Abstract:
A scaled head frame positioner and tabletop adapter are provided. The positioner may be employed for any neurosurgical procedure that requires fixed positioning of the stereotactic head frame or ring onto a patient&#39;s skull. The positioner employs a generally triangular shaped member with Velcro tapes fixed at each corner. The tapes have measurement markings, such as measurement tapes. The positioner supports the head frame with the tapes engaging means on the frame and fastened back to themselves, with markings indicating distances to adjust the position of the frame about the patient&#39;s head. Furthermore, the tabletop adapter clamps the patient with a stereotactic head frame onto a CT or treatment table. The tabletop adapter includes a generally U-shaped bracket secured to a support to be placed on the tabletop. The bracket is attachable to the head frame of the patient to hold his head in a desired position.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present disclosure relates generally to stereotactic framework systems, and more particularly, to a scaled head frame positioner for positioning of a stereotactic frame head ring onto a patient&#39;s skull and tabletop adapter to clamp the patient with the stereotactic frame head ring onto a CT or treatment table. 
         [0003]    2. Description of the Related Art 
         [0004]    Procedures which involve surgery, radiation or other procedures performed on the brain or other intracranial structures are especially hazardous for the patient, because of the extreme sensitivity of brain tissues, the difficulty in identifying and accessing the particular portion of the brain upon which a procedure is to be performed, and the danger of damaging brain tissues which overlie or surround the portion upon which the procedure is to be performed. The desire for precisely locating and accessing interior portions of the brain and other intracranial structures have lead to the development of the neurosurgical subspecialty of stereotactic surgery or “stereotaxis.” 
         [0005]    Stereotaxis ordinarily involves the use of an external apparatus attached to the patient&#39;s skull during presurgical diagnostic procedures and during surgical procedures. The apparatus provides a grid or framework in fixed position relative to the patient&#39;s skull which may be used to establish a coordinate system for locating, in a reproducible manner, the precise position of a lesion or other area within the intracranial area. The fixed framework also provides a structure external to the skull to which measuring devices, surgical instruments and the like can be attached and, by appropriate manipulation, positioned so they can be introduced to exact points within the intracranial structure. Surgical or other procedures then can be performed at an exact, predetermined, point within the brain or other tissue. The object of such devices is, ultimately, to permit safe impact at a predetermined location within the intracranial space for purposes such as excision, surgical biopsy, placement of catheters, installation of devices, removal of cysts, tumors or hematomas, or may involve focusing or direction of laser beams, radiation, magnetism or the like for diagnostic or treatment purposes. 
         [0006]    The development of CAT scan technology, magnetic resonance imaging (MRI), angiography, digital subtraction angiography (DSA) and similar diagnostic procedures for producing images of structures contained within tissue has been applied to the field of stereotaxis to produce image-directed stereotaxis. A stereotactic apparatus is used in conjunction with advanced diagnostic imaging procedures to produce internal tissue images keyed to a cartesian or polar coordinate system. When the same stereotactic apparatus is utilized during surgery, it is possible to access a precise position inside the brain identified on the diagnostic images on the basis of the same coordinate system. For example, in stereotactic radiosurgery, consisting of a large dose of single fraction irradiation of a small intracranial target with radiation, a head ring of a stereotactic apparatus is positioned on the patient&#39;s head to ensure precise immobilization of the patient&#39;s head for imaging study and treatment. 
         [0007]    Therefore, a need exists for techniques for easily and precisely positioning a head ring or frame of a stereotactic framework system to a patient&#39;s head so that the head ring or frame can be applied precisely in an exact position relative to the patient&#39;s head. 
       SUMMARY 
       [0008]    A scaled head frame positioner and tabletop adapter are provided. The positioner of the present disclosure may be employed for any neurosurgical procedure that requires fixed positioning of the stereotactic head frame onto the patient&#39;s skull. The positioner employs a generally triangular shaped member with Velcro tapes fixed at each corner. The tapes have measurement markings, such as measurement tapes. The positioner supports the head frame with the tapes engaging means on the frame and fastened back to themselves, with markings indicating distances to adjust the position of the frame about the patient&#39;s head. Furthermore, the present disclosure provides for a tabletop adapter to clamp the patient with a stereotactic head frame onto a CT or treatment table. Unlike the prior art which uses plastic blocks to support the patient&#39;s head with the stereotactic head frame, the tabletop adapter includes a generally U-shaped bracket secured to a support to be placed on the tabletop. The bracket is attachable to the head frame of the patient to hold his head in a desired position. 
         [0009]    According to one aspect of the present disclosure, an apparatus for easily and precisely fixing a frame head ring to a patient&#39;s head is provided, the apparatus including a rigid ring configured to have substantially the same diameter as the frame head ring, the rigid ring having a top surface and a bottom surface; a plurality of connectors disposed on and projecting from the bottom surface of the rigid ring, the plurality of connectors being adapted to coupled the rigid ring to the frame head ring; a support member for supporting the rigid ring upon the patient&#39;s head, the support member being adapted to come into contact with a top of the patient&#39;s head; and at least three adjustment members for coupling the rigid ring to the support member, the at least three adjustment members having scaled indicia for precisely adjusting the frame head ring relative to the patient&#39;s head. 
         [0010]    According to another aspect of the present disclosure, an adapter for fixing a stereotactic frame head ring onto a CT or treatment table is provided, the adapter includes a generally, flat rectangular substrate configured to be disposed on a CT or treatment table and to support the patient on the CT or treatment table, the substrate having a top surface and a bottom surface; at least two connectors disposed on and projecting from the bottom surface of the substrate, the at least two connectors being adapted to coupled the substrate to the CT or treatment table; and a bracket disposed on one end of the substrate having at least two receiving members projecting perpendicular from the top surface of the substrate, the at least two receiving members configured for receiving screws of the head ring for fixing the head ring relative to the CT or treatment table. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which: 
           [0012]      FIG. 1  is a perspective view of a positioner for positioning of a stereotactic head frame onto a patient&#39;s skull in accordance with the present disclosure; 
           [0013]      FIG. 2  is a detailed view of a connector of the positioner shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a bottom perspective view of the positioner shown in  FIG. 1 ; 
           [0015]      FIG. 4  illustrates a positioner of the present disclosure being coupled to a stereotactic head ring; 
           [0016]      FIG. 5  illustrates the positioner and head ring coupled to a patient&#39;s skull; 
           [0017]      FIG. 6  is a perspective view of a radiation machine and head frame tabletop adapter in accordance with an embodiment of the present disclosure; 
           [0018]      FIG. 7  is an end view of the tabletop adapter shown in  FIG. 6 ; 
           [0019]      FIG. 8  is a bottom view of the tabletop adapter shown in  FIG. 6 ; 
           [0020]      FIG. 9  illustrates the head ring and localizer about to be coupled to the tabletop adapter; and 
           [0021]      FIG. 10  illustrates the head ring fixed to the tabletop adapter. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Preferred embodiments of the present disclosure will be described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. 
         [0023]    A scaled head frame positioner  10  in accordance with the present disclosure is generally shown in  FIGS. 1-5 . The positioner  10  of the present disclosure will help a user, e.g., a neurosurgeon, to stabilize a stereotactic head frame and to optimize the position of the head frame so that the neurosurgeon can fix the head frame onto the patient&#39;s skull with precision and ease. The positioner  10  further provides quantitative indications for adjustment via scaled tapes or straps so the head frame can be applied precisely in an exact position relative to the patient&#39;s head. 
         [0024]    The positioner  10  includes a rigid ring  12  configured to have substantially the same diameter as the frame head ring  14 . The rigid ring  12  is generally flat and includes a top surface  16  and a bottom surface  18 . A plurality of connectors  20  are disposed on and projecting from the bottom surface  18  of the rigid ring  12 . The plurality of connectors  20  are adapted to coupled the rigid ring  12  to the frame head ring  14  as will be described in more detail in relation to  FIG. 4 . Each connector  20  includes a ball portion  22  and a stem portion  24 . 
         [0025]    A support member  26  for supporting the rigid ring upon the patient&#39;s head is provided. The support member  26  is configured to come into contact with a top of the patient&#39;s head. At least three adjustment members  28  are provided for coupling the rigid ring  12  to the support member  26 . The at least three adjustment members  28  have scaled indicia for reproducibly and/or precisely adjusting the frame head ring relative to the patient&#39;s head. In one embodiment, each of the adjustment members  28  will include a loop and hook type fastener, e.g., Velcro, on one surface of the adjustment member so the adjustment member  28  may be threaded through bracket  30  of the rigid ring  12  and fasten back upon itself to secure the support member  26  to the ring  12 . The adjustment members  28  can take on other forms such as a strap and buckle and the like. 
         [0026]    The adjustment members  28  will include on one surface scaled indicia  31 . By having scaled indicia on the adjustment members  28  a user can determine settings for a particular patient and make precise adjustments to each adjustment member  28  to precisely position the head ring  12 , e.g., to avoid certain features of the patient&#39;s head, to rotate the head ring properly, etc. It is to be appreciated that the adjustment members  28  may have one or more measurement system disposed on one surface. For example, on one side of the surface of the adjustment member  28  may display an inch scale  32  while the other side may display a centimeter scale  34 . Other measurement scales and systems are contemplated. 
         [0027]    In the embodiment shown, the support member  26  is generally triangular but other configurations are contemplated. In this embodiment, the support member  26  has three corners  36  with the adjustment members  28  fixed at each of the corners  36 . In this manner, the weight of the head ring  14  is equally distributed and is stable on the patient&#39;s head. Other shapes for the support member  26  are contemplated by the present disclosure as along as the adjustment members  28  are equally spaced about the periphery of the support member  26  for stability. 
         [0028]    In use, the positioner  10  will be coupled to a head ring  14  and the positioner  10  and head ring  14  will be disposed on the patient&#39;s head to fix the head ring to the patient&#39;s skull. 
         [0029]    Referring now to  FIG. 4 , there is shown a BRW/CRW-type stereotactic head ring  14  as is known in the art. The head ring  14  comprises an annular base  38 , formed of metal. Four vertical brackets  40  extend upward from the inside diameter of the base  38 . Four adjustable pins  42  are threadedly engaged with the upper portions of the brackets  40 . The pins  42 , when rotated relative to the brackets  40 , extend inwardly to engage the patient&#39;s skull, or retract outwardly to disengage from the patient&#39;s skull. The pins  42  have pointed tips or ends  44  which, when the pins are extended inwardly, penetrate the outer tissue of the patient&#39;s head and engage the bone of the skull so as to rigidly and invasively affix the head ring  14  to the skull. The pin tips or ends  44  may be removable and replaceable so as to reduce the possibility of spreading infection from one user of the head ring apparatus to the next. If reusable, the pins tips or ends  44  are sterilized after each patient&#39;s use. 
         [0030]    The head ring  14  includes means for attaching to it other appliances used in stereotactic procedures, e.g., a localizer. As shown, these comprise a plurality, ordinarily three, of recessed ball sockets  46  into which the ball-type connectors of compatible stereotactic appliances may be received. As shown in  FIG. 4 , the connectors  20  of positioner  10  align with (as indicated by the arrows) and are received by the sockets  46  to fix the positioner to the head ring  14 . Spindles  48  extending downwardly from the underside of the head ring  14  are connected to internal means (not shown) in the head ring base  38  for locking in place ball-type connectors  20  received in the sockets  46 . 
         [0031]    Referring to  FIG. 5 , the positioner  10  and head ring  14  are disposed on a patient&#39;s head  50 . Initially, the support member  26  of the positioner  10  comes into contact with a top potion of the patient&#39;s head  50  and generally supports the head ring  14  about the patient&#39;s head in a stable manner. The user, e.g., neurosurgeon, can then adjust the position of the head ring  14  and corresponding pin tips or ends  44  relative to the patient&#39;s head by adjusting the adjustment members  28 . For example, when the adjustment members  28  include hook and loop fasteners, the user can separate an end  52  that has passed through the bracket  30  from the remaining portion  54 , adjust the adjustment member  28  accordingly and then reposition the end  52  back onto the other portion  54  of the adjustment member  28 . Once the head ring  14  has been set, the pins  42  are adjusted to fix the head ring  14  to the patient&#39;s head  50 . 
         [0032]    The position of the positioner can then be determined by reading the indicia  31  on the adjustment members  28 . It is to be appreciated that each of the adjustment members may be adjusted to a different position and thus have a different measurement reading. Once the user is satisfied with the placement of the head ring  14 , the positioner  10  can be removed from the head ring  14  by loosening the spindles  48  of the head ring  14 . It is to be further appreciated that the positioner  10  of the present disclosure holds the head ring  14  in a steady manner during the positioning process enabling the neurosurgeon to adjust the head ring  14  easily and precisely in any direction. 
         [0033]    The stereotactic head ring  14  may be employed to support a localizing device used for establishing a coordinate system and measurement reference for diagnostic procedures and radiation treatment setup. An exemplary localizing device is described in U.S. Pat. No. 5,628,315, the contents of which are incorporated by reference. When diagnostic scanning procedures such as magnetic resonance imagining (“MRI”) or computerized axial tomography (“CAT scan”) or the like are performed on a patient&#39;s head with the localizing device in place, the localizing device provides fixed indicia (fiducials) against which measurements can be made and relative to which a coordinate system can be established for the cranium and intracranial areas. In conjunction with existing computer software developed for the system, the diagnostic images produced from the CAT scan, MRI, etc., performed with the localizing device in place will provide X, Y and Z coordinates (or, in some applications, polar coordinates) for any portion of the patient&#39;s skull, brain or other tissue within the cranium which is to be investigated or treated. Such systems make it possible, for example, to identify the location of a tumor, or the like, within the patient&#39;s brain by X, Y and Z coordinates which define the position of the tumor, as well as its points of greatest extension within the brain tissue, etc. Since the localizing device is rigidly attached to the head ring  14 , which in turn is rigidly attached to the patient&#39;s skull  50 , the coordinates of diagnostic measurements made utilizing the localizing device may be used directly as coordinates for later surgical, or other treatment, procedures performed utilizing other appliances or instruments rigidly attached to the head ring  14  as long as the head ring remains attached in position to the patient&#39;s head. 
         [0034]    Once the head ring has been secured to the patient, a localizer is then secured to the head ring before a patient is placed in the diagnostic or radiation machine. An exemplary radiation machine is described in U.S. Patent Application Publication No. U.S. 2007/0032795, the contents of which are hereby incorporated by reference. FIG. 1 from U.S. 2007/0032795 has been reproduced here as  FIG. 6 . Referring now to the drawings,  FIG. 6  illustrates a radiation therapy machine  60  suitable for use with the present invention. The radiation therapy machine  60  preferably includes a radiotranslucent couch or treatment table  62  having a cantilevered top  64 . The couch top  62  is received within a bore  66  of an annular housing  68  of the radiation therapy machine  60  with movement of the couch  62  along tracks  70  extending along a longitudinal axis translation. The couch  62  is preferably disposed along the longitudinal axis and may slide along that axis through the bore  66  passing first the front surface and then the rear surface. The couch  62  is supported along guide tracks  70  and moved by a motorized drive, such as is well known in the art, so that its position may be controlled by a computer  72 . A rotating gantry, coaxial with the bore  66  and positioned within the housing  68 , supports an x-ray source and a high energy radiation source on its inner surface. 
         [0035]    Conventionally, a plastic block or blocks have been used to support the patient&#39;s head with the stereotactic head frame on the couch or treatment table  62 . However, the blocks allow the patient&#39;s head to move and thus the head frame which may cause misalignment with the coordinate systems. Furthermore, the conventional configuration with the blocks puts a great deal of pressure on for example a plastic CT localizer box. The plastic CT localizer box acts as a weight support for the patient&#39;s head. It is foreseeable that repeated pressure on the plastic CT localizer box will ultimately compromise the CT localizer box&#39;s integrity. To overcome these deficiencies, a tabletop adapter  74  is provided to fix the head ring on the patient&#39;s head to the CT or treatment table  62  which will prevent movement by the patient and relieve unnecessary pressure on the localizing device. 
         [0036]    Referring to  FIGS. 6-10 , the adapter  74  includes a generally, flat rectangular substrate  76  configured to be disposed on a treatment table  62  and to support the patient on the treatment table  62 . The substrate  76  has a top surface  78  and a bottom surface  80 . At least two connectors  82  are disposed on and project from the bottom surface  80  of the substrate  76 . The at least two connectors  82  are adapted to couple the substrate  76  to recesses  84  formed along the sides of the treatment table  62 . The adapter  76  further includes a U-shaped bracket  86  disposed on one end of the substrate  76  having at least two receiving members  88 ,  90  projecting perpendicular from the top surface  78  of the substrate  76 . The at least two receiving members  88 ,  90 , e.g., semi-circular apertures, are configured for receiving screws of the head frame  14  for fixing the head frame  14  relative to the treatment table  62 , as shown in  FIGS. 9 and 10 . 
         [0037]    Referring to  FIGS. 9 and 10 , the adapter  76  has been fixed to the treatment table  62  by coupling the connectors  82  into the recesses  84  of the table  62 . For clarity, the head ring  14  with localizing device  94  is shown without being fixed to a patient&#39;s head. The two conical T-bolt screws  92  are aligned with the receiving members  88 ,  90  of the bracket  86 . Once the screws  92  are fully received by the receiving members  88 ,  90 , the screws  92  are clamped down and the head ring  14  is fixed to the adapter  76 , and in turn, the head ring  14  is fixed to the treatment couch or table  62 . By securing the head ring to the treatment table  62  in this manner, the adapter  76  eliminates any potential patient head movement during treatment, e.g., a CT simulation or radiotherapy treatment. Furthermore, the adapter  76  reduces any additional pressure on the localizing device. 
         [0038]    Once the patient is set on the couch or table  62 , the patient can be positioned into the bore  66  of the radiation machine  60 . 
         [0039]    While the disclosure has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.