11 into electrons 17 instead of components of light, and minifying and accelerating the electrons 17 with the vacuum bottle 82 in a single step. These differences result in better resolution and contrast ratio in the final image. Applicants have thus discovered that image quality can be improved significantly in terms of resolution and contrast ratios by provision of the image intensifier 80 as described above. In addition, the photocathode 84 can be configured and dimensioned such that its input area has a diameter less than 152 mm (six inches), and preferably within a range of 102 mm (four inches) to 152 mm (six inches). The advantages of applicants' invention include the fact that image quality is limited only by crystal structure of the scintillator layer 86 and the photocathode 84. The resulting image resolution is extremely high, and is much better than the image resolution produced by the micro channel plates of the prior art devices. Applicants' invention also results in better contrast ratios. The phrase "contrast ratio" as used herein refers to the ratio of maximum output brightness to minimum output brightness, when a lead disk whose area is 10% of the input area produced by photocathode or input phosphor 84 is attached to the center of the entrance plane, as understood by those of ordinary skill in the relevant art. The electrons 17 are passed through the output phosphor 92 as an image of light. Light optics 94 and a CCD camera 96 may be utilized as known in the art to refine the image for viewing by a viewer's eye 98, as shown schematically in FIG. 2. The image receptor A as described above in relation to FIG. 2, when incorporated with the miniaturized C-ARM-ASSEMBLY and articulating arm assembly 18 of the present invention, offers the kind of convenient size and imaging quality which satisfy both competing and long felt needs of smaller size and high quality. The additional structures and embodiments described below are thus preferably used in conjunction with the image receptor A described above. Referring now more particularly to FIGS. 1 and 3-6, the C-ARM-ASSEMBLY is slidably mounted upon an L-arm or support arm D which is pivotally coupled to an articulating arm assembly supported upon a wheeled base, wherein the C-ARM ASSEMBLY is mass balanced about a single axis of orbital rotation 16. This mass balancing of the C-ARM-ASSEMBLY about the single axis of orbital rotation enables an operator to achieve an imaging isocenter with a single sliding orbital movement of the C-ARM-ASSEMBLY. A system which is "mass balanced" as that phrase is used herein refers to a system which is pivotable, orbitable, or otherwise rotatable about an axis 16 which coincides with the center of mass of the system. The C-ARM-ASSEMBLY and the support arm D collectively comprise a suitable support assembly comprising holding means and an X-ray source and an image receptor mounted upon opposing locations, respectively, on the holding means such that said X-ray source and image receptor define a source-to-image distance therebetween, wherein the holding means comprises the C-ARM-ASSEMBLY. The C-ARM-ASSEMBLY has a center of mass MC C-ARM-ASSEMBLY and includes a C-arm B having a substantially circular movement track 12 (FIG. 4) formed thereon. An X-ray source C and an image receptor A are mounted upon opposing locations, respectively, on the C-arm B such that the X-ray source and image receptor face each other as shown. The X-ray source C includes means therein for projecting X-rays 11 having a central beam 14 onto the image receptor A. The image receptor A can be an image intensifier or the like, as understood by those of ordinary skill in the art. The X-ray source C and the image receptor A define the source-to-image distance 14 therebetween. The C-ARM-ASSEMBLY is configured and dimensioned such that the source-to-image distance 14 is less than 762 mm (thirty inches). The source-to-image distance can also be less than 508 mm (twenty inches), and preferably less than 381 mm (fifteen inches). Applicants' preferred embodiment is directed to a C-arm B wherein the circular movement track 12 has an outside diameter of approximately 356 mm (fourteen inches) with the source-to-image distance 14 also being approximately 356 mm (fourteen inches). The meaning of the term "central beam" as used herein refers not only to a single center X-ray beam which defines a line extending from the X-ray tube focal spot 15 perpendicularly onto the center of the image receptor screen 55 as known to those skilled in the art, but shall also refer broadly to a cluster of X-ray beams central to the X-ray beams 12 and centered around the single center X-ray beam. Reference numeral 14 shall also refer to the distance between the focal spot 15 of X-ray source A and the image receptor C, known in the art as the source-to-image distance or SID. Applicants' image receptor screen 55 is circular, preferably with a diameter of either 102 mm (four inches) or 152 mm (six inches). A support arm D is disposed in slidable engagement with the circular movement track 12 such that the C-ARM-ASSEMBLY is selectively slidable relative to the support arm in orbital rotation about a single axis of orbital rotation 16. FIGS. 1 and 4 illustrate that the orientation of support arm D relative to the X-ray source C and image receptor A may vary, the respective positions of those elements being interposed in FIGS. 1 and 4. The circular movement track 12 is substantially common to a circle having a center point which coincides with the single axis of orbital rotation 16 such that said axis 16 remains substantially fixed relative to the said arm D for any position of the C-ARM-ASSEMBLY relative to said support arm. The term "circular" as used herein shall not be limited in meaning to an actual circle but shall also refer broadly to a partial circle, as in the case of the movement track 12. An articulating arm assembly, designated generally at 18, comprises a first arm 20 and a second arm 22 pivotally attached to both the first arm and the support arm D such that the support arm is selectively rotatable relative to the second arm 22 about an axis of lateral rotation 24 (FIG. 4) to selected lateral positions. The second arm 22 of the articulating arm assembly 18 comprises parallel linkage means as known in the art for moving the support arm D and C-ARM-ASSEMBLY relative to the first arm 20 from a first position to a second position such that the rotational axis 24 in the second position is substantially parallel in direction to the rotational axis 24 in the first position. The parallel linkage means is represented in FIG. 3 by a pair of rotational wheels 26 and a rod 28 pivotally coupled at its opposing ends 30 to each wheel 26, respectively, but may also comprise a four-bar parallel linkage as known in the art or the equivalent. It is to be understood that the phrase "articulating arm means" as used herein shall refer broadly to any means or member which can be pivotally attached to both the support arm D and the base support means 32, such as by nonlimiting example, the first and second arms 20 and 22 of FIG. 6, or the single arm 74 of FIG. 7, as explained below in more detail. The articulating arm means may thus comprise any number of one or more pivotally interconnected arms. A mobile base support means 32 is pivotally attached to the first arm 20 of the articulating arm assembly 18 for supporting the C-ARM-ASSEMBLY in a suspended position. The mobile base support means preferably comprises a base and wheels 34 rotatably mounted beneath the base to enable the base to roll on the wheels along a floor (not shown). The mobile base support means preferably includes an image processing and display work station as understood by those of ordinary skill in the art, designated generally at 36. The C-ARM-ASSEMBLY is mass balanced about the single axis of orbital rotation 16 such that the center of mass of the C-arm assembly CM C-ARM-ASSEMBLY substantially coincides with the single axis of orbital rotation 16 for any position of said C-ARM-ASSEMBLY relative to the support arm D along the circular movement track 12. Put another way and in reference to the three-dimensional coordinate system x, y and z having an origin at the single axis of orbital rotation 16 represented in FIG. 1: (1) (M B ) (D Bx ) = (M A ) (D Ax ) + (M C ) (D Cx ), and (2) (M B ) (D By ) + (M A ) (D Ay ) = (M C ) (D Cy ), where: M B = mass of C-arm B; D Bx = distance between CM B and the y-axis; CM B = center of mass of the C-arm B; M A = mass of image receptor A; D Ax = distance between CM A and the y-axis; CM A = center of mass of the image receptor A; M C = mass of X-ray source C; D Cx = distance between CM C and the y-axis; CM C = center of mass of the X-ray source C and the y-axis; D By = distance between CM B and the x-axis; D Ay = distance between CM A and the x-axis; and D Cy = distance between CM C and the x-axis. As shown most clearly in FIG. 5, the C-ARM-ASSEMBLY and the support arm D have a collective center of mass and are collectively mass balanced about the axis of lateral rotation 24 such that said collective center of mass substantially coincides with said axis of lateral rotation 24 for any rotational position of the support arm D relative to the second arm 22 of the articulating arm assembly 18 about said axis of lateral rotation 24. In reference to the three-dimensional coordinate system x', y' and z' having an origin at the axis of lateral rotation 24 represented in FIG. 1 and partially in FIG. 5: (3) (M C-ARM-ASSEMBLY ) (D C-ARM-ASSEMBLYz' ) = (M D ) (D Dz' ), where: M C-ARM-ASSEMBLY = mass of the C-ARM-ASSEMBLY; D C-ARM-ASSEMBLYz' = distance between CM C-ARM-ASSEMBLY and the y'-axis; CM C-ARM-ASSEMBLY = center of mass of the C-ARM-ASSEMBLY; M D = mass of support arm D; D Dz' = distance between CM D and the y'-axis; and CM D = center of mass of the support arm D. Of course, the equations (1), (2) and (3) apply to the specific configurations and positions illustrated in FIGS. 4-5. Other similar equations consistent with the principles of physics would apply to alternative configurations and positions. As can be understood by those having ordinary skill in the art, the C-ARM-ASSEMBLY is configured and arranged, in combination with the circular movement track 12 having a sufficient length, to enable the C-ARM-ASSEMBLY to be moveable along the circular movement track 12 in orbital rotation between a first orbital position and a second orbital position such that the central beam 14 in the second orbital position extends in a direction orthogonal to the central beam 14 in the first orbital position. The central beam 14 in the second orbital position passes through a first point of intersection of the central beam in the first orbital position 14, known in the art as an imaging isocenter. This first point of intersection is a first imaging isocenter. The phrase "imaging isocenter" refers to a fixed location of which two different X-ray images of the same area of anatomy may be taken along respective lines of sight. As understood by those skilled in the art of radiology, the imaging isocenter refers to the concept that, in both anterior-posterior and lateral views, the object of imaging interest is centered in the X-ray image of both views without being moved. The apparatus 10 can produce an imaging isocenter automatically without any adjustments other than a single movement of the C-ARM-ASSEMBLY between an anterior-posterior and lateral view. Preferably, the C-ARM-ASSEMBLY is configured and arranged such that the first point of intersection of the central beam 14 resides closer to the image receptor A than to the X-ray source A. In one particular preferred arrangement, the C-ARM-ASSEMBLY is configured and arranged such that the central beam 14 extends substantially vertically in the first orbital position and substantially horizontally in the second orbital position. The apparatus 10 may be designed with the C-ARM-ASSEMBLY being configured and arranged such that the central beam 14 in the second orbital position substantially coincides with the axis of lateral rotation 24. The support arm D is pivotally attached and configured at 60 (FIG. 3) relative to the second arm 22 of the articulating arm assembly to enable the C-ARM-ASSEMBLY to rotate about the axis of lateral rotation 24 between a first lateral position and a second lateral position such that the central beam 14 in the second lateral position extends in a direction orthogonal to the central beam 14 in the first lateral position. The central beam 14 in the second lateral position passes through a second point of intersection of the central beam 14 in the first lateral position, the second point of intersection being a second isocenter. If the central beam 14 could be made to coincide with the single axis of orbital rotation 16, and with the axis of lateral rotation 24 when horizontal, and assuming satisfaction of the equations (1), (2) and (3) above, then the first and second imaging isocenters would always coincide and be one and the same point for any combination of lateral and orbital position of the C-ARM-ASSEMBLY. Even if the central beam 14 does not coincide with the single axis of orbital rotation as in FIG. 4, the first and second imaging isocenters would coincide a majority of the time for any position of the C-ARM-ASSEMBLY if the apparatus 10 can be designed as suggested above wherein the horizontal position of the central beam 14 substantially coincides with the axis of lateral rotation 24. As a practical matter, the imaging apparatus must be as light as is possible such that it is presently quite difficult to build the apparatus 10 to achieve both (i) a mass balance of the C-ARM-ASSEMBLY about the single axis of orbital rotation 16, and (ii) the central beam 14 coinciding with the single axis of orbital rotation 16. However, applicants have discovered that the miniaturized C-ARM-ASSEMBLY of FIGS. 1-6, wherein the source-to-image distance 14 is less than 762 mm (thirty inches), can be built so that the central beam 14 is sufficiently close to the single axis of orbital rotation 16 that imaging isocentricity is achieved in some form for substantially all combinations of lateral and orbital positions of the C-ARM-ASSEMBLY. Preferably, the C-ARM-ASSEMBLY is configured and arranged such that the second point of intersection of the central beam resides closer to the image receptor A than to the X-ray source C. Also, preferably, the C-ARM-APPARATUS is configured and arranged such that the central beam 14 extends substantially vertically in the first lateral position and substantially horizontally in the second lateral position. In accordance with the miniaturized nature of the C-ARM-ASSEMBLY, it is preferred that the circular movement track 12 have a radius which is less than 508 mm (twenty inches), and most preferably less than 381 mm (fifteen inches). The C-arm B includes a circular inner circumference 40 having a radius of less than 489 mm (nineteen inches), and most preferably less than 356 mm (fourteen inches). Referring now more particularly to FIGS. 1 and 6, the apparatus 10 is pivotally manipulable into a compact arrangement for storage as shown. The support arm D and the C-arm B each include a first side panel 42 and 44 (FIG. 1), respectively. The mobile base support means 32 includes a front section 46 and a side section 48 which collectively form a corner section 50 therebetween. The corner section 50 is not necessarily a straight line but may zig-zag or otherwise deviate from a straight line as shown in FIGS. 1 and 6, but is still a corner section. The first arm 20 of the articulating arm assembly 18 is pivotally attached to the front section 46 of the base support means 32 at a first pivot point of attachment 52, and the C-ARM-ASSEMBLY and the articulating arm assembly 18 and the support arm D are configured and pivotally interconnected so as to be pivotally manipulable into a compact arrangement such that (i) the first arm 20 extends from the first pivot point of attachment 52 across at least a portion of the front section 46 of the base support means 32 so as to reside closely adjacent to said front section, and (ii) the second arm 22 extends from the first arm 20 across at least a portion of the front section 46 of the base support means 32 to the corner section 50 so as to reside closely adjacent to said front section 46, and (iii) the support arm D extends from a portion of the second arm 22 adjacent the corner section 50 across at least a portion of the side section 48 of the base support means 32 such that the first side panels 42 and 44 of the support arm D and C-arm B, respectively, reside closely adjacent to said side section 48, such that the second arm 22 and the support arm D collectively extend across at least a portion of the front section 46, around the corner section 50, and across at least a portion of the side section 48. It is to be understood herein the novel combination embodied in FIG. 6 may also accomplished with equivalent structures. For example, any curved arm member having opposing distal ends may be used in lieu of the circular C-arm B of FIG. 6 as part of a curved arm assembly. It is also to be understood that the C-ARM-ASSEMBLY and its contained X-ray imaging system can be rotatably repositioned, either orbitally about axis 16 or laterally about axis 24, with only a single joint adjustment. The term "joint" refers to any of the slidable and pivotal connections among the C-ARM-ASSEMBLY, support arm D, and articulating arm assembly 18. FIG. 3 shows most of the joints in schematic fashion, including pivotal joints 38, 52, 60, 62, and the wheels 26 and rod 28 schematic of the parallel linkage means. The slidable engagement between the support arm D and the C-arm B is also considered a joint. Referring now to FIG. 7, there is shown at alternative embodiment of the apparatus 10, designated generally at 70. The apparatus 70 includes many of the same structures of the apparatus 10 of FIGS. 1 and 6, such as the X-ray source C and image receptor A, the C-arm B and support arm D, front section 46, side section 48, corner section 50, and the image processing and display work station 36. However, the base support means 32 includes a rigidly attached and upwardly-extending stationary arm 71. The apparatus 70 further includes an alternative articulating arm assembly designated generally at 72, including a first arm 74 pivotally attached to the support arm D at rotational connection 76. The first arm is also pivotally attached to the stationary arm 71 at rotational connection 78. The first arm 74 extends from the base support means 32 (and preferably from the stationary arm 71) across at least a portion of the front section 46. The apparatus 70 is pivotally manipulable in a manner similar to that described above in connection with the apparatus 10 of FIG. 6, in that the first arm 74 and the support arm D collectively extend across at least a portion of the front section 46, around the corner section 50, and across at least a portion of the side section 48. Many of the advantages of the present invention accrue due to the C-ARM-ASSEMBLY being mass balanced about the single axis of orbital rotation 16, and the combination of the support arm D and the C-ARM- ASSEMBLY being mass balanced about the axis of lateral rotation 24. This configuration enables an operator of the apparatus 10 to produce an imaging isocenter using two orthogonal views which requires the manipulation of only one movement, and thus fewer steps than are required by the prior art miniaturized X-ray imaging systems. In addition, mass balancing about axes 16 and 24 allows those joints to move freely when moved by the operator and yet remain in place when no outside force is being applied to the assembly. As understood to those skilled in the relevant art, locking means 57 and 59 can be used to lock and release movement of some or all of the joints and the like represented schematically in FIG. 3. The compactability of the apparatus 10 illustrated in FIG. 6, combined with the mobility provided by the wheeled base 32 and the manipulability provided by the articulating arm assembly 18 provide the invention with numerous advantages in the field of miniaturized X-ray imaging systems. It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the scope of the present invention and the appended claims are intended to cover such modifications and arrangements.

Claims: A miniaturized support arm and imaging apparatus for use with x-ray diagnostic equipment, comprising: a support assembly comprising a C-arm assembly including a C-arm (B) having a substantially circular movement track (12) formed thereon, wherein an x-ray source (C) and an image receptor (A) are mounted upon opposing locations, respectively, on the C-arm such that said x-ray source (C) and image receptor (A) define a source-to-image distance (14) therebetween, wherein the x-ray source includes means for projecting x-rays (11) having a central beam onto the image receptor (A); and a support arm (D) disposed in slidable engagement with the circular movement track (12) of the C-arm (B) such that the C-arm assembly is selectively slidable relative to said support arm (D) in orbital rotation about a single axis of orbital rotation (16), said circular movement track (12) being substantially common to a circle having a center point which coincides with said single axis of orbital rotation (16) such that said single axis of orbital rotation remains substantially fixed relative to the support arm (D) for any position of the C-arm assembly relative to said support arm; articulating arm means (18) pivotally attached to the support arm (D) such that the support arm (D) is selectively rotatable relative to said articulating arm means (18) about a lateral axis (24) of rotation to selected lateral positions; and mobile base support means (32) pivotally attached to the articulating arm means (18) for supporting the support assembly in a suspended position, said mobile base support means (32) being moveable along a floor; wherein the image receptor (A) comprises image intensification means (80) characterized in that the C-arm assembly and the support arm (D) have a collective center of mass and are collectively mass balanced about the axis of lateral rotation such that said collective center of mass substantially coincides with said axis of lateral rotation (24) for any rotational position of the support arm relative to the articulating arm means about said axis of lateral rotation; and the image receptor (A) further comprises an input means (84,87) having an input area for receiving x-rays (11) and producing electrons from said x-rays; output means (92) having an output area for receiving the electrons (17) and producing light therefrom; and wherein the image intensification means (80) is adapted for accelerating the electrons from the input means (84,87) to the output means (92) while maintaining said electrons (17) under vacuum so as to produce an optical image from said electrons, said image intensification means (80) including a vacuum bottle (82) and focusing electrodes (88,90) coupled to said vacuum bottle (82). The apparatus as defined in claim 1, wherein the input means (84,87) includes means for arranging the electrons into a first ordered array (94) of electrons (88,90), and wherein the focusing electrodes are configured and arranged and powered in a manner sufficient to draw the electrons toward the output means (92) and rearrange the electrons into an inverted array relative to the first ordered array. The apparatus as defined in claim 1, wherein the input area has a diameter less than 152 mm (six inches). The apparatus as defined in claim 3, wherein the input area has a diameter within a range of 102 mm (four inches) to 152 mm (six inches). The apparatus as defined in claim 1, wherein the input means (84,87) includes means for arranging the electrons into a first ordered array (94) of electrons having a first area, and wherein the focusing electrodes (88,90) comprise minification means for rearranging the electrons into a second ordered array (96) of electrons having an area reduced in size relative to said first area. The apparatus as defined in claim 1, wherein the C-arm assembly has a center of mass and is mass balanced about the single axis of orbital rotation (16) such that the center of mass substantially coincides with the single axis of orbital rotation for any position of said C-arm assembly relative to the support arm (D) along the circular movement track. The apparatus as defined in claim 1, wherein the C-arm assembly is configured and dimensioned such that the source-to-image distance (14) is less than 762 mm (thirty inches). The apparatus as defined in claim 1, wherein the C-arm assembly is configured and dimensioned such that the source-to-image distance (14) is less than 508 mm (twenty inches). The apparatus as defined in claim 1, wherein the C-arm assembly is configured and dimensioned such that the source-to-image distance is less than 318 mm (fifteen inches). The apparatus as defined in claim 1, wherein the articulating arm means comprises parallel linkage means (26,28,30) for moving the support assembly relative to the base support means (32) from a first position to a second position such that the axis of lateral rotation in the second position is substantially parallel in direction to the axis of lateral rotation in the first position. The apparatus as defined in claim 1, wherein the C-arm assembly is configured and arranged, in combination with the circular movement track (12) having a sufficient length, to enable the C-arm assembly to be moveable along the circular movement track in orbital rotation between a first orbital position and a second orbital position such that the central beam in the second orbital position extends in a direction orthogonal to the central beam in the first orbital position. The apparatus as defined in claim 11, wherein the central beam in the second orbital position passes through a first point of intersection of the central beam in the first orbital position. The apparatus as defined in claim 11, wherein the C-arm assembly is configured and arranged such that the first point of intersection of the central beam resides closer to the image receptor (A) than to the x-ray source (C). The apparatus as defined in claim 11, wherein the C-arm assembly is configured and arranged such that the central beam (14) extends substantially vertically in the first orbital position and substantially horizontally in the second orbital position. The apparatus as defined in claim 14, wherein the C-arm assembly is configured and arranged such that the central beam (14) in the second orbital position substantially coincides with the axis of lateral rotation. The apparatus as defined in claim 1, wherein the support arm (D) is pivotally attached and configured relative to the articulating arm means (18) to enable the C-arm assembly to rotate about the axis of lateral rotation (24) between a first lateral position and a second lateral position such that the central beam in the second lateral position extends in a direction orthogonal to the central beam in the first lateral position. The apparatus as defined in claim 16, wherein the central beam (14) in the second lateral position passes through a second point of intersection of the central beam in the first lateral position. The apparatus as defined in claim 17, wherein the C-arm assembly is configured and arranged such that the second point of intersection of the central beam (14) resides closer to the image receptor (A) than to the x-ray source (C). The apparatus as defined in claim 16, wherein the C-arm apparatus is configured and arranged such that the central beam (14) extends substantially vertically in the first lateral position and substantially horizontally in the second lateral position. The apparatus as defined in claim 1, wherein the mobile base support means (32) comprises a base and wheels (34) rotatably mounted beneath the base to enable the base to roll on the wheels along a floor. The apparatus as defined in claim 1, wherein the mobile base support means (32,34) includes an image processing and display work station. The apparatus as defined in claim 1, wherein the circular movement track (12) has a radius which is less than 508 mm (twenty inches). The apparatus as defined in claim 22, wherein the radius of the circular movement track (12) is less than 381 mm (fifteen inches). The apparatus as defined in claim 1, wherein the C-arm (B) includes a circular inner circumference (40) having a radius of less than 483 mm (nineteen inches). The apparatus as defined in claim 24, wherein the radius of the circular inner circumference (40) is less than 356 mm (fourteen inches). The apparatus as defined in claim 1, wherein the support arm (D) and the C-arm (B) each include a first side panel (42, 44), and wherein the mobile base support means (32, 34) includes a front section (46) and a side section (48) which collectively form a corner section (50) therebewteen, and wherein the articulating arm means (20, 22) is pivotally attached to the base support means (32, 34) at a first pivot point of attachment, and wherein the C-arm assembly and the articulating arm means (20, 22) and the support arm (D) are configured and pivotally interconnected so as to be pivotally manipulable into a compact arrangement such that (i) the articulating arm means (29, 22) extends from the first pivot point of attachment across at least a portion of the front section (46) of the base support means (32, 34) to the corner section (50) so as to reside closely adjacent to said front section (46), and (ii) the support arm (D) extends from a portion of the articulating arm means (20, 22) adjacent the corner section (50) across at least a portion of the side section (48) of the base support means (32, 34) such that the first side panels (42, 44) of the support arm and C-arm reside closely adjacent to said side section (48), such that the articulating arm means (20, 22) and the support arm (D) collectively extend across at least a portion of the front section (46), around the corner section (50), and across at least a portion of the side section (48). The apparatus as defined in claim 1, wherein the support arm (D) and the C-arm (B) each include a first side panel (42, 44), and wherein the base support means (32, 34) includes a front section (46) and a side section (48) which collectively form a corner section (50) therebetween, and wherein the articulating arm means (20, 22) comprises a first arm (20) and a second arm (22) pivotally attached to both the first arm (20) and the support arm (D), said second arm (22) being pivotally attached to the front section (46) of the base support means (32, 34) at a first pivot point of attachment, and wherein the C-arm assembly and the articulating arm means (20, 22) and the support arm (D) are pivotally interconnected into a compact arrangement such that (i) the first arm (20) extends from the first pivot point of attachment across at least a portion of the front section (46) of the base support means (32, 34) so as to reside closely adjacent to said front section (46), and (ii) the second arm (22) extends from the first arm (20) across at least a portion of the front section (46) of the base support means (32, 34) to the corner section (50) so as to reside closely adjacent to said front section (50), and (iii) the support arm (D) extends from a portion of the second arm (22) adjacent the corner section (50) across at least a portion of the side section (48) of the base support means (32, 34) such that the first side panels (42, 44) of the support arm (0) and curved member reside closely adjacent to said side section (48), such that the second arm (22) and the support arm (D) collectively extend across at least a portion of the front section (46), around the corner section (50), and across at least a portion of the side section (48).

Inventors: ANDERTON R LARRY, CURTIS STEVEN E, SPRATT R BRUCE, ANDERTON, R. LARRY, CURTIS, STEVEN E., SPRATT, R. BRUCE
Applicants: OEC MEDICAL SYSTEMS INC, OEC MEDICAL SYSTEMS, INC.
Application year: 1996
Main classification: A61B6
IPC codes: A61B6