Patent Abstract:
A system for imaging and treating tissue comprises a probe having a deflectable distal tip for carrying an imaging array and a delivery needle for advancement within a field of view of the imaging array. Optionally, the needle will carry a plurality of tines which may be selectively radially deployed from the needle. The imaging array will preferably be provided in a separate, removable component.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 13/023,383 (Attorney Docket No. 31992-711.301), filed Feb. 8, 2011, which is a continuation-in-part of application Ser. No. 12/198,861 (Attorney Docket No. 31992-711.201), filed on Aug. 26, 2008; this application is also a continuation-in-part of U.S. patent application Ser. No. 12/973,587 (Attorney Docket No. 31992-706.301) filed Dec. 20, 2010, which is a continuation of U.S. patent application Ser. No. 11/564,164 (Attorney Docket No. 31992-706.501) filed Nov. 28, 2006, now U.S. Pat. No. 7,874,986, which is a continuation-in-part of application Ser. No. 11/409,496 (Attorney Docket No. 31992-706.201) filed Apr. 20, 2006, now U.S. Pat. No. 7,815,571, the full disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to medical devices and methods. More particularly, the present invention relates to an imaging and therapy device having a deployable treatment needle or needles and a pivotal imaging array. 
         [0004]    Uterine fibroids are benign tumors in the uterine wall and are the most common tumor of the female pelvis. Fibroids afflict up to 30% of women of childbearing age and can cause significant symptoms including discomfort, pelvic pain, mennorhagia (excessive bleeding), anemia, infertility, and miscarriage. While fibroids may be located in the muscle (intramural), adjacent to the endometrium (submucosal), or in the outer layer of the uterus (subserosal), and can grow up to several centimeters in diameter. 
         [0005]    Current treatments for fibroids include both pharmaceutical and surgical intervention. Pharmaceutical treatments include the administration of NSAIDS, estrogen-progesterone combinations, and the like. Medications, however, are generally ineffective and are palliative rather than curative. Surgical interventions include myomectomy, where fibroids are removed in an open surgical procedure requiring laparotomy and general anesthesia, and hysterectomy, involving complete surgical removal of the uterus. Both these procedures are long and have significant blood loss. 
         [0006]    As improvements over open surgical procedures, several minimally invasive procedures have been developed. Laparoscopic myomectomy is a laparoscopic procedure requiring highly skilled laparoscopic gynecologists. Uterine artery embolization relies on blocking the uterine artery supplying blood to the fibroid by injecting small particles. While sometimes effective, common complications of arterial embolization include infection, premature menopause, and severe pelvic pain. A third approach relies on complete endometrial ablation, which is generally effective for treating bleeding but less reliable for treating fibroids. 
         [0007]    More recently, and of particular interest to the present invention, the use of radiofrequency needles and other ablation elements for treating individual fibroids via a transvaginal approach has been proposed. As described, for example, in U.S. Patent Publications 2006/0189972; 2007/0179380; and 2008/0033493, each of which is commonly assigned with the present application, a probe carrying a curved needle is used to treat individual fibroids. The probe carries on-board ultrasonic or other imaging so that the needle can be guided into the fibroid under direct observation. While highly effective in many cases, accurate advancement of a curved needle into a fibroid can be problematic. Moreover, use of a single needle does not always deliver sufficient energy to fully ablate relatively large fibroids. 
         [0008]    For these reasons, it would be desirable to provide alternative devices and methods for treating, ablating, or removing uterine fibroids and other tissue masses. It would be particularly desirable if such methods and devices were able to treat uterine fibroids which are large, difficult to penetrate, or which otherwise resist treatment with curved and laterally deployed needles. At least some of these objectives will be met by the inventions described below. 
         [0009]    2. Brief Description of the Background Art 
         [0010]    The following US Patent Publications discussed above are relevant to the present invention: 2006/0189972; 2007/0179380; and 2008/0033493. See also US Patent Publication 2007/0249936. The disclosures of each of these applications is incorporated herein by reference. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    The present invention provides apparatus and methods for imaging and treating fibroids and other tumors and tissue masses located in the walls of a uterus or other body cavity. The apparatus and systems comprise a straight shaft having a distal end and a proximal end. A delivery needle, preferably straight, is reciprocatably coupled to the shaft, typically being mounted in a straight lumen in the shaft, so that a tissue-penetrating tip of the needle can be distally advanced from the shaft along an axial path. The delivery needle may carry tines forming a needle array, deployable from within the delivery needle. A tip or other structure is pivotally attached to the distal end of the shaft and is moveable between a position parallel to the axial path and a position at an acute or right angle relative to the axial path. The pivotable tip carries or comprises an ultrasonic imaging array, and the tip can be oriented to align a field of view of the imaging array with the needle as the needle is advanced along the axial path. 
         [0012]    The combination of a straight shaft, delivery needle, and pivotally attached tip or imaging array has a number of advantages. The straight shaft and needle can be advanced with precision into tissue surrounding the body cavity, where the needle can be made sufficiently strong to resist unwanted deflection of the type which could occur with other needle configurations. The use of a delivery needle and shaft also enables and facilitates the deployment of a needle array, including a plurality of tines, from the delivery needle to increase the volume of tissue being treated with the needle array. The pivotable imaging array allows straightening of the imaging array to provide a low profile for introduction through the cervix into the uterus, while also allowing reorientation to cover a wide range of viewing fields after entering the uterus or other body cavity to permit locating fibroids and other tumors and to further follow the advance of the needle array into the fibroids or other tumors. It should be noted that in the preferred embodiment, the delivery needle is for delivery only, and does not provide treatment. In alternative embodiments, the delivery needle may be used for treatment. The pivotable tip further allows the effective field of view of the ultrasound image to be increased by pivoting the tip, which has the effect of sweeping the ultrasound image. The tip may be pivoted to enhance the view of the delivery needle and/or the needle array, including tines. 
         [0013]    In a preferred embodiment, an imaging and therapeutic delivery system includes a straight shaft having a distal end and a proximal end and a straight needle reciprocatably coupled to the shaft so that a tissue-penetrating tip on the needle can be distally advanced from the shaft along an axial path and a tip pivotally attached to the distal end of the shaft and movable between a position parallel to the axial path and a position at an acute or right angle relative to the axial path. An ultrasonic imaging array is carried by the pivotally attached tip, wherein the tip can be oriented to align a field of view of the imaging array with the needle as it is advanced along the axial path so as to sweep the ultrasound field of view relative to the needle and anatomy to be imaged. The tip is offset from the axial path of the needle. 
         [0014]    In certain preferred embodiments, an imaging and therapeutic delivery system includes a straight shaft having a distal end and a proximal end. A needle is reciprocatably coupled to the shaft so that a tissue-penetrating tip on the needle can be distally advanced from the shaft along an axial path, said needle exiting said shaft at an angle of 0 degrees relative to said shaft. A tip is pivotally attached to the distal end of the shaft and movable between a position parallel to the axial path and a position at an acute or right angle relative to the axial path. An ultrasonic imaging array is carried by the pivotally attached tip, wherein the tip can be oriented to align a field of view of the imaging array with the needle as the needle is advanced along the axial path so as to sweep the ultrasound field of view relative to the needle and anatomy to be imaged. 
         [0015]    In the preferred embodiment, the imaging array will be formed on an imaging core, where the imaging core is removably positionable in the straight shaft so that the imaging array extends into the pivotally attached tip. The straight shaft will usually be rigid while the imaging core is relatively flexible, allowing the imaging core to bend at the point where the tip is pivotally attached to the shaft. In alternate embodiments, the needle assembly may be attached directly to the ultrasound probe or the imaging core may be hinged at the point where the tip is pivotally attached to the shaft. 
         [0016]    In certain preferred embodiments, the delivery needle will carry a needle array having at least one tine which can be advanced from the delivery needle, usually carrying a plurality of tines, where the tines are reciprocatably attached to the delivery needle to permit deployment and retraction, usually after the delivery needle has been advanced into target tissue. A plurality of tines will usually be arranged to radially diverge from the delivery needle as the tines are distally advanced. Optionally, at least one additional tine may be reciprocatably mounted on the delivery needle in a range to be advanced axially from the needle, often forming a center axis to a symmetric deployment of radially diverging tines. In order to localize the treatment, the tines may be electrically conductive while the delivery needle itself is electrically non-conductive or insulating. In such cases, the tines may be arranged to be connected to a single pole of an electrosurgical power supply in order to provide for monopolar treatment. Alternatively, a certain number of the tines may be adopted to one pole of the power supply while others are connected to the other pole, providing for bipolar treatment. 
         [0017]    In certain exemplary embodiments, the imaging and therapeutic delivery system will further comprise a handle attached to the proximal end of the straight shaft. The handle may include a lever coupled to the pivotally attached distal tip by one or more pull rods. The lever can be pulled or pushed to actuate the pull rod(s) to pivot the tip. Additionally, the handle may include a first slide mechanism coupled to the delivery needle, where the slide mechanism can be reciprocated to advance and retract the needle along the axial path. In the embodiments which include the plurality of tines, the tines may be reciprocatably attached to the delivery needle and connected to a second slide mechanism on the handle, optionally being disposed on the first slide mechanism itself, to advance and retract the tines relative to the needle. Optionally, a stop structure may be disposed on the pivotally attached tip so that the stop structure prevents advancement of the needle when the tip is parallel to the axial path of the needle. 
         [0018]    The present invention also comprises methods for treating uterine fibroids. The methods include introducing a straight shaft into the uterus. Uterine fibroids are then located using an ultrasonic imaging transducer carried by or formed as part of a pivotable tip attached to a distal end of the shaft. The tip is pivoted to reposition a field of view of the ultrasonic transducer carried by the tip. Optionally, the tip may block advancement of the needle when disposed parallel to the shaft (prior to deployment) and allow advancement when pivoted from the parallel orientation. A delivery needle may be axially advanced from the distal tip of the shaft into tissue near or in a uterine fibroid located using the ultrasonic transducer. Advancement of the needle may be observed by the transducer by aligning the field of view with the needle advancement. 
         [0019]    In preferred aspects of the methods of the present invention, the shaft is introduced to the uterus via a transvaginal and transcervical introduction. Locating fibroids may comprise manually rotating and translating the shaft to scan the uterine wall with the ultrasonic transducer. Locating may also comprise pivoting the ultrasonic transducer to adjust the field of view. Optionally, an array including a plurality of tines may be advanced from the delivery needle after the needle has been advanced into tissue at or near the uterine fibroid. This method will sweep the ultrasound field of view relative to the needle and anatomy to be imaged. The fibroid is then treated by delivering energy from the needle and/or tines into the fibroid, typically radiofrequency energy, including both monopolar and bipolar radiofrequency energy. Usually, the tines will be electrically active to deliver the radio frequency energy while the delivery needle is electrically non-conductive to limit the distribution of energy in the uterine wall or other tissue being treated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIGS. 1A and 1B  are perspective views of an imaging and therapeutic delivery system constructed in accordance with the principles of the present invention shown with portions broken away. In  FIG. 1A , a delivery needle and array including radially diverging tines are retracted within the shaft of the device, and a pivotally attached tip is shown in axial alignment with the axial deployment path of the needle. In  FIG. 1B , the delivery needle and associated tines are shown in their deployed configuration with the pivotally attached tip shown oriented at an acute angle relative to the axial advancement path of the needle. 
           [0021]      FIG. 2  illustrates the imaging and therapeutic delivery system of  FIGS. 1A and 1B  in cross-section.  FIG. 2A  is a detail of the distal tip of the device illustrated in  FIG. 2 .  FIGS. 2B and 2C  illustrate a stop structure on the pivotally attached tip which prevents needle advancement prior to deployment of the tip. 
           [0022]      FIGS. 3A and 3B  illustrate the pivotal tip deployment mechanism in detail, also in cross-section. 
           [0023]      FIGS. 4A-4C  illustrate the relative movement of the deployment mechanism and the pivotal tip, as the deployment mechanism is actuated. 
           [0024]      FIGS. 5 and 6  are side and top views of the imaging and therapeutic delivery system shown with portions broken away in a non-deployed configuration. 
           [0025]      FIGS. 7 and 8  are views similar to  FIGS. 5 and 6 , except that the delivery needle has been deployed and the pivotally attached tip has been positioned at an acute angle. 
           [0026]      FIGS. 9 and 10  are views similar to  FIGS. 5 and 6  and  FIGS. 7 and 8 , respectively, further illustrating the deployment of the needle array, comprising radially diverging tines from the delivery needle. 
           [0027]      FIGS. 11A and 11B  illustrate deployment of the delivery needle and tines into tissue. 
           [0028]      FIG. 12  illustrates a system without an ablation needle. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring to  FIGS. 1A and 1B , an imaging and therapeutic delivery system constructed in accordance with the principles of the present invention comprises a straight shaft assembly  12  including a hollow rod  14  and a needle tube  16 . A tip  18  which is adapted to receive an ultrasonic imaging array (shown in broken line at  38 ) is pivotally attached to a distal end  20  of the hollow rod  14  of the straight shaft assembly  12 . A needle and tine array  21  ( FIG. 1B ) is deployed through a lumen or central passage in the needle tube  16  at a distal end  20  of the shaft assembly  12 . A handle assembly  22  is attached to a proximal end  24  of the straight shaft assembly  12  and includes a pivoting mechanism  26 , typically found on its lower surface as illustrated, for selectively pivoting the imaging array tip  18  between a low profile configuration where the tip  18  is axially aligned with the axis of the shaft assembly  12 , as illustrated in  FIG. 1A , and a deflected configuration where the tip  18  is oriented at an acute or right angle relative to the axis of the shaft, as illustrated in  FIG. 1B . The tip  18  may be placed in its axially aligned, low profile configuration for introduction to the body cavity, for example through the cervix into the uterus, and may be shifted to its deflected configuration in order to image tissue and/or to track deployment of the needle/tine array  21 . As described in more detail below, the pivoting mechanism  26  includes a lever  28  which may be manually retracted from the distally advanced configuration shown in  FIG. 1A  to the proximally retracted configuration shown in  FIG. 1B  in order to pivot the tip  18 . 
         [0030]    The handle  22  will also include a delivery needle/tine deployment mechanism  30  which includes a first slide subassembly  32  and a second slide subassembly  34 . The handle will usually further include a port  36  at its proximal end. Port  36  allows introduction of an ultrasonic or other imaging core, where the imaging core has an imaging array  38 , typically an ultrasonic imaging array as described in detail in copending application Ser. No. 11/620,594; and parent application Ser. Nos. 11/564,164; and 12/973,587, the full disclosures of which are incorporated herein by reference. The proximal end of the handle will also allow electrical connections to be made to the needle/tine array. Additionally, the distal end of the handle will provide a standard luer connection for the infusion of non-conductive coupling fluids. 
         [0031]    Optionally, a stop structure  19  may be attached to an upper surface of the pivotally attached tip  18 , as illustrated in  FIGS. 2B and 2C . When the tip  18  is parallel to the axis of the shaft (hollow rod  14 ), the stop structure  19  will block the advancement path of the needle  16  (as shown in  FIG. 2B ). This is advantageous since it prevents accidental needle advancement while the shaft assembly  12  is in the introductory configuration. Deployment of the tip  18 , as shown in  FIG. 2C , moves the stop structure  19  out of the advancement path of the needle  16 , as described below. 
         [0032]    Referring now to  FIGS. 2, 2A, 3A, and 3B , operation of the pivot mechanism  26  for selectively deflecting the tip  18  disposed at the distal end of the straight shaft assembly  12  will be described. For clarity, components of the first slide assembly  32  and second slide assembly  34  have been removed from the view in  FIG. 2 . The tip  18  is pivotally attached at the distal end  20  of the straight shaft assembly  12  by a pivot pin  40  or similar structure, as best seen in  FIG. 2A . A pair of pull rods  42  are attached at anchors  44  so that drawing the wires in a proximal direction will deflect the tip  18  from an axially aligned configuration, as shown in broken line in  FIG. 2A , to the deflected configuration, as shown in full line in  FIG. 2A . The rods  42  extend through tubes  46  disposed on each side of the hollow rod  14  of the shaft assembly  12 . As best seen in  FIGS. 3A and 3B , the rods  42  are attached at their proximal ends to a rotating anchor  50  disposed in lever  28 . Thus, by drawing the lever  28  proximally, as shown in  FIG. 3A , the tip  18  may be laterally deflected, as shown in full line in  FIG. 2A . Conversely, by pushing the lever  28  in a distal direction, as shown in  FIG. 3B , the tip  18  may be returned to the axially aligned configuration as shown in broken line in  FIG. 2A . The lever  28  is pivotally attached to the body of handle  22  by a pivot pin  48  so that the anchor  50  is offset from the point of rotation of the lever  28 . Thus, the anchor  50  is actually translated as the lever is rotated back and forth about the pivot pin  48 . 
         [0033]    A locking pin  52  allows the lever  28  to be selectively locked in place to hold the pivot tip  18  in a fixed orientation. Locking pin  52  is mounted in a central passage  54  of the lever  28  and carries a pin  56  which seats in one of a plurality of pockets  58  formed in an arcuate locking strip  60 . Thus, the lever  28  can be released by pressing the pin  52  against spring  62  so that the pin  56  is lifted out of the pocket  58 , as shown in  FIG. 3A . In this configuration, the lever may be moved freely back and forth to deploy the tip  18 . When the tip  18  is in its desired location, the locking pin  52  may be released to permit pin  56  to engage the closest pocket  58  where it is held in place by spring  62 . It will be appreciated that the lever  28  will typically be advanced forwardly to close the tip  18  to a low profile configuration for introducing the imaging and therapy delivery system  10  to the patient for treatment, for example through the cervix into the uterus. Once in place, the lever  28  can be unlocked using the locking pin  52  and oriented to a desired angle relative to the shaft assembly  12  to permit imaging and, in particular, to allow advancement of the delivery needle  70  in the tissue to be observed. 
         [0034]    Referring now to  FIGS. 4A-4C , use of the lever  28  for deflecting the tip  18  is illustrated. Initially, the tip  18  is axially aligned with the axis of the shaft assembly  12  and the lever  28  is in its forward or distal-most position, as shown in  FIG. 4A . By depressing locking pin  52 , as shown in  FIG. 4B , lever  28  may be drawn proximally as indicated by the adjacent arrow, to deflect the tip  18  away from the axis of shaft  12 , as shown by the arrow adjacent the tip in  FIG. 4B . When the lever  28  reaches its fully proximal position, as shown in  FIG. 4C , the tip  18  has been fully deflected away from the axis of shaft assembly  12 . Note that slide subassemblies  32  and  34  (for extending delivery needle  70  and needle array  21 ) have not been activated in  FIGS. 4A-4B . 
         [0035]    Referring now to  FIGS. 5-10 , operation of the first slide subassembly  32  and the second slide subassembly  34  will be described. For clarity, portions of the pivot mechanism  26  have been removed from these views. Prior to deployment, as shown in  FIGS. 5 and 6 , the needle/tine array  21  is fully drawn into the central passage of needle tube  16 . Needle tube  16  has an open distal tip  64  through which the delivery needle and tines will emerge when advanced using the slide subassemblies  32  and  34 . 
         [0036]    The first slide subassembly  32  comprises a reciprocating carriage  66  having a coupling  68  attached to a proximal end of the needle  70 . The carriage  66  may be axially advanced and retracted by manually pressing buttons  72  to disengage pins  74  ( FIG. 5 ) from pockets  76  in a straight locking strip  78 . Once the pins  74  are disengaged, the carriage  66  may be distally advanced, as shown in  FIGS. 7 and 8 , to advance tip  80  of needle  70  from the distal end of the needle tube  16 . The buttons  72  may then be released to allow pins  74  to reenter the adjacent pockets  76  in the locking strip  78 , thus locking the needle  70  in place. 
         [0037]    Referring now in particular to  FIGS. 9 and 10 , a plurality of radially diverging tines  82  may be deployed from the distal end of needle  70  using the second slide subassembly  34  which includes a thumb slide  84 . The thumb slide  84  is reciprocatably carried in the carriage  66  so that the thumb slide will advance the tines relative to the needle. The thumb slide is connected to a tine rod  86  which enters a hollow central passage or lumen of the needle  70  and is coupled to the plurality of tines  82  so that advancement of the thumb slide  84  from the retracted position shown in  FIGS. 7 and 8  to the distally advanced position shown in  FIGS. 9 and 10  causes the tines  82  to emerge from the distal end of the needle  70 . The tines  82  are preferably formed from a straight, resilient metal, such as stainless steel, nickel titanium, or the like, and are deflected outwardly by ramps (not shown) in the distal end of the needle. Optionally, a lockout circuit (not shown) may be provided to prevent energizing the tines if the tines are not fully advanced. 
         [0038]    The use of the imaging and therapeutic delivery system  10  of the present invention is illustrated in  FIGS. 11A and 11B . After imaging using the imaging array  38  carried on or in tip  18 , the needle  70  is advanced into target tissue identified by the imaging using the first slide subassembly  32 , as shown in  FIG. 11A . Usually, the position of the tip  18  will be adjusted to assure that travel of the needle  70  into the tissue may be observed. After the location of the needle tip  80  has been confirmed, the thumb slide  84  of the second slide subassembly  34  may then be advanced, as shown in  FIG. 11B , to extend the tines  82  into the tissue. In the preferred embodiments of the present invention, the needle  70  and tines  82  will be rotatably connected to the remainder of the device to allow the handle to be rotated, thus rotating the imaging array  38 , to facilitate imaging even after the needle and tines have been deployed. 
         [0039]    Referring now to  FIG. 12 , a delivery system  110  without an ablation needle is illustrated. A deflectable distal tip  126  of the rigid shaft  116  may be deflected by the use of pull or tensioning wire(s) housed within the shaft  116 . Deflection may occur at a true mechanical pivot or at a flexible zone at the shaft distal end  118 . As discussed above, when the delivery shaft  116  is deflectable by a user, various needles may be used to match the amount of deflection provided by the distal tip  126  as well as the amount of tilt provided by the ultrasound array  112 . Hence, a needle guide  144  will typically be empty until the distal end  118  of the shaft  116  is deflected. For example, the shaft  116  may be inserted in a straight configuration. The distal tip  126  may then be deflected until a target anatomy is identified. A needle is then back loaded within the guide passage  170  that corresponds to the amount of the deflection. 
         [0040]    Table I below illustrates possible viewing angles κ that may be achieved by the cumulative effects of the shaft bending angle β (e.g., either through active deflection of the distal tip or a pre-shaped or pre-bent distal tip) and the ultrasound tilting angle α. The matching needle angles θ based on the possible viewing angles κ are further illustrated. In example 1, the shaft  116  is in a straight configuration so that the viewing angle κ is provided solely by the tilting angle α of the ultrasound array  112 . In example 4, the needle  114  will have a straight configuration. In example 5, a non-tilted and non-bent ultrasound array  112  version is covered. It will be appreciated that the viewing angle κ will be more than the bend angle β of the shaft  116  due to the additive effect of the tilting angle α of the ultrasound array  112 . This allows the bend on the distal tip  126  of the shaft  116  to be shallower without compromising the cumulative viewing angle κ, which is of particular benefit for patient insertion considerations. In the case of a deflectable distal tip  126  in which insertion may be implemented in a straight configuration, the tiled ultrasound angle α still aids in reducing the needle angle θ. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                   
                 Viewing Angle 
                 Tilt Angle 
                 Bend Angle 
                 Needle Angle 
               
               
                 Example 
                 (κ) 
                 (α) 
                 (β) 
                 (θ) 
               
               
                   
               
             
             
               
                 1 
                 7°-10° 
                 7°-10° 
                 0° 
                 80° 
               
               
                 2 
                 20° 
                 7°-10° 
                 10°-13° 
                 70° 
               
               
                 3 
                 45° 
                 7°-10° 
                 35°-38° 
                 45° 
               
               
                 4 
                 90° 
                 7°-10° 
                 80°-83° 
                  0° 
               
               
                 5 
                  0° 
                 0° 
                 0° 
                 90° 
               
               
                   
               
             
          
         
       
     
         [0041]    While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.

Technology Classification (CPC): 0