Abstract:
An anatomical imaging system of the sort having a fixed gantry and a rotating disc, with an adjustable angle of tilt and increased structural integrity, and with improved power transmission and position sensing.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATIONS 
       [0001]    This Patent Application: 
         [0002]    (i) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/027,433, filed Jul. 22, 2014 by Neurologica Corp. and Eric Bailey et al. for ANATOMICAL IMAGING SYSTEM WITH IMPROVED ROTATING SLIP RING (Attorney&#39;s Docket No. NEUROLOGICA-64 PROV); 
         [0003]    (ii) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/027,472, filed Jul. 22, 2014 by Neurologica Corp. and Eric Bailey et al. for ANATOMICAL IMAGING SYSTEM WITH TILTING TORUS, TILT BRAKE AND FAIL-SAFE BRAKE (Attorney&#39;s Docket No. NEUROLOGICA-68 PROV); 
         [0004]    (iii) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/027,444, filed Jul. 22, 2014 by Neurologica Corp. and Eric Bailey et al. for ANATOMICAL IMAGING SYSTEM WITH IMPROVED POSITION SENSOR (Attorney&#39;s Docket No. NEUROLOGICA-70 PROV); and 
         [0005]    (iv) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/027,420, filed Jul. 22, 2014 by Neurologica Corp. and Eric Bailey et al. for ANATOMICAL IMAGING SYSTEM WITH FIXED CUP-SHAPED GANTRY AND ROTATING CUP-SHAPED DISC (Attorney&#39;s Docket No. NEUROLOGICA-78 PROV). 
         [0006]    The four (4) above-identified patent applications are hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0007]    This invention relates to imaging systems in general, and more particularly to anatomical imaging systems. 
       BACKGROUND OF THE INVENTION 
       [0008]    In many situations it can be desirable to image the interior of opaque objects. By way of example but not limitation, in the medical field, it can be desirable to image the interior of a patient&#39;s body so as to allow viewing of internal structures without physically penetrating the skin. 
         [0009]    Computerized Tomography (CT) has emerged as a key imaging modality in the medical field. CT imaging systems generally operate by directing X-rays into the body from a variety of positions, detecting the X-rays passing through the body, and then processing the detected X-rays so as to build a three-dimensional (3D) data set and a 3D computer model of the patient&#39;s anatomy. The 3D data set and 3D computer model can then be visualized so as to provide images (e.g., slice images, 3D computer images, etc.) of the patient&#39;s anatomy. 
         [0010]    By way of example but not limitation, and looking now at  FIGS. 1 and 2 , there is shown an exemplary CT imaging system  5 . CT imaging system  5  generally comprises a torus  10  which is supported by a base  15 . A center opening  20  is formed in torus  10 . Center opening  20  receives the patient anatomy which is to be scanned. 
         [0011]    Looking next at  FIG. 3 , torus  10  generally comprises a fixed gantry  22 , a rotating disc  23 , an X-ray tube assembly  25  and an X-ray detector assembly  30 . More particularly, fixed gantry  22  is disposed concentrically about center opening  20 . Rotating disc  23  is rotatably mounted to fixed gantry  22 . X-ray tube assembly  25  and X-ray detector assembly  30  are mounted to rotating disc  23  in diametrically-opposing relation, such that an X-ray beam  40  (generated by X-ray tube assembly  25  and detected by X-ray detector assembly  30 ) is passed through the patient anatomy disposed in center opening  20 . Inasmuch as X-ray tube assembly  25  and X-ray detector assembly  30  are mounted on rotating disc  23  so that they are rotated concentrically about center opening  20 , X-ray beam  40  will be passed through the patient&#39;s anatomy along a full range of radial positions, so as to enable CT imaging system  5  to create a “slice” image of the anatomy penetrated by the X-ray beam. Furthermore, by moving the patient and CT imaging system  5  relative to one another during scanning, a series of slice images can be acquired, and thereafter appropriately processed, so as to create a 3D data set of the scanned anatomy and a 3D computer model of the scanned anatomy. In practice, it is common to configure X-ray detector assembly  30  so that multiple slices of images (e.g., 8 slices, 16 slices, 32 slices, etc.) may be acquired with each rotation of rotating disc  23 , whereby to speed up the acquisition of scan data. 
         [0012]    In practice, it is now common to effect helical scanning of the patient&#39;s anatomy so as to generate a 3D data set of the scanned anatomy, which can then be processed to build a 3D computer model of the scanned anatomy. The 3D data set and 3D computer model can then be visualized so as to provide images (e.g., slice images, 3D computer images, etc.) of the patient&#39;s anatomy. 
         [0013]    The various electronic hardware and software for controlling the operation of rotating disc  23 , X-ray tube assembly  25  and X-ray detector assembly  30 , as well as for processing the acquired scan data so as to generate the desired slice images, 3D data set and 3D computer model, may be of the sort well known in the art and may be located in torus  10  and/or base  15 . 
         [0014]    In many cases CT imaging system  5  is intended to be stationary, in which case base  15  of CT imaging system  5  is set in a fixed position on the floor of a room and a special motorized movable bed is provided to move the patient relative to CT imaging system  5  during scanning. More particularly, with a stationary CT imaging system  5 , the patient is brought to the location of CT imaging system  5 , the patient is placed on the motorized movable bed, and then the motorized movable bed is used to move the patient relative to CT imaging system  5  (i.e., to advance the patient into center opening  20  of CT imaging system  5 ) so that some or all of the length of the patient may be scanned by CT imaging system  5 . 
         [0015]    In other cases CT imaging system  5  is intended to be mobile so that the CT imaging system may be brought to the patient and the patient scanned at the patient&#39;s current location, rather than requiring that the patient be transported to the location of the CT imaging system. Scanning the patient with a mobile CT imaging system  5  can be highly advantageous, since it can reduce delays in patient scanning (e.g., the patient can be scanned in an emergency room rather than waiting to be transported to the radiology department) and/or it can allow the patient to be scanned without requiring movement of the patient (e.g., the patient can be scanned at their bedside in an intensive care unit, “ICU”). To this end, and looking now at  FIGS. 4 and 5 , base  15  may comprise a transport assembly  50  for (i) moving mobile CT imaging system  5  to the patient prior to scanning and (ii) moving the CT imaging system relative to the patient during scanning. More particularly, transport assembly  50  preferably comprises (i) a gross movement mechanism  55  for moving CT imaging system  5  relatively quickly across room distances, so that the CT imaging system can be quickly and easily brought to the bedside of the patient, such that the patient can be scanned at their bedside without needing to be moved to a radiology department, and (ii) a fine movement mechanism  60  for moving the CT imaging system precisely, relative to the patient, during scanning so that the patient can be scanned on their bed or gurney without needing to be moved onto a special motorized movable bed. 
         [0016]    In one preferred form of the invention, gross movement mechanism  55  preferably comprises a plurality of free-rolling casters, and fine movement mechanism  60  preferably comprises a plurality of centipede belt drives  63  (which can be configured for either stepped or continuous motion, whereby to provide either stepped or continuous scanning of the patient). Hydraulic apparatus  65  permits either gross movement mechanism  55  or fine movement mechanism  60  to be engaged with the floor, whereby to facilitate appropriate movement of mobile CT imaging system  5 . Thus, with a mobile CT imaging system  5 , the CT mobile imaging system may be pre-positioned in an “out of the way” location (e.g., in an unused corner of an emergency room) and then, when a patient requires scanning, the patient may be quickly and easily scanned at their bedside, by simply moving the mobile CT imaging system to the patient&#39;s bedside on gross movement mechanism  55  (e.g., casters  62 ), and thereafter moving the mobile CT imaging system during scanning on fine movement mechanism  60  (e.g., centipede belt drives  63 ). 
       Adjusting the Angle of the CT Scan Relative to the Body of the Patient 
       [0017]    It has also been recognized that it can sometimes be useful to adjust the angle of the CT scan relative to the body of the patient, whereby to create a CT image which is set at an angle that is not perpendicular to the longitudinal axis of the patient&#39;s body. By way of example but not limitation, it can sometimes be desirable to obtain a CT image of the anatomy at a non-perpendicular angle to the longitudinal axis of the patient, whereby to image a particular feature. This may be achieved by tilting the patient at an angle to the scanning axis of the CT imaging system (e.g., by using a tilting table so as to tilt the patient relative to the scanning axis of the CT imaging system). However, tilting the patient relative to the scanning axis of the CT imaging system can be undesirable in many situations (e.g., where the patient&#39;s condition makes it unsafe or undesirable to tilt the patient in a desired way). In such circumstances, it may be desirable to instead tilt the torus of the CT imaging system relative to the patient in order to obtain the desired CT image. 
         [0018]    One approach to tilting the torus of a CT imaging system relative to the patient is to attach a pair of large, arc-shaped tilt guides to the torus of the CT imaging system, and to run a chain over the arc-shaped tilt guides. The chain is, in turn, attached to a gear and motor so that rotating the chain causes the torus to tilt relative to the base of the CT imaging system. See, for example,  FIGS. 6 and 7 , which illustrate such an apparatus. 
         [0019]    However, it has been recognized that the provision and use of large arc-shaped tilt guides significantly enlarges the profile of the CT imaging system (i.e., by extending outwardly from the base of the CT imaging system) and can present a hazardous obstruction for personnel working around the CT imaging system. 
         [0020]    It has also been recognized that where the torus of the CT imaging system is to be tilted relative to the patient, it may be desirable to provide a brake or other means for locking the tilted torus in a particular tilted position. 
         [0021]    And it has been recognized that where the torus of the CT imaging system is to be tilted relative to the patient, it may also be desirable to provide an emergency braking system so as to prevent the torus (which is typically quite large) from “falling” or “swinging” if power to the CT imaging system should be interrupted and the tilting system should fail, since such unexpected movement of the torus could injure personnel operating the CT imaging system and/or a patient being scanned by the CT imaging system. 
         [0022]    Thus there is a need for novel apparatus for tilting the torus of a CT imaging system which minimizes the profile of the CT imaging system while maximizing the degree of tilt available for scanning. There is also a need for a novel brake or other means for locking the tilted torus in a particular tilted position. There is also a need for a novel emergency brake for maintaining the tilt of the torus in the event that power to the CT imaging system is interrupted. 
       Increasing the Structural Integrity of the Rotating Disc and the Associated Fixed Gantry 
       [0023]    It has been recognized that substantial advantages can be obtained if the time required to scan the patient can be reduced. For one thing, patients sometimes move during the scan, which can result in degraded scan images. A faster scan time means that there is a reduced possibility that the patient will move mid-scan. For another thing, some patient anatomy is normally in motion, e.g., a beating heart. A faster scan time can make it possible to “freeze” the moving anatomy so as to allow imaging of the moving anatomy. 
         [0024]    In general, there are two ways to reduce the time required to scan the patient. First, the X-ray detector assembly  30  can be configured to acquire more slice images with each rotation of rotating disc  23 , whereby to speed up the acquisition of image data. Thus, over time, so-called “8 slice machines”, “16 slice machines”, “32 slice machines”, etc. have been developed. Second, the speed of rotation of the rotating disc  23  can be increased, whereby to speed up the acquisition of image data. 
         [0025]    Unfortunately, increasing the number of slices acquired with each rotation of rotating disc  23 , and/or increasing the speed of rotation of the rotating disc  23 , can introduce design issues. For example, it may be desirable to increase the speed of rotation of rotating disc  23  (e.g., from 120 rpms to 240 rpms) so as to improve imaging speed. However, it has been found that increasing the speed of rotation of rotating disc  23  (e.g., from 120 rpms to 240 rpms) significantly increases the forces on rotating disc  23  and the components which are mounted to, and rotate with, rotating disc  23  (e.g., X-ray tube assembly  25  and X-ray detector assembly  30 ). 
         [0026]    By way of example but not limitation, it has been found that as rotating disc  23  is rotated at higher speeds (e.g., 240 rpms) about center opening  20 , greater centrifugal forces act on the components which are bolted to rotating disc  23 , with the centrifugal forces being directed perpendicular to the direction in which the components are bolted to rotating disc  23  (i.e., the centrifugal forces are directed radially whereas the components are bolted to rotating disc  23  axially). As a result, the components mounted to rotating disc  23  may flex at their mounting points, which may in turn cause rotating disc  23  to flex. When this occurs, the alignment between components used for imaging (e.g., the alignment between X-ray tube assembly  25  and X-ray detector assembly  30 ) may be compromised, resulting in a degradation of image quality. 
         [0027]    Thus there is also a need for a rotating disc (and associated fixed gantry) having greater structural integrity so as to provide increased stability for the components that are mounted to the rotating disc when the rotating disc is rotated at high speeds (e.g., 240 rpms). And there is a need for providing a new way for mounting components (e.g., X-ray tube assembly  25 , X-ray detector assembly  30 , etc.) to the rotating disc so as to mitigate the destabilizing effects of the centrifugal forces that are imposed on the components when the rotating disc is rotated. 
       SUMMARY OF THE INVENTION 
       [0028]    These and other objects of the present invention are addressed by the provision and use of novel apparatus for selectively tilting the torus of a CT imaging system which minimizes the profile of the CT imaging system while also maximizing the degree to which the torus of the CT imaging system may be tilted. 
         [0029]    The present invention also comprises the provision and use of novel apparatus for maintaining the tilt angle of the torus of a CT imaging system at a desired angle relative to the base of the CT imaging system after the torus has been tilted. 
         [0030]    The present invention further comprises the provision and use of a novel fail-safe brake for preventing the torus of the CT imaging system from moving (i.e., tilting) relative to the base of the CT imaging system in the event that power to the CT imaging system is interrupted. 
         [0031]    In one preferred form of the invention, there is provided apparatus for scanning a patient, said apparatus comprising: 
         [0032]    a base; 
         [0033]    a torus pivotally mounted to said base and carrying scanning apparatus; 
         [0034]    a planetary gear comprising a curved lower planet gear mounted to said base, a curved upper planet gear mounted to said torus, and a sun gear disposed between said curved lower planet gear and said curved upper planet gear; and 
         [0035]    a motor for rotating said sun gear; 
         [0036]    wherein rotation of said sun gear causes said sun gear to move longitudinally relative to said curved lower planet gear, and also causes said curved upper planet gear to move longitudinally relative to said sun gear, whereby to move said upper planet gear longitudinally relative to said lower planet gear; 
         [0037]    and further wherein longitudinal movement of said curved upper planet gear relative to said curved lower planet gear tilts said torus relative to said base. 
         [0038]    In another preferred form of the invention, there is provided a method for scanning a patient, said method comprising: 
         [0039]    providing apparatus comprising:
       a base;   a torus pivotally mounted to said base and carrying scanning apparatus;   a planetary gear comprising a curved lower planet gear mounted to said base, a curved upper planet gear mounted to said torus, and a sun gear disposed between said curved lower planet gear and said curved upper planet gear; and   a motor for rotating said sun gear;   wherein rotation of said sun gear causes said sun gear to move longitudinally relative to said curved lower planet gear, and also causes said curved upper planet gear to move longitudinally relative to said sun gear, whereby to move said upper planet gear longitudinally relative to said lower planet gear;   and further wherein longitudinal movement of said curved upper planet gear relative to said curved lower planet gear tilts said torus relative to said base;       
 
         [0046]    tilting said torus relative to said base by rotating said sun gear; 
         [0047]    positioning the object to be scanned within said torus; and 
         [0048]    scanning the object. 
         [0049]    The objects of the present invention are also addressed by the provision and use of a novel CT imaging system comprising a fixed cup-shaped gantry and a rotating cup-shaped disc which is positioned within the fixed cup-shaped gantry, whereby to provide enhanced structural integrity so as to provide increased stability for the components that are mounted to the rotating cup-shaped disc when the rotating cup-shaped disc is rotated. The present invention also comprises the provision and use of a new way for mounting components (e.g., X-ray tube assembly  25 , X-ray detector assembly  30 , etc.) to the rotating disc so as to mitigate the destabilizing effects of the centrifugal forces that are imposed on the components when the rotating disc is rotated, i.e., by mounting the components to the interior side wall of the rotating cup-shaped disc. 
         [0050]    In one preferred form of the invention, there is provided apparatus for scanning an object, said apparatus comprising: 
         [0051]    a fixed cup-shaped gantry; 
         [0052]    a rotating cup-shaped disc rotatably mounted at least partially within said fixed cup-shaped gantry; 
         [0053]    a detector element mounted to said rotating cup-shaped disc for detecting a signal; and 
         [0054]    a motor for rotating said rotating cup-shaped disc relative to said fixed cup-shaped gantry; 
         [0055]    wherein said detector element is configured to detect a signal while said motor is rotating said rotating cup-shaped disc relative to said fixed cup-shaped gantry. 
         [0056]    In another preferred form of the invention, there is provided a method for scanning an object, said method comprising: 
         [0057]    providing apparatus comprising:
       a fixed cup-shaped gantry;   a rotating cup-shaped disc rotatably mounted at least partially within said fixed cup-shaped gantry;   a detector element mounted to said rotating cup-shaped disc for detecting a signal; and   a motor for rotating said rotating cup-shaped disc relative to said fixed cup-shaped gantry;   wherein said detector element is configured to detect a signal while said motor is rotating said rotating cup-shaped disc relative to said fixed cup-shaped gantry;       
 
         [0063]    positioning the object to be scanned within said rotating cup-shaped disc; and 
         [0064]    detecting the signal using said detector element as said rotating cup-shaped disc rotates relative to said fixed cup-shaped gantry so as to create a scan of the object. 
         [0065]    The present invention further comprises the provision and use of a novel slip ring for providing electrical power to the rotating cup-shaped disc and/or to the components which are mounted to the rotating cup-shaped disc. 
         [0066]    In one preferred form of the invention, there is provided apparatus for scanning an object, said apparatus comprising: 
         [0067]    a fixed gantry; 
         [0068]    a rotating disc rotatably mounted to said fixed gantry; 
         [0069]    a detector element mounted to said rotating disc for detecting a signal; 
         [0070]    a motor for rotating said rotating disc relative to said fixed gantry; and 
         [0071]    a slip ring for transferring power and/or data between said fixed gantry and said rotating disc while said rotating disc is rotating, said slip ring being mounted to said rotating disc and comprising:
       an outer surface and an inner surface;   at least one conductive strip extending circumferentially about said outer surface of said slip ring for transferring power and/or data between said fixed gantry and said slip ring; and   at least one bus bar mounted to said inner surface of said slip ring for transferring power and/or data between said slip ring and said rotating disc, wherein said at least one bus bar is in communication with said at least one conductive strip, and further wherein at least a portion of said at least one bus bar extends along the axis of rotation of said rotating disc.       
 
         [0075]    In another preferred form of the invention, there is provided a method for scanning an object, said method comprising: 
         [0076]    a fixed gantry; 
         [0077]    a rotating disc rotatably mounted to said fixed gantry; 
         [0078]    a detector element mounted to said rotating disc for detecting a signal; 
         [0079]    a motor for rotating said rotating disc relative to said fixed gantry; and 
         [0080]    a slip ring for transferring power and/or data between said fixed gantry and said rotating disc while said rotating disc is rotating, said slip ring being mounted to said rotating disc and comprising:
       an outer surface and an inner surface;   at least one conductive strip extending circumferentially about said outer surface of said slip ring for transferring power and/or data between said fixed gantry and said slip ring; and   at least one bus bar mounted to said inner surface of said slip ring for transferring power and/or data between said slip ring and said rotating disc, wherein said at least one bus bar is in communication with said at least one conductive strip, and further wherein at least a portion of said at least one bus bar extends along the axis of rotation of said rotating disc;       
 
         [0084]    positioning the object to be scanned along the axis of rotation of said rotating disc; and 
         [0085]    detecting the signal as the rotating disc rotates relative to the fixed gantry so as to create a scan of the object. 
         [0086]    And the present invention comprises the provision and use of a novel position sensor for determining the rotational disposition of the rotating cup-shaped disc relative to the fixed cup-shaped gantry in real-time. 
         [0087]    In one preferred form of the invention, there is provided apparatus for scanning an object, said apparatus comprising: 
         [0088]    a fixed gantry; 
         [0089]    a rotating disc rotatably mounted to said fixed gantry; 
         [0090]    a detector element mounted to said rotating disc for detecting a signal; 
         [0091]    a motor for rotating said rotating disc relative to said fixed gantry; and 
         [0092]    a position sensor for determining the rotational disposition of said rotating disc relative to said fixed gantry, said position sensor comprising:
       a fixed encoder reader mounted to said fixed gantry; and   a rotating rotary encoder strip mounted to said rotating disc and extending circumferentially around said rotating disc;       
 
         [0095]    wherein said fixed encoder reader is disposed adjacent to said rotating rotary encoder strip such that said fixed encoder reader can read said rotating rotary encoder strip so as to determine the rotational disposition of said rotating rotary encoder strip relative to said fixed encoder reader, and hence the rotational disposition of said rotating disc relative to said fixed gantry. 
         [0096]    In another preferred form of the invention, there is provided a method for scanning an object, said method comprising: 
         [0097]    providing apparatus comprising:
       a fixed gantry;   a rotating disc rotatably mounted to said fixed gantry;   a detector element mounted to said rotating disc for detecting a signal;   a motor for rotating said rotating disc relative to said fixed gantry; and   a position sensor for determining the rotational disposition of said rotating disc relative to said fixed gantry, said position sensor comprising:
           a fixed encoder reader mounted to said fixed gantry; and   a rotating rotary encoder strip mounted to said rotating disc and extending circumferentially around said rotating disc;   wherein said fixed encoder reader is disposed adjacent to said rotating rotary encoder strip such that said fixed encoder reader can read said rotating rotary encoder strip so as to determine the rotational disposition of said rotating rotary encoder strip relative to said fixed encoder reader, and hence the rotational disposition of said rotating disc relative to said fixed gantry.   
               
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0106]    These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
           [0107]      FIGS. 1 and 2  are schematic views showing the exterior of an exemplary CT imaging system; 
           [0108]      FIG. 3  is a schematic view showing various components in the torus of the exemplary CT imaging system shown in  FIGS. 1 and 2 ; 
           [0109]      FIGS. 4 and 5  are schematic views showing an exemplary transport assembly for an exemplary CT imaging system; 
           [0110]      FIGS. 6 and 7  are schematic views showing related art apparatus for tilting the torus of a CT imaging system; 
           [0111]      FIGS. 8-17  are schematic views showing a CT imaging system which incorporates a novel planetary gear for tilting the torus of the CT imaging system; 
           [0112]      FIGS. 18-22  are schematic views showing a novel brake for selectively preventing the torus of a CT imaging system from moving; 
           [0113]      FIGS. 23 and 24  are schematic views showing a novel fail-safe brake for preventing the torus of a CT imaging system from moving in the event of a power interruption; 
           [0114]      FIGS. 25-27  are schematic views showing a novel CT imaging system formed in accordance with the present invention, wherein the novel CT imaging system comprises a fixed cup-shaped gantry and a rotating cup-shaped disc, and further wherein the novel CT imaging system comprises a novel rotating slip ring; 
           [0115]      FIG. 28  is a schematic view showing further details of the novel slip ring shown in  FIGS. 25-27 ; and 
           [0116]      FIGS. 29 and 30  are schematic views showing a novel position sensor formed in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Anatomical Imaging System with Tilting Torus, Tilt Brake and Fail-Safe Brake 
       [0117]    In accordance with the present invention, there is provided a novel apparatus for selectively tilting the torus of a CT imaging system which minimizes the profile of the CT imaging system while also maximizing the degree to which the torus of the CT imaging system may be tilted. 
         [0118]    The present invention also comprises the provision and use of novel apparatus for maintaining the tilt angle of the torus of a CT imaging system at a desired angle relative to the base of the CT imaging system after the torus has been tilted. 
         [0119]    The present invention further comprises the provision and use of novel fail-safe brake for preventing the torus of the CT imaging system from moving (i.e., tilting) relative to the base of the CT imaging system in the event that power to the CT imaging system is interrupted. 
         [0120]    Looking now at  FIGS. 8-17 , there is shown a novel CT imaging system  105  which generally comprises a torus  110  which is supported by a base  115 . A center opening  120  is formed in torus  110 . Center opening  120  receives the patient anatomy which is to be scanned. 
         [0121]    Torus  110  generally comprises a gantry  122  and a rotating disc  123 . Gantry  122  is secured to base  115  by a pair of pivoting connectors  124  located on either side of gantry  122 , such that gantry  122  (and hence torus  110 ) can pivot on pivoting connectors  124  relative to base  115 , whereby to tilt torus  110  relative to base  115 . Rotating disc  123  is rotatably disposed within gantry  122 , such that rotating disc  123  can rotate circumferentially around center opening  120  without moving gantry  122 . Rotating disc  123  generally comprises scanning components (e.g., the aforementioned X-ray tube assembly  25  and X-ray detector assembly  30 , etc.) which are mounted to rotating disc  123  circumferentially around center opening  120 , whereby to permit scanning of an object (e.g., a patient) disposed within center opening  120  (for the sake of clarity, the scanning apparatus is omitted from  FIGS. 8-17 ). 
         [0122]    As seen in  FIGS. 8-17 , CT imaging system  105  comprises a novel planetary gear  126  which may be used to selectively tilt torus  110  relative to base  115 . More particularly, planetary gear  126  generally comprises a curved lower planet gear  127  which is mounted to base  115 , a curved upper planet gear  128  which is mounted to gantry  122 , and a sun gear  129  which is rotatably disposed between lower planet gear  127  and upper planet gear  128 , such that the teeth of sun gear  129  are in constant contact with both lower planet gear  127  and upper planet gear  128 , as will hereinafter be discussed in greater detail. Sun gear  129  is mounted to a carrier  131  which is in turn slidably mounted to a slide  132  which is mounted to base  115 , such that carrier  131  (and sun gear  129  mounted to carrier  131 ) can move along slide  132  (and hence along base  115 ). A motor  137  ( FIG. 12 ) may be used to selectively rotate sun gear  129  (either clockwise or counterclockwise), as desired. 
         [0123]    By virtue of the foregoing construction, rotation of sun gear  129  by motor  137  causes sun gear  129  to “walk” along lower planet gear  127  as the teeth of sun gear  129  interface with the teeth of lower planet gear  127 . As sun gear  129  “walks” along lower planet gear  127 , carrier  131  moves along slide  132  (i.e., in the same direction that sun gear  129  “walks” along lower planet gear  127 ). At the same time, the rotation of sun gear  129  causes upper planet gear  128  to move relative to sun gear  129  (i.e., in the opposite direction that sun gear  129  is “walking” relative to lower planet gear  127 ). Hence, the effect of rotating sun gear  129  is effectively doubled (i.e., because sun gear  129  moves along lower planet gear  127  at the same time that upper planet gear  128  is moving along the moving sun gear  129 ). 
         [0124]    By way of example but not limitation, and looking now at  FIG. 15 , it will be appreciated that when sun gear  129  is centered relative to both lower planet gear  127  and upper planet gear  128 , torus  110  is disposed perpendicular to base  115  (i.e., torus  110  is not tilted). As sun gear  129  is rotated counterclockwise (from the angle of view of  FIG. 15 ), sun gear  129  walks clockwise along lower planet gear  127  while upper planet gear  128  moves counterclockwise on sun gear  129 , whereby to tilt torus  110  in a first clockwise direction relative to base  115  (see  FIG. 16 ). 
         [0125]    Looking next at  FIG. 17 , it will be seen that when sun gear  129  is rotated in a clockwise direction (as seen from the angle of view of  FIG. 17 ), sun gear  129  walks in the opposite direction (i.e., counterclockwise) along lower planet gear  127 , and upper planet gear  128  is moved counterclockwise on sun gear  129 . Hence, by virtue of rotating sun gear  125  in a clockwise direction, torus  110  is tilted in a second, counterclockwise direction relative to base  115 . 
         [0126]    Therefore, by selectively rotating sun gear  155  either clockwise or counterclockwise, and by controlling how far sun gear  129  walks along lower planet gear  127 , torus  110  may be tilted in the direction and to the degree (relative to base  115 ) which is desired. 
         [0127]    It will be appreciated that the degree to which torus  110  is permitted to tilt relative to base  115  is a function of the degree of curvature of lower planet gear  127  and upper planet gear  128 , as well as a function of the length of lower planet gear  127  and upper planet gear  128 . It will also be appreciated that, by virtue of the foregoing construction, permanent arc-shaped tilt guides which enlarge the profile of CT imaging system  105  are no longer necessary, inasmuch as lower planet gear  127  and upper planet gear  128  effectively combine to form a tilt guide that is the combined length of lower planet gear  127  and upper planet gear  128 , and which extend outboard of base  115  only when tilting is required and torus  110  is being actively tilted. This is a significant improvement in the art. 
         [0128]    It will be appreciated that it may be desirable to provide a brake for maintaining the tilt of torus  110  while CT imaging system  105  is used for scanning. To this end, and looking next at  FIGS. 18-22 , there is shown a brake  141 . Brake  141  generally comprises an actuator  142  having an actuating shaft  143 , and a wedge  144  secured to the free end of actuating shaft  143 . Actuator  142  is secured to a housing  146  which is securely mounted to base  115 . Housing  146  is disposed over actuating shaft  143  and a portion of wedge  144  so that wedge  144  selectively projects out of housing  146 . Wedge  144  is sized to make an interference fit with an arcuate groove  147  that is formed in gantry  122  when wedge  144  is moved toward gantry  122  by actuator  143 . Arcuate groove  147  comprises inclined side walls  148  which are contacted by wedge  144  such that when wedge  144  is driven into arcuate groove  147  by actuator  142 , arcuate groove  147  (and hence torus  110 ) cannot pivot relative to actuator  143  (and hence relative to base  115 ). 
         [0129]    In use, when it is desired to pivot (i.e., tilt) torus  110  relative to base  115 , actuator  142  is actuated so as to retract its actuating shaft  143  outwardly, away from torus  110 , and hence to withdraw wedge  144  out of arcuate groove  147 . Planetary gear  126  is then utilized to tilt torus  110  as desired relative to base  115  in the manner discussed above. When torus  110  has been tilted to the desired angle, actuator  142  is actuated so as to move actuating shaft  144  toward torus  110 , and hence to drive wedge  144  into arcuate groove  147  and thereby establish a secure interference fit between wedge  144  and groove  147 . When wedge  144  makes a secure interference fit with arcuate groove  147 , torus  110  is effectively “locked” at the angle at which it has been tilted. 
         [0130]    It has also been recognized that, in the event of a power failure, brake  141  could fail (e.g., actuator  142  may fail to force wedge  144  securely into arcuate groove  147 , thereby allowing torus  110  to “fall” or “swing” away from a given tilted position on pivoting connectors  124 . Because torus  110  is typically quite large, and because unexpected and uncontrolled falling/swinging of torus  110  may present a hazard to personnel operating CT imaging system  105  and/or to patients undergoing scanning by CT imaging system  105 , it can be desirable to provide a fail-safe brake for maintaining torus  110  in a tilted configuration in the event of such a power failure. 
         [0131]    To that end, and looking now at  FIGS. 23 and 24 , a fail-safe brake  151  may be provided. Fail-safe brake  151  generally comprises a gear  152  and a disc  153 , with a shaft  154  being disposed between gear  152  and disc  153 . A housing  156  covers at least some of fail-safe brake  151 , as will hereinafter be discussed in greater detail. Gear  152  and disc  153  are connected to shaft  154  such that when gear  152  rotates, disc  153  also rotates, and vice versa. Housing  156  comprises an end plate  157 , an armature  158  and a coil  159 . Disc  153  is disposed within housing  156  in a gap between end plate  157  and armature  158 . High-friction pads  161  (e.g., asbestos pads) are disposed on the sides of end plate  157  and armature  158  which face disc  153 . A spring  162  biases armature  158  toward disc  153  such that high-friction pad  161  contacts disc  153  under the power of spring  162  and pushes disc  153  toward the high-friction pad  161  carried by end plate  157 , whereby to cause disc  153  to be clamped therebetween and prevent rotation of gear  152 . When electric current is passed through coil  159 , coil  159  generates an electromagnetic field which pulls armature  158  toward coil  159  (and against the power of spring  162 ). When armature  158  is drawn toward coil  159 , disc  153  is free to rotate (and hence, shaft  154  and gear  152  are also free to rotate). By virtue of the foregoing construction, it will be appreciated that, if CT imaging system  105  should suffer a power failure, the electromagnetic field generated by coil  159  will fail, thereby causing spring  162  to bias armature  158  toward disc  153  such that high-friction pads  161  engage disc  153 , clamping disc  153  between end plate  157  and armature  158 . This action prevents rotation of disc  153  (and hence also prevents rotation of gear  152 ). 
         [0132]    In one preferred form of the present invention, fail-safe brake  151  is carried on the aforementioned carrier  131  such that gear  152  contacts lower planet gear  127  ( FIG. 23 ). Hence, when power is supplied to fail-safe brake  151  so that gear  152  is free to rotate, gear  152  will rotate when sun gear  129  rotates (i.e., when the tilt angle of torus  110  is changed). Conversely, when a power failure causes disc  153  to be clamped by fail-safe break  151  in the manner discussed above, gear  152  is unable to rotate, so that carrier  131  is unable to move and hence sun gear  129  is unable to move, whereby to lock the tilt angle of torus  110  until such time as electrical power is restored to CT imaging system  105 . Thus, fail-safe brake  151  maintains the tilt angle of torus  110  in the event of a power failure. 
       Anatomical Imaging System with Fixed Cup-Shaped Gantry and Rotating Cup-Shaped Disc 
       [0133]    In accordance with the present invention, there is provided a novel CT imaging system comprising a fixed cup-shaped gantry and a rotating cup-shaped disc which is positioned within the fixed cup-shaped gantry, whereby to provide enhanced structural integrity so as to provide increased stability for the components that are mounted to the rotating cup-shaped disc when the rotating cup-shaped disc is rotated and hence to provide improved image quality. The present invention also comprises the provision and use of a new way for mounting components (e.g., X-ray tube assembly  25 , X-ray detector assembly  30 , etc.) to the rotating disc so as to mitigate the destabilizing effects of the centrifugal forces that are imposed on the components when the rotating disc is rotated, i.e., by mounting the components to the interior side wall of the rotating cup-shaped disc. 
         [0134]    Looking next at  FIGS. 25-27 , there is shown a novel CT imaging system  205  which generally comprises a torus  210  which is supported by a base  215 . A center opening  220  ( FIG. 27 ) is formed in torus  210 . Center opening  220  receives the patient anatomy which is to be scanned. 
         [0135]    Still looking at  FIGS. 25-27 , torus  210  generally comprises a fixed cup-shaped gantry  222  and a rotating cup-shaped disc  223 . Fixed cup-shaped gantry  222  and rotating cup-shaped disc  223  are disposed concentrically about center opening  220 . 
         [0136]    Fixed cup-shaped gantry  222  comprises an inner cavity  271  for receiving rotating cup-shaped disc  223  therein. By forming the fixed gantry as a cup-shaped component, increased structural integrity is provided to fixed cup-shaped gantry  222 . 
         [0137]    Rotating cup-shaped disc  223  comprises an interior side wall  273  disposed concentrically about center opening  220 . By forming the rotating disc as a cup-shaped component, increased structural integrity is provided to rotating cup-shaped disc  223 . In one preferred form of the present invention, scanning components (e.g., the X-ray tube assembly  225  and X-ray detector assembly  230 , etc., shown schematically in  FIG. 25 ) are mounted to interior side wall  273  of rotating cup-shaped disc  223  with bolts  231  (also shown schematically in  FIG. 25 ) which extend substantially radially, as shown in  FIG. 25 . It should be appreciated that, by mounting such scanning components to interior side wall  273  of rotating cup-shaped disc  223 , centrifugal forces (i.e., forces that are generated when cup-shaped disc  223  is rotated) are directed radially outward toward interior side wall  273  of rotating cup-shaped disc  223 , i.e., in the same direction that the scanning components (e.g., the X-ray tube assembly  225  and X-ray detector assembly  230 , etc.) are bolted (e.g., with radially-extending bolts  231 ) to interior side wall  273  of rotating cup-shaped disc  223 . 
         [0138]    In other words, with the present invention, the scanning components (e.g., the X-ray tube assembly  225  and X-ray detector assembly  230 , etc.) are bolted (e.g., with bolts  231 ) to interior side wall  273  of rotating cup-shaped disc  223  by passing the bolts  231  radially outward, substantially perpendicular to the adjacent portion of interior side wall  273 . Thus, with the present invention, the centrifugal forces that are generated when cup-shaped disc  223  is rotated force the scanning components (e.g., the X-ray tube assembly  225  and X-ray detector assembly  230 , etc.) radially outward against interior side wall  273  of rotating cup-shaped disc  223 , with the scanning components being forced radially outward along the longitudinal axis of the bolts  231  securing the scanning components to interior side wall  273  of rotating cup-shaped disc  223 . 
         [0139]    As a result of this construction, the destabilizing effects of centrifugal forces on the scanning components that are mounted to interior side wall  273  of rotating cup-shaped disc  223  are mitigated, whereby to provide increased stability for the scanning components that are mounted to rotating cup-shaped disc  223 . 
         [0140]    In one preferred form of the invention, fixed cup-shaped gantry  222  comprises fixed gantry bearings  276 , and rotating cup-shaped disc  223  comprises rotating disc bearings  277 , whereby to facilitate rotation of rotating cup-shaped disc  223  within fixed cup-shaped gantry  222 . 
         [0141]    It should be appreciated that the increased structural integrity provided by forming the gantry as a cup-shaped gantry supplements the increased structural integrity provided by forming the rotating cup-shaped disc  223  as a cup-shaped disc, thereby further stabilizing rotating cup-shaped disc  223  when rotating cup-shaped disc  223  is rotated. Among other things, providing increased structural integrity for the fixed gantry and the rotating disc provides improved stability for the bearings mounted between the fixed gantry and the rotating disc, which results in increased image quality and extended bearing life. 
         [0142]    In one preferred form of the present invention, CT imaging system  205  utilizes a direct drive motor for turning rotating cup-shaped disc  223  relative to fixed cup-shaped gantry  222 . More particularly, in this form of the invention, fixed cup-shaped gantry  222  comprises a fixed coil  278  disposed circumferentially about center opening  220 , and rotating cup-shaped disc  223  comprises a plurality of permanent magnets  279  disposed circumferentially about center opening  220 , whereby to provide a direct drive motor for effecting rotation of rotating cup-shaped disc  223  relative to fixed cup-shaped gantry  222 . 
       Rotating Slip Ring 
       [0143]    The present invention further comprises the provision and use of a novel slip ring for providing electrical power to the rotating cup-shaped disc and/or to the components which are mounted to the rotating cup-shaped disc. 
         [0144]    In order to provide electrical power to rotating cup-shaped disc  223  (whereby to power the scanning components mounted to rotating cup-shaped disc  223 , e.g., X-ray tube assembly  225  and X-ray detector assembly  230 , etc.), a novel rotating slip ring may also be provided for continuously transmitting electrical power to rotating cup-shaped disc  223  while rotating cup-shaped disc  223  is rotating. 
         [0145]    More particularly, and looking now at  FIGS. 25-30 , a rotating slip ring  281  may be mounted to rotating cup-shaped disc  223 . Rotating slip ring  281  preferably comprises an outer surface  282  and an inner surface  283 . Outer surface  282  preferably comprises a plurality of concentric conductive strips  284  attached thereto for transmitting power and/or data from a connector  285  ( FIG. 27 ) through rotating slip ring  281  to inner surface  283 , and for transmitting data from inner surface  283  through slip ring  281  to connector  285 . Connector  285  is preferably mounted to fixed cup-shaped gantry  222 . 
         [0146]    In one preferred form of the invention, electrical bus bars  286  ( FIG. 28 ) are mounted to the inner surface  283  of rotating slip ring  281 , whereby to provide electrical power and/or data to the components mounted to rotating cup-shaped disc  223  while rotating cup-shaped disc  223  is rotated, and/or to off-load data from the components mounted to rotating cup-shaped disc  223  while rotating cup-shaped disc  223  is rotated. Electrical bus bars  286  preferably extend perpendicular to the plane of slip ring  281  (and axially along opening  220 ), whereby to facilitate easy access to electrical bus bars  286  from the interior of CT imaging system  205 . Preferably electrical bus bars  286  are secured to rotating slip ring  281  prior to mounting slip ring  281  within CT imaging system  205  so that slip ring  281  and electrical bus bars  286  may be manipulated as a unit during assembly and/or servicing of novel CT imaging system  205 . 
       Position Sensor 
       [0147]    And the present invention comprises the provision and use of a novel position sensor for determining the rotational disposition of the rotating cup-shaped disc relative to the fixed cup-shaped gantry in real-time. 
         [0148]    Looking next at  FIGS. 29 and 30 , if desired, a position sensor  287  may be provided for determining the rotational disposition of rotating cup-shaped disc  223  relative to fixed cup-shaped gantry  222  in real-time. Position sensor  287  preferably comprises a fixed encoder reader  288  and a rotating rotary encoder strip  289 . Fixed encoder reader  288  is preferably mounted to fixed cup-shaped gantry  222  and reads rotating rotary encoder strip  289 , which is mounted to, and extends circumferentially around, rotating cup-shaped disc  223 . Fixed encoder reader  288  may comprise any suitable encoder reader known in the art (e.g., an electrical encoder reader, a magnetic encoder reader, an optical encoder reader, etc.) for pairing with a suitable rotating rotary encoder strip  289 . 
         [0149]    It should be appreciated that, by mounting fixed encoder reader  288  directly to fixed cup-shaped gantry  222 , and by mounting rotating rotary encoder strip  289  directly to rotating cup-shaped disc  223 , the absolute rotational disposition of rotating cup-shaped disc  223  can be determined at any point in time. This is a significant improvement over other approaches which typically rely on a “home” marker located on the drive shaft of the motor used to rotate the rotating disc, since reading a single “home” marker on the drive shaft of the motor requires an extrapolation to determine mid-rotation positioning and can lead to inaccuracies if there is any slippage between the drive shaft of the motor and the rotating disc. 
       Application to Other Types of Scanning Systems 
       [0150]    It should be appreciated that the present invention is not limited to use in medical applications or, indeed, to use with CT machines. Thus, for example, the present invention may be used in connection with CT machines used for non-medical applications, e.g., with CT machines used to scan inanimate objects. Furthermore, the present invention may be used with non-CT-type scanning systems. Thus, for example, the present invention may be used in conjunction with SPECT machines, MRI machines, PET machines, X-ray machines, etc., i.e., wherever it is desirable to tilt the scanning machine relative to the patient. 
       Modifications 
       [0151]    It will be appreciated that still further embodiments of the present invention will be apparent to those skilled in the art in view of the present disclosure. It is to be understood that the present invention is by no means limited to the particular constructions herein disclosed and/or shown in the drawings, but also comprises any modifications or equivalents within the scope of the invention.