TECHNICAL FIELD  
       [0001]     The present invention relates to surgical navigation, and more particularly to surgical navigation systems that combine multiple sources of information to aid in localization.  
       BACKGROUND  
       [0002]     Recent advances in minimally invasive surgery utilize anatomical data collected by preoperative scanning techniques, for example magnetic resonance imaging (MRI), computerized tomography (CT), ultrasound, fluoroscopy and positron emission tomography (PET), to facilitate guidance of an interventional device to a precise location by providing a more accurate view of an anatomical context through which the device is navigated. To accomplish this, the anatomical data must be registered with position-indicating data, i.e. that data collected during the intervention, which reflects positions of an interventional tool; some registration methods have been described in U.S. Pat. Nos. 6,235,038 and 6,402,762, which are incorporated by reference herein. Furthermore, U.S. Patent Application 2003/0187358, which is also incorporated by reference herein, describes registration of 3D image data within an interventional system using three anatomical landmarks.  
         [0003]     While surgical navigation using registered images is useful, it may not be necessary in all interventional procedures. Simple imaging performed at the time of the intervention without the need for registration of data from multiple sources, or no imaging at all, may be sufficient for some interventional procedures. However, systems and/or software needed to carry out the registration may be integrated components of standard navigational equipment used for all interventional procedures whether or not the registration function is required. For this and other reasons, it would be desirable to incorporate into such equipment means for monitoring use of the registration function.  
       SUMMARY  
       [0004]     Methods according to embodiments of the present invention comprise the following steps: receiving authorization to use registration capabilities included in a navigation system and registering one or more anatomical data sets stored in the navigation system with one or more position-indicating data sets collected by an interventional system, upon receipt of authorization. Methods according to additional embodiments comprise the step(s) of counting a number of times registration of data sets occurs during an interventional procedure and/or communicating the registration(s) to a billing system.  
         [0005]     Systems and configurations according to embodiments of the present invention comprise an authorization tag/device adapted to send a signal to a registration sub-system of the system, which signal enables or disables registration of one or more anatomical data sets with one or more position-indicating data sets. Systems and configurations according to alternate embodiments of the present invention comprise a communications sub-system establishing a communication link between the system and an online authorization system, which sends a signal to either enable or disable a registration sub-system of the system. Systems and configurations according to additional embodiments of the present invention comprise a counter adapted to count a number of times a registration function is used and/or a communications sub-system adapted to communicate the registration(s) to a billing system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a flow chart describing methods according to alternate embodiments of the present invention.  
         [0007]      FIG. 2  is a block diagram of a surgical system  15  according to an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0008]     The following description is illustrative of particular embodiments of the invention and therefore does not limit its scope, but is presented to assist in providing a proper understanding of the invention. The figures are intended for use in conjunction with the explanations in the following detailed description.  
         [0009]      FIG. 1  is a flow chart describing methods according to alternate embodiments of the present invention.  FIG. 1  illustrates a first step  100  wherein an interventional procedure is begun; a purpose for such a procedure may be, for example, to implant a therapeutic or diagnostic device, to perform a therapeutic or diagnostic procedure, to gather data sets of navigational landmarks or any combination thereof, and a variety interventional systems and processes associated with each of these purposes are well known to those skilled in the art. Approximately coincident with first step  100  an authorization step  110  takes place in which a navigational system, used in conjunction with the interventional system, receives a signal directing the navigational system to register or not to register one or more anatomical data sets with another one or more position indicating data sets collected during the interventional procedure. The one or more anatomical data sets, according to one embodiment of the present invention, include 3-dimensional anatomical data collected by a scan; examples of such scans include, but are not limited to, MRI, CT, ultrasound, fluoro and PET. Examples of the one or more data sets gathered during the interventional procedure include but are not limited to electrical maps, pressure maps, fluoroscopic images and ultrasound images.  
         [0010]     According to one embodiment of the present invention, the authorization signal of step  110  is sent by a tag or device included with the interventional system; according to an alternate embodiment the signal is sent by an online authorization system. Means for sending the authorization signal will be described in greater detail in conjunction with  FIG. 2 .  
         [0011]     If, in authorization step  110 , the navigational system receives a signal directing the system to register, a step  130  follows in which the one or more anatomical data sets are registered to the interventional system, that is, the anatomical data is combined with one or more position indicating data sets collected by the interventional system to provide a registered image, step  140 ; registration methods are known to those skilled in the art and examples of these methods are described in the aforementioned patents and patent application incorporated by reference herein. If the navigation system receives a signal directing the system not to register, the registration function is bypassed and the system simply provides an image or images based upon the one or more data sets collected by the interventional system without registration, step  120 .  
         [0012]      FIG. 1  further illustrates, approximately coincident with registration step  130 , a counting step  150 . Under step  150 , counts relating to a number of times the registration step occurs in order to monitor the use of the registration function are made. Because a number of different images may be required to assist navigation during the interventional procedure, a number of different registrations may be required to generate multiple registered images. According to the illustrated embodiment, an accounting step  160  receives the count in order to automatically generate a bill for use of the registration function. According to another embodiment, counting step  150  is not included and, alternatively, accounting step  160  flows from registration step  130 , i.e. per the dashed line.  
         [0013]     It should be noted that embodiments of the present invention include methods, which do not include all of the steps illustrated in  FIG. 1 . For example, one method according to the present invention includes only steps  100 ,  110 ,  120 ,  130  and  140  (i.e. including an authorization function but not including counting or billing), while another method includes only steps  100 ,  130 ,  140 ,  150  and  160  (i.e. including counting and billing functions but not including authorization).  
         [0014]      FIG. 2  is a block diagram of a surgical system  15  according to an embodiment of the present invention.  FIG. 2  illustrates system  15  including a navigational system  10 , an interventional system  20 , a billing system  50  and an online authorization system  80 . According to embodiments of the present invention interventional system  20  may be any one of those known to a person skilled in the art, as previously described in conjunction with  FIG. 1 ; examples of interventional systems include but are not limited to those including implantable leads or catheters having means to collect position-indicating data during the interventional procedure, for example electrodes and/or transducers.  FIG. 2  further illustrates navigational system  10  including an anatomical data storage subsystem  21 , a position-indicating data storage subsystem  22 , a registration subsystem  45 , and a recognition device  40 , which receives a signal from an authorization tag/device  25 , included with interventional system  20 . According to embodiments of the present invention, the signal either enables or disables registration sub-system  45 . In the event registration sub-system  45  is enabled, one or more data sets from anatomical data storage  21  will be combined with one or more data sets from position-indicating data storage  22  within registration subsystem  45 , which is adapted to register the data sets and prepare a registered image for an image display monitor  30 . Sources of anatomical data were previously described in conjunction with  FIG. 1 . If registration sub-system  45  is disabled, image display monitor  30  receives an un-registered image including data from storage  22 .  
         [0015]     Authorization tag/device  25 , according to some embodiments of the present invention, is included in a package with one or more components of interventional system  20  and may either be an independent element or an element affixed to one of the components of system  20 . According to one embodiment, tag/device  25  is passive such that only its presence in proximity to navigational system is detected by recognition device  40  and this detection enables registration sub-system  45 ; examples of such tags include but are not limited to a resonant coil and a radio frequency identification (RFID) tag, either of which may be integrated into an implantable pulse generator, a lead or a catheter according to means known to those skilled in the art. Alternatively, tag/device  25  may be programmed to send a signal, for example a passive bar code or an active transponder, to either enable or disable registration sub-system  45  via recognition device  40 . According to alternate embodiments tag/device  25  need not be packaged with any components of interventional system  20  and may be associated with other components used in interventional procedures, such as surgical drapes or an adhesive patch.  
         [0016]      FIG. 2  further illustrates navigational system  10  including a communications sub-system  70 , which can be any form of electronic communication, such as telephone, internet, local network, wireless or the like, linked to registration sub-system  45 ; according to another embodiment of the present invention, when use of registration sub-system  45  is requested, communications sub-system  70  sends the request to an online authorization system  80 , which, rather than tag/device  25 , sends an enabling or disabling signal back to communications sub-system  70 , which in turn passes the signal to registration sub-system  45 . Online authorization system  80  may be anything ranging from a fully automated system to a connection to a person who authorizes the use.  
         [0017]     According to another aspect of the present invention, communications sub-system  70  delivers information regarding use of registration sub-system  45  to billing system  50 , which uses the information to accrue charges related to use of registration sub-system  45 . According to an alternate embodiment, billing system  50  receives information regarding authorization for use of registration sub-system  45  when tag/device  25  is pulled from inventory for-an interventional procedure, thereby accruing a charge related to use of registration sub-system  45 .  
         [0018]      FIG. 2  further illustrates navigational system  15  including a counter  60  adapted to count a number of times registration sub-system  45  is used in order to monitor use of the registration function; a count provided by counter  60  may be sent via communications sub-system  70  to billing system  50 . According to some embodiments, counter  60  includes additional capability to time-stamp each use of registration sub-system  45  and to record information regarding which data sets are registered for each count.  
         [0019]     In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention.
A surgical intervention data base includes major systems including a navigational system, an interventional system, a billing system and an on-line authorization system. The navigational system includes sub-systems that provide communication between the major systems to enable registration of data sets, image displays and billing capabilities for services rendered. Further, the navigational system distinguishes between registered and non-registered images.