Patent Publication Number: US-2016223753-A1

Title: Launch fixture for optical shape sensing

Description:
BACKGROUND 
     1. Technical Field 
     This disclosure relates to medical instruments and more particularly to shape sensing optical fibers in medical applications. 
     2. Description of the Related Art 
     Optical shape sensing (OSS) is a technology that permits accurate three-dimensional (3D) reconstruction of a shape of a fiber along its entire length. Integrating the fiber into an OSS enabled instrument requires coupling the fiber to the instrument such that any movement of the device can be reconstructed with respect to a fixed frame of reference. Having a fixed or static launch region is needed since the fixed region provides a search template for a reconstruction algorithm to perform correlation and to match a reference to sample data. The reconstruction initializes after this fixed region. The fixed region also defines the frame of reference (0,0,0) for OSS and, in essence, the coordinate system in the shape sensing space. 
     SUMMARY 
     In accordance with the present principles, a launch fixture for optical shape sensing (OSS) includes a first fixation device configured to receive and secure an optical fiber. A fiber storage area is configured to receive and maintain the optical fiber within specified dimensions. A second fixation device is configured to receive and secure a flexible OSS enabled instrument. A launch region is configured to receive and maintain the optical fiber in a known geometric configuration before entering the second fixation device. A feature is provided for aligning and coupling to a launch fixture base, which is configured to secure the launch fixture. 
     An optical shape sensing (OSS) system includes a launch fixture base configured to be connected to a support structure, and a launch fixture configured to be secured on the launch fixture base by at least one feature for aligning and coupling the launch fixture base to the launch fixture. The launch fixture includes a first fixation device configured to receive and secure an optical fiber; a fiber storage area configured to receive and maintain the optical fiber within specified dimensions; a second fixation device configured to receive and secure a flexible OSS enabled instrument; and a launch region configured to receive and maintain the optical fiber in a known geometric configuration before entering the second fixation device. 
     A method for optical shape sensing (OSS) includes providing ( 502 ) a launch fixture having a first fixation device configured to receive and secure an optical fiber, a fiber storage area configured to receive and maintain the optical fiber within specified dimensions, a second fixation device configured to receive and secure a flexible OSS enabled instrument, a launch region configured to receive and maintain the optical fiber in a known geometric configuration before entering the second fixation device, and at least one feature for aligning and coupling to a launch fixture base, which is configured to secure the launch fixture; and sensing a shape of the optical fiber. 
     These and other objects, features and advantages of the present disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       This disclosure will present in detail the following description of preferred embodiments with reference to the following figures wherein: 
         FIG. 1  is a block/flow diagram showing a shape sensing system which employs a launch fixture with controlled fiber positioning in accordance with one embodiment; 
         FIG. 2  is a perspective view of a launch fixture with controlled fiber positioning in accordance with one embodiment; 
         FIG. 3  is a perspective view of a launch fixture base configured to secure one or more launch fixtures in accordance with one embodiment; 
         FIG. 4  is a perspective view showing a plurality of stacked launch fixtures with controlled fiber positioning in accordance with one embodiment; 
         FIG. 5  is a side view of a launch fixture base rack for storing a plurality of launch fixtures in accordance with one embodiment; 
         FIG. 6  is a perspective view of a launch fixture for handling a plurality of shape sensing devices with controlled fiber positioning in accordance with another embodiment; 
         FIG. 7  is a perspective view of a modular launch fixture with attachable/detachable modules in accordance with one embodiment; 
         FIG. 8A  is a side view showing a sterile boundary between a launch fixture and a launch fixture base in accordance with one embodiment; 
         FIG. 8B  is a top view showing an open launch fixture with a partitioned sterile boundary between distal and proximal portions of the launch fixture in accordance with one embodiment; 
         FIG. 9  is a top view of a rail for conveying a launch fixture base in accordance with one embodiment; and 
         FIG. 10  is a flow diagram showing a method for optical shape sensing in accordance with an illustrative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     In accordance with the present principles, a launch fixture and launch fixture base design provide for rapid attachment and detachment of one or more optical shape sensing (OSS) enabled flexible instrument(s) to a fixed reference in an operating theatre. The fixture can also be disposed in a transition zone between sterile and non-sterile regions in an operating theatre, allowing for the rapid exchange of OS S-enabled devices by personnel in the non-sterile region without breaking the sterile barrier. 
     In one embodiment, the launch fixture ensures that the geometric relationship between adjacent instrument frames of reference and the launch fixture base frame of reference are known, so that each instrument is automatically registered to the launch fixture base once connected. Given that the launch fixture base is registered to a patient or imaging frame of reference prior to a beginning of the procedure, this architecture permits each instrument to be rapidly deployed in a co-registered frame of reference. In addition, the overall footprint of the instruments in the operating theatre can be minimized through the use of vertical, horizontal, or angled stacking. 
     During clinical use, it is likely that multiple shape sensing enabled instruments will be deployed and exchanged during a given procedure. In one system architecture, each instrument could be attached to the operating table using a unique launch fixture base. However, as the number of instruments employed increases, a number of components attached to the table would increase accordingly. This would hinder clinician movement around the table and result in a cluttered operating field. In addition, since the OSS fiber within each instrument will reconstruct the shape of the instrument with respect to a frame of reference located within that instruments&#39; launch fixture, each instrument would need to be individually registered to the patient/imaging system frame of reference. 
     In accordance with the present principles, the footprint of the instrument launch fixtures within the operating theatre is minimized, as well as the time spent registering devices. The launch fixture and launch fixture base permit rapid exchange of devices while maintaining a defined geometric relationship between frames of reference so that re-registration is not required. This fixed frame of reference is included within a launch fixture, which is coupled to a proximal end of the flexible instrument and includes design features which allow the fiber to be safely and securely coupled to the instrument. By attaching this launch fixture rigidly to the launch fixture base, which may itself be rigidly connected to the operating table, needed transformations between an instrument frame of reference and patient/imaging frames of reference can be computed. Thus, the reconstructed shape of the instrument can be overlaid on pre- and intra-operative images and used for navigation purposes. 
     It should be understood that the present invention will be described in terms of medical instruments; however, the teachings of the present invention are much broader and are applicable to any fiber optic shape sensed instruments. In some embodiments, the present principles are employed in tracking or analyzing complex biological or mechanical systems. In particular, the present principles are applicable to internal tracking procedures of biological systems, procedures in all areas of the body such as the lungs, gastro-intestinal tract, excretory organs, blood vessels, etc. The elements depicted in the FIGS. may be implemented in various combinations of hardware and software and provide functions which may be combined in a single element or multiple elements. 
     The functions of the various elements shown in the FIGS. can be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions can be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which can be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and can implicitly include, without limitation, digital signal processor (“DSP”) hardware, read-only memory (“ROM”) for storing software, random access memory (“RAM”), non-volatile storage, etc. 
     Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Thus, for example, it will be appreciated by those skilled in the art that the block diagrams presented herein represent conceptual views of illustrative system components and/or circuitry embodying the principles of the invention. Similarly, it will be appreciated that any flow charts, flow diagrams and the like represent various processes which may be substantially represented in computer readable storage media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown. 
     Furthermore, embodiments of the present invention can take the form of a computer program product accessible from a computer-usable or computer-readable storage medium providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer readable storage medium can be any apparatus that may include, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W), Blu-Ray™ and DVD. 
     Referring now to the drawings in which like numerals represent the same or similar elements and initially to  FIG. 1 , a system  100  for optical shape sensing is illustratively shown in accordance with present embodiments. System  100  may include a workstation or console  112  from which a procedure is supervised and/or managed. Workstation  112  preferably includes one or more processors  114  and memory  116  for storing programs and applications. Memory  116  may store an optical sensing module  115  configured to interpret optical feedback signals from a shape sensing device or system  104 . Optical sensing module  115  is configured to use the optical signal feedback (and any other feedback, e.g., electromagnetic (EM) tracking) to reconstruct deformations, deflections and other changes associated with a medical device or instrument  102  and/or its surrounding region. The medical device  102  may include a catheter, a guidewire, a probe, an endoscope, a robot, an electrode, a filter device, a balloon device, or other medical component, etc. 
     The shape sensing system  104  on device  102  includes one or more optical fibers  126  which are coupled to the device  102  in a set pattern or patterns. The optical fibers  126  connect to the workstation  112  through cabling  127 . The cabling  127  may include fiber optics, electrical connections, other instrumentation, etc., as needed. 
     Shape sensing system  104  with fiber optics may be based on fiber optic Bragg grating sensors. A fiber optic Bragg grating (FBG) is a short segment of optical fiber that reflects particular wavelengths of light and transmits all others. This is achieved by adding a periodic variation of the refractive index in the fiber core, which generates a wavelength-specific dielectric mirror. A fiber Bragg grating can therefore be used as an inline optical filter to block certain wavelengths, or as a wavelength-specific reflector. 
     A fundamental principle behind the operation of a fiber Bragg grating is Fresnel reflection at each of the interfaces where the refractive index is changing. For some wavelengths, the reflected light of the various periods is in phase so that constructive interference exists for reflection and, consequently, destructive interference for transmission. The Bragg wavelength is sensitive to strain as well as to temperature. This means that Bragg gratings can be used as sensing elements in fiber optical sensors. In an FBG sensor, the measurand (e.g., strain) causes a shift in the Bragg wavelength. 
     One advantage of this technique is that various sensor elements can be distributed over the length of a fiber. Incorporating three or more cores with various sensors (gauges) along the length of a fiber that is embedded in a structure permits a three dimensional form of such a structure to be precisely determined, typically with better than 1 mm accuracy. Along the length of the fiber, at various positions, a multitude of FBG sensors can be located (e.g., 3 or more fiber sensing cores). From the strain measurement of each FBG, the curvature of the structure can be inferred at that position. From the multitude of measured positions, the total three-dimensional form is determined. 
     As an alternative to fiber-optic Bragg gratings, the inherent backscatter in conventional optical fiber can be exploited. One such approach is to use Rayleigh scatter in standard single-mode communications fiber. Rayleigh scatter occurs as a result of random fluctuations of the index of refraction in the fiber core. These random fluctuations can be modeled as a Bragg grating with a random variation of amplitude and phase along the grating length. By using this effect in three or more cores running within a single length of multi-core fiber, the 3D shape and dynamics of the surface of interest can be followed. 
     In one embodiment, workstation  112  includes an image generation module  148  configured to receive feedback from the shape sensing device  104  and display position/shape for the shape sensing device  104  within a volume  131 . An image  134  of the shape sensing device  104  within the space or volume  131  can be displayed on a display device  118 . Workstation  112  includes the display  118  for viewing internal images of a subject (patient) or volume  131  and may include the image  134  as an overlay or other rendering of shapes of the shape sensing device  104 . Display  118  may also permit a user to interact with the workstation  112  and its components and functions, or any other element within the system  100 . This is further facilitated by an interface  120  which may include a keyboard, mouse, a joystick, a haptic device, or any other peripheral or control to permit user feedback from and interaction with the workstation  112 . 
     A launch fixture  150  includes mechanical features  152  configured to ensure that the fiber  126  or the shape sensing device  104  can be coupled to the elongate instrument  102  such that the fiber measures changes in shape of the instrument with respect to a fixed frame of reference. Each OSS enabled instrument  102  employs a launch fixture ( 150 ) to define a fixed frame of reference which may be registered to a patient frame of reference  136 , or imaging frame of reference  138 , or both. 
     A launch fixture base  160  is rigidly attached to a fixed feature or support structure  162  in the operating theatre (e.g., an operating table or similar structure) which allows for multiple launch fixtures  150  (and hence multiple OSS enabled instruments  102 ) to be attached and co-registered to the patient frame of reference  136 , or imaging frame of reference  138 , or both. In another embodiment, there is more than one OSS enabled instrument  104  within a single fixture  150 . The launch and coordinate systems of these fibers are known with respect to each other as well as the patient and imaging frames of reference  136 ,  138 , thus allowing faster use when these devices are used in conjunction, such as, e.g., a guidewire and a catheter being used together. 
     In another embodiment, the launch base  160  and/or the launch fixture  150  may include features to monitor the use of the launch fixture  150  and devices  102 . For example, a scan mechanism  135  may be incorporated into the base  160  or fixture  150  (e.g., a radiofrequency scanner) that automatically detects which OSS enabled instrument  102  is being used. Mechanism  135  may monitor a number of times a same device is clipped in (to monitor or prevent) more than one-time use of the device  102 . The mechanism  135  may include an indicator (e.g., a light, counter or color strip) that indicates an end of life (after say  1000  devices have been mounted) of the launch base  150  and alert the service engineer for maintenance. Other configurations for mechanism  135  are also contemplated. 
     In one embodiment, a position of the launch fixture base  160  (and/or launch fixture  150 ) with respect to an imaging system  110  is tracked using an appropriate sensor  137  (position encoder, magnetic tracking, etc.). This provides easy registration to the imaging system  110 . 
     Another feature of the launch fixture  150  is that it may lay in a zone separating a sterile region  152  (inside dashed box  153 ) and a non-sterile region  154  in a surgical room. A sterile barrier  153  may be provided such that a proximal portion of device  150  (in region  154 ) is non-sterile and a distal portion of the device  150  (in region  154 ) is in the sterile region, which includes a mechanism (a barrier or sealed partition within the device  150 ) for not contaminating the sterile region  152  in an operating room. In one possible workflow, by allowing the non-sterile personnel such as a nurse to perform the proximal connections to a laser and clip on the launch fixture  150  to the launch base  160  and handing a protected OSS-enabled instrument  104  to the sterile personnel, the launch fixture  150  allows use of OSS-enabled devices  104  without breaking the sterile barrier. In another possible workflow, the launch base  160  is also sterile and connects to the support  162  over a sterile drape  155 . This combination also allows for the launch fixture  150  to be employed to enable the use of OSS instruments  102  without breaking the sterile barrier  153 . 
     Referring to  FIG. 2 , a launch fixture  150  suitable for coupling an OSS fiber device  104  to a flexible instrument  102  in a controlled manner is illustratively shown. The launch fixture  150  includes a fixation point or device  172  to clamp the optical fiber  104  and its protective tubing, housing, or similar structure  173  in place into the fixture  150 . A defined path  174  is formed to permit excess fiber to be included within the fixture  150  while not exceeding a specified minimum bend radius. This path  174  may also include features which allow for automatic alignment of the polarization of the OSS laser system to be performed while the instrument is connected to the OSS console. When a fiber undergoes a tight bend the index of refraction experienced by the light through that bend will vary depending on the orientation of the light. To mitigate these birefringence effects, optical shape sensing measurements are commonly performed with multiple light polarizations. One technique to optimally select (or ‘align’) those polarization states is to use the measured optical response through a known feature, such as a bend. An example of such a feature is a defined path  174  with sufficient curvature to induce birefringence effects in the fiber. These birefringence effects provide unique features in the measured optical signal that can be used for automatic alignment of the system polarization. Ideally, this curvature will have a tight radius to amplify the birefringence effects and thus allow for a more unique feature upon which to perform alignment. This alignment feature can exist prior to a launch region  176  within the launch fixture  150 . 
     The launch region  176  permits the OSS fiber device  104  to be physically attached to the fixture  150  in a defined manner (e.g., straight or with a known geometry). The path prior to the launch region  176  may have features  177  which ensure the fiber enters the launch region  176  in a controlled manner (e.g., pegs, radiused features, etc.). A path  178  (which may be included in path  174 ) acts as a buffer, or service loop, to allow for curvature induced path length changes to be accommodated by the fiber repositioning within the fixture  150  while not exceeding a specified minimum bend radius. Such a service loop may take several different forms, e.g., the service buffer loop of path  178  may include a 90 degree, 360 degree bend, etc. instead of or in addition to the 180 degree bend depicted in  FIG. 2 . A gap distance  171  of the path  178  provides slack for manipulating the fiber but protects the fiber from exceeding the minimum bend radius. 
     A fixation point or device  180  clamps the flexible instrument  102  to the fixture  150  and surface curvatures/fillets  182  ensure that the transition between the fixture  150  and the flexible instrument  102  occurs without negatively effecting the strain measurement of the OSS fiber  104 . Mechanical design features  184  allow the fixture  150  to be reproducibly connected to the launch fixture base  160  ( FIG. 1 ), or other launch fixtures in a known geometric manner. Screws, magnets, snap-fits, clips, pegs, or similar mechanisms can be employed to achieve this. Feature or features  184  with known geometry, curvature or shape, may be employed for registering the device  102  to other OSS-enabled devices, the patient and the imaging frame of reference  136 ,  138 . The feature(s)  184  may be employed for the dual purpose of attaching the fixture  150  to the launch base  160  and attaching fixtures  150  to each other. The feature(s)  184  may be directional shaped (e.g., square, triangle, etc.) to ensure that the base  160  and the fixtures  150  are properly aligned relative to one another. 
     The launch fixture  150  is depicted in an open configuration in  FIG. 2 . A lid (not shown) can be employed to cover the open launch fixture  150  or another launch fixture (not shown) may nest or be coupled to the launch fixture  150 . The lid or additional launch fixture ( 150 ) may be screwed or otherwise connected into place to both clamp the components into place (on the base  160 ) and to protect the fiber from the environment by employing features  186 . Feature  186  may include similar mechanism and described for features  184 . 
     An additional feature of the launch fixture  150  includes a defined path  179  for the fiber distal from the launch region  176  which can be used to correct for any rotation of the launch region during use. In practice, the fiber is clamped in place at the launch region  176 ; however, in some circumstances the fiber can ‘rotate’ within the clamp and thus any registrations can become inaccurate. By having a known shape distal from the launch region, this rotation can be corrected for. The defined path  179  may include a curved path in two or three dimensions, e.g., a semi-circle, compound curves (e.g., sinusoid), an arc, a coiled shape, etc. The defined path  179  may be included distally to the launch region  176  within the launch fixture  150  or may be included as a detachable module  169  that connects to the launch fixture (as depicted in  FIG. 2 ). 
     Referring to  FIG. 3 , a launch fixture base  160  is shown in accordance with one illustrative embodiment. The launch fixture base  160  includes features  190 , such as holes, pegs, detents, protrusions, etc. configured to rigidly attach to a fixed frame of reference within the operating theatre (e.g., the operating table or the like). The launch fixture base  160  includes the ability to be reproducibly connected to one or more launch fixtures  150  with a known geometric relationship. This may include features  192 , such as holes, pegs, detents, protrusions, etc. configured to permit easier connection and fixation of the launch fixture(s)  150  or a lid on the launch fixture(s)  150 . 
     Referring to  FIG. 4 , three launch fixtures  150 ,  151  and  153  are connected to a launch fixture base  160  which is, in turn, connected to an operating table (not shown) via steel rods and support structure  163  and appropriate clamps, etc. In this architecture, the transformations between the frames of reference of the individual launch fixtures (and hence the flexible instruments  102  connected to the launch fixtures  150 ,  151 ,  153 ) and the launch fixture base  160  are known. Assuming a transformation between the launch fixture base  160  and the patient or imaging system frame of reference is known, then different launch fixtures  150 ,  151 ,  153  can be connected to the launch fixture base  160  and used for imaged guided navigation without requiring a re-registration step. The known geometric relationship between each launch fixture  150 ,  151 ,  153  and the launch fixture base  160  can be used to minimize time spent registering each device to the patient/imaging system frame of reference. 
     In one embodiment, launch fixtures  150 ,  151 ,  153  can be rigidly attached to the launch fixture base  160  using threaded bolts  188 . A lid  165  may be employed as well and secured together with fixtures  150 ,  151 ,  153 . For example, additional launch fixtures  151 ,  153  can be attached to the initial launch fixture  150  with lid  165  using longer bolts. In other embodiments, magnets, clips, snap fits or similar rapid attachment components may be employed instead of bolts to attach and detach the launch fixture(s) from each other and the launch fixture base  160 . Quick connect or magnetic attachment mechanisms (e.g., snap together arrangements, clamps, clasps, tongue and groove, etc.) may be employed to make quick and secure but releasable connections between the base  160  and fixtures  150 ,  151 ,  153  and between fixtures  150 ,  151 ,  153 . The geometric relationship between adjacent launch fixtures  150 ,  151 ,  153  (and hence their instrument frames of reference) and the launch fixture base  160  can be used to ensure that re-registration of multiple devices is not required as devices are exchanged during a procedure. In addition, by locating the fixtures  150 ,  151 ,  153  and base  160  at a single location clutter is reduced and an organized and efficient operating theater is maintained. 
     Referring to  FIG. 5 , in another embodiment, launch fixtures  150 ′ couple to a launch fixture base  160 ′ independently (e.g., not stacked on each other). Examples of such an embodiment include a rack-style base or similar architecture where the fixtures can be stacked horizontally, vertically or angled with respect to an operating table or other reference structure. 
     In one embodiment, connection features  163  may include different shapes for receiving different types of OSS enabled devices  102 . For example, a square, triangle, circle, etc. feature  163  may be employed to limit the type of OSS enabled device  102  connected to the launch fixture  150 ′. For example, a guide wire may include a square connector, a catheter may include a round connector and an endoscope may include a triangular connector. 
     Referring to  FIG. 6 , in another embodiment, similar to that launch fixture  150 , a launch fixture  250  is shown capable of coupling two OSS fibers  104  to two flexible instruments  102  within a single fixture  250 . An entrance point  254  for one fiber and an exit point  255  for one flexible instrument  102  are depicted. An entrance point  256  for one fiber and an exit point  257  for another flexible instrument  102  are also depicted. In this embodiment, if two instruments  102  are employed within the single fixture  250 , one instrument  102  may use a buffer, or service loop  252  and, the other instrument  102  may not employ the service loop  252 . However, a service loop may be provided for both instruments in other embodiments. Other embodiments may employ a single fixture with a greater number of flexible instruments. A fiber path  258  may be employed for automatic alignment of light source polarization states, as described above. 
     Referring to  FIG. 7 , a modular launch fixture  350  is shown in accordance with one embodiment. The fixture  350  illustratively includes selected elements or features needed to couple an OSS fiber to a flexible instrument in a controlled manner. The launch fixture  350  in this particular embodiment adopts a modular approach to attaching each of a plurality of elements described above to a rail system or launch fixture base  362 . This rail  362  can be attached to an operating table and then registered to the patient and/or imaging system frame of reference. 
     The launch fixture  350  illustratively includes a launch region module  352 , a buffer or service loop module  354 , an excess fiber path module  356 , a fiber boot clamp module  358 , and a clamp module  360  for the flexible instrument  102 . Other modules  364  may be included. The modules  352 ,  354 ,  356 ,  358 ,  362 ,  364  are individually separable from the launch fixture base  360  and adjacent modules. The modular embodiment of the launch fixture  350  may include multiple flexible instruments and/or stackable launch fixtures, each with one or more flexible instruments. The fibers in each module may include optical connectors so that modules can be easily changed out as needed. 
     Referring to  FIG. 8A , a protective layer  380  (e.g., a plastic film, sterile drape or the like) is disposed between the launch base  160  and the launch fixture  150 , allowing a sterile device within a protected plastic  382  to clip on the non-sterile launch-base  160  while still having the packaging that maintains sterility. Others arrangements are also contemplated. 
     In another embodiment, the launch fixture base  160  can be multi-use, sterilizable and connect over a sterile drape  383 . The launch fixture  150  can be connected to the sterile launch fixture base  160  thus allowing the OSS device to be used within the sterile field. 
     Referring to  FIG. 8B , a protective partition  386  (e.g., a stainless steel wall) with sealed orifices  388  is disposed in the launch fixture  150 , allowing a sterile device on a distal side (with instrument  102 ) and a non-sterile device on a proximal side (with fiber  104 ). Others arrangements are also contemplated. 
     Referring to  FIG. 9 , in another embodiment, the launch fixture base  160  is coupled to a rail  402  or other structure such that the OSS enabled device  102  could be used for entering a body  131  at different locations, such as femoral access versus carotid access. The launch fixture base  160  could be repositioned at preset states or locations  404 ,  406  and lock into place by a clamp  408  or other securing device. The positions, orientations and transforms of the base  160  at these locations  404 ,  406  with respect to other locations would be known and thus, registering multiple OSS devices  102  would be straightforward and simple. In one embodiment, the launch fixture  150  and/or launch fixture base  160  may be robotically actuated and manipulated to different positions with or without the rail  402  (the rail  402  may also be robotically positioned). Translation and rotation of the rail  402 , the launch fixture  150  and/or launch fixture base  160  may be provided robotically for medical procedures (e.g., endovascular, endoluminal and/or orthopedic applications, etc.) or other applications. In another embodiment, translation along the rail  402  may be performed manually, and the transformations to the patient or imaging coordinate systems, or both, can be calculated by measuring the position along the rail  402  using a position sensing device (potentiometer, optical tracker, etc.). If a robot is employed, the fixtures  150  and base  160  may be registered to the robotic coordinate system. 
     Referring to  FIG. 10 , a method for optical shape sensing (OSS) includes providing a launch fixture for handling optical fiber in a controlled manner, in block  502 . The launch fixture includes a first fixation device configured to receive and secure an optical fiber, a fiber storage area configured to receive and maintain the optical fiber within specified dimensions, a second fixation device configured to receive and secure a flexible OSS enabled instrument, a launch region configured to receive and maintain the optical fiber in a known geometric configuration before entering the second fixation device, and at least one feature for aligning and coupling to a launch fixture base, which is configured to secure the launch fixture. The launch fixture may include other features as well, e.g., a defined path which can be used to correct for rotation of the fiber launch region (as described above). 
     In block  504 , the launch fixture is equipped with at least one OSS fiber, which is initially secured in the first fixation device, and at least one OSS enabled device, which is secured in the second fixation device. The OSS fiber is stowed in buffer or loop area configured to maintain minimum dimensions requirements to the fiber and to provide some slack for accommodating operational movement of the fiber without exceeding the requirements. In block  506 , the launch fixture is secured to a launch fixture base. The launch fixture base may be secured to an operating table, a rail system, robotic instrument, imaging system, etc. In one embodiment, the launch fixture base may be actuated to different position within an operating theater. 
     In block  508 , other launch fixtures are stacked on the launch fixture and/or a lid is placed over the launch fixture. In block  510 , the launch fixture or fixtures and/or fixture base are registered to at least one of a patient frame of reference and an imaging frame of reference, although other references may be employed. In block  512 , a sterile barrier may be employed through the launch fixture(s), between the launch fixture and the launch fixture base or between modules of a modular launch fixture. In block  514 , the flexible OSS enabled instrument is employed to sense a shape of the optical fiber. 
     In interpreting the appended claims, it should be understood that:
         a) the word “comprising” does not exclude the presence of other elements or acts than those listed in a given claim;   b) the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements;   c) any reference signs in the claims do not limit their scope;   d) several “means” may be represented by the same item or hardware or software implemented structure or function; and   e) no specific sequence of acts is intended to be required unless specifically indicated.       

     Having described preferred embodiments a launch fixture for optical shape sensing (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the disclosure disclosed which are within the scope of the embodiments disclosed herein as outlined by the appended claims. Having thus described the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.