Abstract:
A catheter that creates enhanced lesions uses a needle electrode assembly and employs diffuse reflectance optical spectroscopy, including optical transmissive and refractive spectroscopy before, during or after ablation to assess tissue attributes, including malignancy and/or necrosis. The catheter comprises an elongated catheter body, a control handle, and a longitudinally movable needle electrode assembly and one or more optical wave guides extending from the control handle and through the catheter body, wherein the needle electrode assembly is adapted for penetrating and ablating tissue at a distal end of the catheter and at least one optical waveguide is adapted to collect light refracted from the tissue at or near the distal end of the catheter. An integrated ablation and spectroscopy system of the present invention comprises an RF generator, a light source and a light analyzer adapted to analyze the light collected by the at least one waveguide.

Description:
FIELD OF INVENTION 
       [0001]    This invention relates to catheters, in particular, pulmonary catheters for ablation and tissue diagnostics. 
       BACKGROUND 
       [0002]    Radiofrequency (RF) ablation of cardiac and other tissue is a well-known method for creating thermal injury lesions at the tip of an electrode. Radiofrequency current is delivered between a skin (ground) patch and the electrode. Electrical resistance at the electrode-tissue interface results in direct resistive heating of a small area, the size of which depends upon the size of the electrode, electrode tissue contact, and current (density). Further tissue heating results from conduction of heat within the tissue to a larger zone. Tissue heated beyond a threshold of approximately 50-55 degrees C. is irreversibly injured (ablated). 
         [0003]    Resistive heating is caused by energy absorption due to electrical resistance. Energy absorption is related to the square of current density and inversely with tissue conductivity. Current density varies with conductivity and voltage and inversely with the square of radius from the ablating electrode. Therefore, energy absorption varies with conductivity, the square of applied voltage, and inversely with the fourth power of radius from the electrode. Resistive heating, therefore, is most heavily influenced by radius, and penetrates a very small distance from the ablating electrode. The rest of the lesion is created by thermal conduction from the area of resistive heating. This imposes a limit on the size of ablation lesions that can be delivered from a surface electrode. 
         [0004]    Theoretical methods to increase lesion size would include increasing electrode diameter, increasing the area of electrode contact with tissue, increasing tissue conductivity and penetrating the tissue to achieve greater depth and increase the area of contact, and delivering RF until maximal lesion size has been achieved (60-90 seconds for full maturation). 
         [0005]    The electrode can be introduced to the tissue of interest directly (for superficial/skin structures), surgically, endoscopically, laparoscopically or using percutaneous transvascular (catheter-based) access. Catheter ablation is a well-described and commonly performed method by which many cardiac arrhythmias are treated. Needle electrodes have been described for percutaneous or endoscopic ablation of solid-organ tumors, lung tumors, and abnormal neurologic structures. 
         [0006]    Catheter ablation is sometimes limited by insufficient lesion size. Ablation of tissue from an endovascular approach results not only in heating of tissue, but heating of the electrode. When the electrode reaches critical temperatures, denaturation of blood proteins causes coagulum formation. Impedance can then rise and limit current delivery. Within tissue, overheating can cause steam bubble formation (steam “pops”) with risk of uncontrolled tissue destruction or undesirable perforation of bodily structures. In cardiac ablation, clinical success is sometimes hampered by inadequate lesion depth and transverse diameter even when using catheters with active cooling of the tip. Theoretical solutions have included increasing the electrode size (increasing contact surface and increasing convective cooling by blood flow), improving electrode-tissue contact, actively cooling the electrode with fluid infusion, changing the material composition of the electrode to improve current delivery to tissue, and pulsing current delivery to allow intermittent cooling. 
         [0007]    Needle electrodes improve contact with tissue and allow deep penetration of current delivery to areas of interest. Ablation may still be hampered by the small surface area of the needle electrode such that heating occurs at low power, and small lesions are created. An improved catheter with needle ablation is disclosed in U.S. Pat. No. 8,287,531, the entire disclosure of which is hereby incorporated by reference. 
         [0008]    The need and demand for an accurate, non-invasive method for determining biological attributes of tissue are well-documented. Accurate, noninvasive determination of various disease states could allow faster, more convenient screening and diagnosis, allowing more effective treatment. Method and apparatus employing optical spectroscopy for determining tissue attributes are known. For example, U.S. Pat. No. 7,623,906 discloses a method and an apparatus for a diffuse reflectance spectroscopy which includes a specular control device that permits a spectroscopic analyzer to receive diffusely reflected light reflected from tissue. U.S. Pat. No. 7,952,719 discloses an optical catheter configuration combining Raman spectroscopy with optical fiber-based low coherence reflectometry. U.S. Pat. No. 6,377,841 discloses the use of optical spectrometry for brain tumor demarcation. 
         [0009]    Portions of light incident on tissue may be transmitted through the tissue, absorbed as heat, refracted, specularly reflected and diffusely reflected. Light that undergoes multiple refractions within tissue may contain information concerning biological attribute(s) of interest. 
         [0010]    Without a catheter that is adapted for both tissue diagnostics and ablation, the use of a separate ablation treatment catheter following tissue diagnosis, including diagnosis by optical spectroscopy, can increase cost and duration of the procedure and pose a risk that the ablation treatment catheter may not be returned to the exact diagnosis location to deliver ablation energy. 
         [0011]    Accordingly, it is desirable for a catheter to have at least an electrode needle adapted for both ablation and optical spectroscopy so that tissue diagnostics and ablation can be performed with a single catheter. Such a catheter would provide a “see and treat” device that would reduce procedure time and significantly reduce, if not eliminate, the risk of not returning to the exact biopsy location to deliver ablation treatment. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention addresses the above concerns by providing a catheter that creates enhanced lesions using a needle electrode assembly and employs optical spectroscopy, including transmissive and refractive spectroscopy before, during or after ablation to assess tissue attributes, including malignancy and/or necrosis. The catheter comprises an elongated catheter shaft, a control handle, and a needle electrode assembly that extends through the catheter shaft and the control handle, which can be advanced distally or retracted proximally relative to the catheter shaft for irradiating, penetrating and ablating a target tissue site. The distal end of the needle electrode assembly is adapted to penetrate tissue surface and ablate tissue at a depth below the tissue surface. The distal end of the needle electrode assembly is also adapted to irradiate tissue and collect optical data by providing at least one wave guide, including, for example, a fiber optic, that can transmit light energy from the catheter to an optical analyzer, e.g., a spectrometer. In that regard, the wave guide has a distal end generally coterminous with a distal end of the needle to emit light energy onto or into the target tissue. Light energy that has interacted with the target tissue is detected by the same wave guide or an additional collector wave guide. The one or more wave guides may be housed in the needle electrode assembly or mounted in a tip electrode provided at a distal end of the catheter. 
         [0013]    The present invention includes an integrated catheter-based ablation and spectroscopy system having the aforementioned catheter, an RF generator for providing RF energy to the needle electrode assembly, a light source to provide light energy to illuminate target tissue, and an optical analyzer, for example, a spectrometer, to detect and analyze optical data collected by the wave guides. In that regard, it is understood that the spectrometer is any instrument used to probe a property of light as a function of its portion of the electromagnetic spectrum, typically its wavelength, frequency, or energy. The property being measured is often, but not limited to, intensity of light, but other variables like polarization can also be measured. Technically, a spectrometer can function over any range of light, but most operate in a particular region of the electromagnetic spectrum. 
         [0014]    The system may also include a patient interface unit and a communication (COM) unit, a processor and a display, where the COM unit provides electronics for ECG, electrogram collection, amplification, filtering and real-time tracing of catheter distal tip and the PIU allows communication with various components of the system, including signal generator, recording devices, etc. The system may include a location pad with magnetic field generators (e.g., coils) to generate magnetic fields within the patient&#39;s body. Signals detected by a sensor housed in the catheter in response to the magnetic fields are processed by the processor order to determine the position (location and/or orientation) coordinates of the catheter distal end. Other signals from the catheter, for example, tissue electrical activity and temperature, are also collected by the catheter and transmitted to the COM unit and the processor via the PIU for processing and analysis. 
         [0015]    In one embodiment, the catheter of the present invention comprises an elongated catheter body, a control handle, and a longitudinally movable needle electrode assembly and one or more optical wave guides extending from the control handle and through the catheter body, wherein the needle electrode assembly is adapted for penetrating and ablating tissue at a distal end of the catheter and at least one optical waveguide is adapted to collect light refracted from the tissue at or near the distal end of the catheter. 
         [0016]    In a more detailed embodiment, the needle electrode assembly has an elongated proximal portion and a shorter distal “needle” portion, and the at least one optical waveguide extends alongside or within lumens of the proximal and distal portions. The distal needle portion can be advanced and retracted through an axial passage formed in a distal tip electrode mounted on a distal end of the catheter body. A ring electrode is mounted proximally of the distal tip electrode. Each of the distal needle portion, the distal tip electrode and the ring electrode is configured within the catheter for separate and independent selective ablation. 
         [0017]    In a more detailed embodiment, the catheter has an emitter fiber optic and a collector fiber optic that extend through the lumens of the needle electrode assembly. Each has a distal end coterminous with the distal end of the distal needle portion, which is beveled to facilitate the distal end piercing and penetrating tissue. The catheter includes a deflection control handle and a needle control handle. A proximal end of the needle electrode assembly is housed in the needle control handle and responsive to a control configured to advance the distal needle portion past a distal end of the catheter body. The needle control handle is also configured to retract the distal needle portion. 
         [0018]    An embodiment of the integrated ablation and spectroscopy system of the present invention comprises the aforementioned catheter, an RF generator adapted to provide RF energy to the needle electrode assembly, a light source adapted to provide light energy for the catheter wave guides, and a light analyzer adapted to analyze the light collected by the at least one waveguide. The system may further include a patient interface unit, a communication unit, a processor, and a display, wherein the patient interface unit is adapted to send and receive signals from the RF generator and the communication unit, wherein the communication unit is adapted to send and receive signals from the patient interface unit, wherein the processor is adapted to send and receive signals from the communication unit, and wherein the display is adapted to receive signals from the processor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
           [0020]      FIG. 1  is a perspective view of a catheter of the present invention, in accordance with one embodiment. 
           [0021]      FIG. 2A  is a side cross-sectional view of the catheter of  FIG. 1 , including a junction between a proximal shaft and a distal shaft, along a first diameter. 
           [0022]      FIG. 2B  is a side cross-sectional view of the catheter of  FIG. 1 , including a junction between a proximal shaft and a distal shaft, along a second diameter generally perpendicular to the first diameter of  FIG. 2A . 
           [0023]      FIG. 2C  is an end cross-sectional view of the distal shaft of  FIGS. 2A and 2B , taken along line C-C. 
           [0024]      FIG. 3  is a side cross-sectional view the distal shaft including a needle electrode assembly of the present invention, in accordance with one embodiment. 
           [0025]      FIG. 3A  is an end cross-sectional view of the distal shaft of  FIG. 3 , taken along line A-A. 
           [0026]      FIG. 3B  is an end cross-sectional view of the distal shaft of  FIG. 3 , taken along line B-B. 
           [0027]      FIG. 4  is a side cross-sectional view of a puller wire T-anchor, in accordance with one embodiment. 
           [0028]      FIG. 5  is an isometric view of a distal shaft of the catheter of  FIG. 1 , being deployed in a right atrium. 
           [0029]      FIG. 5A  is a detailed view of a distal end of the distal shaft of  FIG. 5 . 
           [0030]      FIG. 6  is a side cross-sectional view of the needle control handle of  FIG. 1 . 
           [0031]      FIG. 6A  is a detailed view of Area A in  FIG. 6 . 
           [0032]      FIG. 6B  is a detailed view of Area B in  FIG. 6 . 
           [0033]      FIG. 7  is a schematic diagram of a system of the present invention, in accordance to one embodiment. 
           [0034]      FIG. 7A  is a block diagram of the system of  FIG. 7 . 
           [0035]      FIG. 8  is a perspective view of a catheter of the present invention, in accordance with another embodiment. 
           [0036]      FIG. 8A  is an end cross-sectional view of a distal tip electrode of  FIG. 8 , taken along line A-A. 
           [0037]      FIG. 8B  is a side cross-sectional view of the distal tip electrode of  FIG. 8A , taken along line B-B. 
           [0038]      FIG. 8C  is a side cross-sectional view of the distal tip electrode of  FIG. 8B , taken along C-C. 
           [0039]      FIG. 8D  is a side cross-sectional view of a deflectable section of  FIG. 8 , taken along line D-D. 
           [0040]      FIG. 8E  is a side cross-sectional view of a deflection control handle of  FIG. 8 , taken along E-E. 
           [0041]      FIG. 8F  is a side cross-sectional view of a needle control handle of  FIG. 8 , taken along F-F. 
           [0042]      FIG. 8G  is a detailed view of a connector of  FIG. 8 . 
           [0043]      FIG. 8H  is an end cross-sectional view of the deflectable section of  FIG. 8D , taken along line H-H. 
           [0044]      FIG. 9  is an isometric view of a distal shaft of the catheter of  FIG. 8 , being deployed in a lung. 
           [0045]      FIG. 9A  is a detailed view of a distal end of the distal shaft of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    As shown in  FIG. 1 , the catheter  10  comprises an elongated catheter body  12  having a proximal shaft  13 , a distal shaft  14 , a deflection control handle  16  attached to the proximal end of the proximal shaft, and a needle control handle  17  attached indirectly to the catheter body  12  proximal of the deflection control handle  16 . 
         [0047]    With reference to  FIGS. 2A and 2B , the proximal shaft  13  comprises a single, central or axial lumen  18 . The proximal shaft  13  is flexible, i.e., bendable, but substantially non-compressible along its length. The proximal shaft  13  may be of any suitable construction and made of any suitable material. A presently preferred construction comprises an outer wall  22  made of polyurethane or nylon. The outer wall  22  comprises an imbedded braided mesh of stainless steel or the like to increase torsional stiffness of the proximal shaft  13  so that, when the deflection control handle  16  is rotated, the distal shaft  14  of the catheter  10  will rotate in a corresponding manner. 
         [0048]    The outer diameter of the proximal shaft  13  is not critical, but is preferably no more than about 8 French. Likewise the thickness of the outer wall  22  is not critical. In the depicted embodiment, the inner surface of the outer wall  22  is lined with a stiffening tube  20 , which can be made of any suitable material, preferably polyimide. The stiffening tube  20 , along with the braided outer wall  22 , provides improved torsional stability while at the same time minimizing the wall thickness of the catheter, thus maximizing the diameter of the single lumen. The outer diameter of the stiffening tube  20  is about the same as or slightly smaller than the inner diameter of the outer wall  22 . 
         [0049]    As shown in  FIGS. 2A ,  2 B and  2 C, the distal shaft  14  comprises a short section of multi-lumened tubing  19  having, for example, at least three lumens, namely a first lumen  30 , a second lumen  31 , and a third off-axis puller wire lumen  32  for uni-directional deflection, and a fourth off-axis lumen  33  diametrically opposite of lumen  32  for bidirectional deflection. The tubing  19  is made of a suitable non-toxic material that is preferably more flexible than the proximal shaft  13 . A suitable material for the tubing  19  is braided polyurethane, i.e., polyurethane with an embedded mesh of braided stainless steel or the like. The outer diameter of the distal shaft  14 , like that of the proximal shaft  13 , is preferably no greater than about 8 French. 
         [0050]    A suitable means for attaching the proximal shaft  13  to the distal shaft  14  is illustrated in  FIGS. 2A and 2B . The proximal end of the distal shaft  14  comprises an inner counter bore  24  that receives the outer surface of the stiffener  20 . The distal shaft  14  and proximal shaft  13  are attached by glue or the like. Other methods for attaching the proximal shaft  13  to the distal shaft  14  can be used in accordance with the invention. 
         [0051]    The stiffening tube  20  is held in place relative to the outer wall  22  at the proximal shaft  13 . In a suitable construction of the proximal shaft  13 , a force is applied to the proximal end of the stiffening tube  20 , which causes the distal end of the stiffening tube  20  to firmly push against the counter bore  24 . While under compression, a first glue joint is made between the stiffening tube  20  and the outer wall  22  by a fast drying glue, e.g. Super Glue™. Thereafter, a second glue joint is formed between the proximal ends of the stiffening tube  20  and outer wall  22  using a slower drying but stronger glue, e.g., polyurethane. 
         [0052]    The depicted catheter includes a mechanism for deflecting the catheter body  12 . In the depicted embodiment, the catheter is adapted for bi-directional deflection with a first puller wire  42  extending into the puller wire lumen  32  and a second puller wire  43  extending into the puller wire lumen  33 . The puller wires  42  and  43  are anchored at their proximal ends in the deflection control handle  16  and anchored at their distal end at or near a distal end of the distal shaft  14 . The puller wires are made of any, suitable metal, such as stainless steel or Nitinol, and are preferably coated with Teflon™ or the like. The coating imparts lubricity to the puller wires. Each puller wire preferably has a diameter ranging from about 0.006 to about 0.010 inches. 
         [0053]    To effectuate deflection along the distal shaft  14 , each puller wire is surrounded by a respective compression coil  44  that extends from the proximal end of the proximal shaft  13  and terminates at or near the proximal end of the distal shaft  14 . Each compression coil  44  is made of any suitable metal, preferably stainless steel. The compression coil  44  is tightly wound on itself to provide flexibility, i.e., bending, but to resist compression. The inner diameter of the compression coil  44  is preferably slightly larger than the diameter of the puller wire. For example, when the puller wire has a diameter of about 0.007 inches, the compression coil preferably has an inner diameter of about 0.008 inches. The Teflon™ coating on the puller wire allows it to slide freely within the compression coil  44 . Along its length, the outer surface of each compression coil  44  is covered by a respective flexible, non-conductive sheath  26  to prevent contact between the compression coils  44  and any other components inside the catheter body  12 . The non-conductive sheath  26  may be made of polyimide tubing. Each compression coil  44  is anchored at its proximal end to the proximal end of the stiffening tube  20  in the proximal shaft  13  by glue (not shown). At its distal end, each compression coil is anchored in the respective puller wire lumen  32  and  33  by glue joint  45 . 
         [0054]    The puller wires are anchored at their distal end to the side of the distal shaft  14 , as shown in  FIG. 4 . In this embodiment, a T-shaped anchor  23  is used for each puller wire. The anchor  23  comprises a short piece of tubular stainless steel  25 , e.g., hypodermic stock, which is fitted over the distal end of each puller wire and crimped to fixedly secure it to the puller wire. The distal end of the tubular stainless steel  25  is fixedly attached, e.g., by welding, to a stainless steel cross-piece  27 , such as stainless steel ribbon or the like. The cross-piece  27  sits in a notch  28  in a wall of the distal shaft  14  that extends into the second lumen  32 . The stainless steel cross-piece  27  is larger than the notch  28  and, therefore, cannot be pulled through the notch. The portion of the notch  28  not filled by the cross-piece  27  is filled with glue  21  or the like, preferably a polyurethane glue, which is harder than the material of the distal shaft  14 . Rough edges, if any, of the cross-piece  27  are polished to provide a smooth, continuous surface with the outer surface of the distal shaft  14 . 
         [0055]    With further reference to  FIG. 2B , within the distal shaft  14 , the puller wires  42  and  43  extend through a respective protective sheath  81 , for example of Teflon™, which prevents the puller wire from cutting into the wall of the distal shaft  14  when the distal shaft is deflected. 
         [0056]    Any other suitable technique for anchoring the puller wires  42  and  43  in the distal shaft  14  can also be used. Alternatively, other means for deflecting the distal region can be provided, such as the deflection mechanism described in U.S. Pat. No. 5,537,686, the disclosure of which is incorporated herein by reference. 
         [0057]    Longitudinal movement of the puller wires relative to the catheter body  12 , which results in deflection of the distal shaft  14 , is accomplished by suitable manipulation of the control handle  16  ( FIG. 1 ). Examples of suitable control handles manipulating a single puller wire for unidirectional deflection are disclosed, for example, in U.S. Pat. No. Re 34,502, U.S. Pat. Nos. 5,897,529 and 6,575,931, the entire disclosures of which are incorporated herein by reference. Suitable control handles manipulating at least two puller wires for bidirectional deflection are described in U.S. Pat. Nos. 6,123,699, 6,171,277, and 6,183,463, the disclosures of which are incorporated herein by reference. 
         [0058]    As shown in  FIGS. 3 ,  3 A and  3 B, a needle electrode assembly  46  is provided. The needle electrode assembly  46  is used to ablate tissue while simultaneously injecting saline or other fluid to conduct the ablation energy and cool the needle electrode, thereby creating a theoretic increase in the effective size of the electrode. The needle electrode assembly  46  is extendable and retractable, and may be moved by manipulation of the needle control handle  17  ( FIG. 1 ), as described further below.  FIG. 3  depicts the needle electrode assembly  46  in an extended position relative to the catheter body  12  as it would be to ablate and/or irradiate tissue. The distal end of the needle electrode assembly  46  may be returned or withdrawn into the central lumen  30  to avoid damage to its distal end and/or injury to the patient, particularly during the time that the catheter is advanced through the vasculature or lungs of a patient&#39;s body and during the time in which the catheter is removed from the body. 
         [0059]    The needle electrode assembly  46  comprises a proximal tubing  53  joined, directly or indirectly, to a generally rigid, electrically-conductive distal tubing or hollow needle  55 , as shown in  FIG. 3 . The generally rigid nature of the needle  55  allows it to pierce tissue in order to increase its effectiveness during ablation. In one embodiment, the needle  55  is formed of Nitinol or stainless steel, and, as illustrated in  FIG. 3 , is preferably formed with a beveled edge  56  at the distal tip of the needle electrode assembly  46  to enhance its ability to pierce tissue. The proximal tubing  53  is preferably more flexible than the needle  55  to allow the proximal tubing to bend as necessary with the flexible proximal shaft  13  of the catheter body  12 , for instance when the catheter is inserted into the vasculature of the body. The proximal tubing  53  of the needle electrode assembly  46  may be made of polyimide or polyether etherketone (PEEK), but may be made of any other suitable biocompatible material, such as plastic or metal. 
         [0060]    The proximal tubing  53  of the needle electrode assembly  46  extends from the needle control handle  17 , through the deflection control handle  16 , through the proximal shaft  13 , and into the lumen  30  of the distal shaft  14 . As shown in  FIG. 3 , the distal end of the proximal tubing  53  and the proximal end of the needle  55  are spaced apart slightly by a discontinuity or gap G so that various components can transition between outside the proximal tubing  53  and inside a lumen of the needle  55 . The proximal tubing  53  and needle  55  are mounted, preferably coaxially, within an outer plastic tube  68 . The outer plastic tube  68  can be glued or otherwise attached to the proximal tubing  53  and needle  55  to form a single structure that, as described below, is longitudinally movable or slidable relative to the catheter body  12 . The outer plastic tube  68  extends through the catheter body  12  with the proximal tubing  53  and protects the needle electrode lead wire  29  and thermocouple wires  63  and  64  which lie and extend between the proximal tubing  53  and outer plastic tube  68 , when the needle electrode assembly  46  is moved relative to the catheter body  12 . The needle electrode lead wire  29  and thermocouple wires  63  and  64  extend out through a hole (not shown) in the outer plastic tube  68  within the deflection control handle  16  and are attached to appropriate connectors, as noted above. 
         [0061]      FIG. 3  shows one arrangement for joining the outer plastic tube  68  to the proximal tubing  53  and needle  55 . Specifically, a small piece of plastic tubing  59 , for example, polyimide tubing, is placed over and bridges the gap G. The tubing  59  is attached to the proximal and distal tubings by polyurethane glue or the like to form a single fluid passage through which saline or other fluid can pass from the lumen of the proximal tubing  53  to the lumen of the needle  55 . The small piece of plastic tubing  59  helps to protect the thermocouple wires  63  and  64  and the needle electrode lead wire  29 . A small, e.g., non-conductive, spacer plug  73  is mounted between the distal tubing  55  and the distal end of the outer plastic tube  68 , and glued in place. The spacer plug  73  prevents bodily fluid from entering into the distal end of the needle electrode assembly  46 . 
         [0062]    In one embodiment, the proximal tubing  53  of the needle electrode assembly  46  has an inner diameter of 0.014 inch and an outer diameter of 0.016 inch. The needle  55  has an inner diameter of 0.015 inch and an outer diameter of 0.018 inch and a length of about 1.0 inch. Further, the distal tubing  55  extends past the distal end of the distal shaft  14  about 10 mm. The small plastic tubing  59  has an inner diameter of 0.022 inch and an outer diameter of 0.024, the outer plastic tube  68  has an inner diameter of 0.025 inch and an outer diameter of 0.035 inch, and the plastic spacer  73  has an inner diameter of 0.017 inch and an outer diameter of 0.024 inch. 
         [0063]    Within the catheter body  12 , the needle electrode assembly  46 , comprising the proximal tubing  53 , needle  55 , spacer  73 , plastic tubing  59  and outer plastic tube  68 , is slidably mounted, preferably coaxially, within a protective tube  47  that lines an inner surface of the lumen  30  and is stationary relative to the catheter body  12 . The protective tube  47 , which is preferably made of polyimide, serves to prevent the needle electrode assembly  46  from buckling during extension and retraction relative to the catheter body  12 . The protective tube  47  additionally serves to provide a fluid-tight seal surrounding the needle electrode assembly  46 . 
         [0064]    Other needle electrode assembly designs are contemplated within the scope of the invention. For example, the needle electrode assembly can comprise a single electrically-conductive tube, such as a Nitinol tube, that extends from the needle control handle  17  to the distal end of the catheter. Such a design is described in U.S. patent application Ser. No. 09/711,648, entitled “Injection Catheter with Needle Electrode,” the disclosure of which is incorporated herein by reference. 
         [0065]    As shown in  FIG. 3 , a needle electrode lead wire  29  is electrically connected at its distal end to the electrically-conductive distal tubing or needle  55  for supplying radio frequency energy or other suitable ablation energy to the needle. The needle electrode lead wire  29  is soldered, welded or otherwise attached to the outside of the needle  55 , but could be attached elsewhere to the needle. The needle electrode lead wire  29  extends generally alongside the proximal tubing  53  and inside of the outer plastic tubing  68 , through the lumen  30  of the tubing  19  of the distal shaft  14  and the central lumen  18  of the proximal shaft  13 . 
         [0066]    A temperature sensor is provided for measuring the temperature of the tissue targeted by the needle electrode assembly  46  before, during or after a procedure. Any conventional temperature sensor, e.g., a thermocouple or thermistor, may be used. In the depicted embodiment, the temperature sensor comprises a thermocouple  62  formed by an enameled wire pair. One wire of the wire pair is a copper wire  63 , e.g., a 46 AWG copper wire. The other wire of the wire pair is a constantan wire  64 , e.g., a 46 AWG constantan wire. The wires  63  and  64  of the wire pair are electrically isolated from each other except at their distal ends, where they are soldered together, covered with a short piece of plastic tubing  65 , e.g., polyimide, and covered with polyurethane. The plastic tubing  65  is then glued or otherwise attached to the inside wall of the needle  55  of the needle electrode assembly  46 , as shown in  FIG. 3 . The wires  63  and  64  extend out the proximal end of the needle  55  and into the gap G to extend generally alongside the lead wire  29  through the lumen  30  of the distal shaft  14 , the lumen  18  of the proximal shaft  13  and into the deflection control handle  16 . Proximal of the control handle  16 , they are attached to an appropriate connector (not shown) connectable to a suitable temperature monitor (not shown). Within the proximal shaft  13  and deflection control handle  16 , the lead wire  29  and thermocouple wires  64  and  64  may through a protective tube (not shown), which may be eliminated if desired. In an alternative embodiment, the copper wire  63  of the thermocouple can also be used as the lead wire for the needle electrode assembly  46 . 
         [0067]    As also shown in  FIGS. 3 ,  3 A and  3 B, extending along with the needle electrode assembly  46  is at least one wave guide, for example, a flexible fiber optic, which extends through the needle control handle  17 , the deflection control handle  16 , the central lumen  18  of the proximal shaft  13  and the lumen  30  of the distal shaft  14 , and into the lumen of the needle  55  of the needle electrode assembly  46  via the gap G. The catheter  10  includes a wave guide bundle  70 , for example, at least two individual wave guides. In the illustrated embodiment, the wave guide bundle includes emitter wave guide  71  and collector wave guides  72  and  75 , although it is understood that the catheter could function suitably with only one emitter wave guide and one collector wave guide, or with a single waveguide adapted to both emit and collect light. The wave guides extend generally alongside one another and may be bound to each other throughout the catheter body  12 . The distal segments of the wave guides inside the needle  55  may be affixed by glue or the like to an inside surface of its lumen. Distal ends of the wave guides are generally coterminous with the distal end of the needle  55  of the needle electrode assembly  46 , and may be similarly beveled as the distal end of the needle  55  for a smooth profile. It is understood that the wave guide bundle  70  may contain any plurality of wave guides depending on desire and need. For example, the plurality may range between about one and six, including one center emitter wave guide and five surrounding collector wave guides or any other combinations. Although the wave guides in illustrated embodiment extend along outside of the proximal tubing  53  through the catheter body  12 , it is understood that they may extend through the lumen of the proximal tubing, if desired or appropriate. 
         [0068]    As shown in  FIGS. 5 and 5A , the emitter wave guide  71  is adapted to deliver light energy to the distal end of the needle  55  which has been inserted into target tissue  102  in the right atrium of a patient&#39;s heart. Light energy  112  exiting the wave guide may become transmitted light energy, light energy absorbed as heat, and/or refracted light energy  118 . Light refracted by tissue back onto the distal ends of the collector wave guides  72  and  75  is collected and transmitted proximally along the catheter body  12  toward the handles  16  and  17 . 
         [0069]    In accordance with a feature of the present invention, the wave guide bundle  70  and the needle  55  are arranged at the distal end of the distal shaft  14  such that they are longitudinally parallel, coextensive and/or coaxial for purposes of having their respective distal ends be adapted for at least targeting, contacting and/or piercing a selected target tissue site. That is, by having the distal ends of the wave guides closely aligned with, inside or surrounding the needle  55 , it is guaranteed that a biopsy location identified and analyzed by the wave guides will be nearly identical to the location ablated by the needle electrode assembly. 
         [0070]    As shown in  FIGS. 2A ,  2 B and  3 , within the catheter body  12 , the needle electrode assembly  46 , electrode lead wire  29 , thermocouple wires  63  and  64 , and wave guide bundle  70  extending through the outer plastic tubing  68 , (collectively referred to herein as the “Outer Plastic Tubing Assembly (OPTA)  68 A,” are slidably housed within the protective tube  47  that is stationary relative to the catheter body  12 . That is, the OPTA  68 A is longitudinally movable or slidable relative to the protective tube  47 . Within the deflection control handle  16 , the protective tube  47  and the OPTA  68 A extend into a protective shaft  66  ( FIG. 1 ), which may be made of polyurethane. 
         [0071]    Longitudinal movement of the OPTA  68 A or at least the needle electrode assembly  46  (and of the wave guide bundle  70  along therewith so they do not break when the needle electrode assembly is extended or retracted) is achieved using the needle control handle  17 . The OPTA  68 A and the protective tubing  47  extend from the deflection control handle  16  to the needle control handle  17  within the protective shaft  66 . 
         [0072]    In the illustrated embodiment of  FIG. 6 , the needle control handle  17  comprises a generally cylindrical outer body  80  having proximal end  80 P and distal end  80 D, a longitudinal piston chamber  82  extending partially therethrough, and a longitudinal needle passage  83  extending partially therethrough. The piston chamber  82  extends from the proximal end  80 P of the outer body  80  partway into the handle  17 , but does not extend out the distal end  80 D of the outer body. The needle passage  83 , which has a diameter less than that of the piston chamber  82 , extends from the distal end of the piston chamber to the distal end  80 D of the outer body  80 . 
         [0073]    A piston  84 , having proximal end  84 P and distal end  84 D, is slidably mounted within the piston chamber  82 . A proximal fitting  86  is mounted in and fixedly attached to the proximal end  84 P of the piston  84 . The proximal fitting  86  includes a tubular distal region  87  that extends distally from the main body of the proximal fitting and into the proximal end  84 P of the piston. The piston  84  has an axial passage  85  which is coaxial and connects with an axial passage  89  formed in the proximal fitting  86 . The OPTA  68 A extends through the axial passages  85  and  89 , as described in more detail below. A compression spring  88  is mounted within the piston chamber  82  between the distal end  84 D of the distal end  84 D of the piston  84  and the distal end of the piston chamber  82 . The compression spring  88  can either be arranged between the piston  84  and outer body  80 , or can have one end in contact with or fixed to the piston  84 , while the other end is in contact with or fixed to the distal end  80 D of the outer body  80 . 
         [0074]    From the deflection control handle  16 , the OPTA  68 A and the protective shaft  66  extend proximally into the distal end of the needle passage  83  of the needle control handle  17 . As shown in  FIG. 6A , within the needle passage  83 , the OPTA  68 A and protective shaft  66  extend into a first metal tube  90 , which may be made of stainless steel. If desired, the first metal tube  90  could instead be made of a rigid plastic material. The first metal tube  90  is secured to the outer body  80  of the needle control handle  17  by a set screw  101  or any other suitable means. The protective shaft  66  terminates at its proximal end within the first metal tube  90 . 
         [0075]    A second metal tube  91  is provided, with its distal end  91 D received, preferably coaxially, inside proximal end  90 P of the first metal tube  90 , with the distal end  91 D abutting the proximal end of the protective shaft  66 . The second metal tube  91  is fixed in place relative to the first metal tube  90  and thus also to the outer body  80  by the set screw  101 . The second metal tube  91 , like the first metal tube  90 , could alternatively be made of a rigid plastic material. As shown in  FIG. 6B , the second metal tube  91  terminates at its proximal end  91 P which is distal of a proximal end of the compression spring  88  in a neutral state and/or the distal end  84 D of the piston  84  in a neutral state. As such, the OPTA  68 A extends through the axial passage  85  of the piston  84 . The first metal tube  90  serves as a protective sheath to guarantee coaxial alignment over the butt connection of the proximal end of the protective shaft  66  and the distal end of the second metal tube  91 . 
         [0076]    Proximal end of the OPTA  68 A is received in the axial passage  89  of the tubular distal end  87  of the proximal fitting  86 . The protective tube  47  terminates at its proximal end in the tubular distal region  87  which exposes proximal end of the OPTA  68 A for fixed attachment by glue or the like to an inner surface of the axial passage  89 . Thus, the piston  84  and the OPTA  68 A are coupled to the proximal fitting  86  for longitudinal movement relative to the second metal tube  91 , the first metal tube  90  and the outer body  80 . Accordingly, when the piston  84  is moved distally (toward the right in  FIG. 6 ) relative to the outer body  80 , the OPTA  68 A is moved distally relative to the catheter body  12  thereby advancing the needle electrode assembly  46  for ablation and/or spectroscopy. 
         [0077]    Within the proximal fitting  86 , the proximal tubing  53  extends out of the outer plastic tube  68  and into a first protective sheath  15  and is connected to a luer connector  65 , which is connected to an irrigation pump or other suitable fluid infusion source  119 , as shown in  FIG. 7 . Similarly, the needle electrode lead wire  29  and the thermocouple wires  63  and  64  extend out of the outer plastic tube  68  and into a second protective sheath  36 , as shown in  FIG. 7 , which is connected to a suitable connector  67 , such as a  10 -pin electrical connector, for connecting the needle electrode lead wire to a source of ablation energy and the thermocouple wires to a suitable monitoring system. The emitter wave guide  71  extends out of the outer plastic tube  68  and into a third protective sheath  35 , as shown in  FIG. 7 , which is connected to a suitable light source, which may be a lamp, light emitting diodes (LEDs), or multiple lasers. The collector wave guides  72  and  75  extend out of the outer plastic tube  88  and into a fourth protective sheath  37 , as shown in  FIG. 7 , which is connected to a suitable light analyzer, e.g., a spectrometer, to process the collected light. 
         [0078]    In use, force is applied to the piston  84  to cause distal movement of the piston relative to the outer body  80 , which compresses the compression spring  88 . This movement causes the OPTA  68 A, inclusive of the needle electrode assembly  46  and the wave guide bundle  70 , to correspondingly move distally relative to the outer body  80 , protective shaft  66 , protective tube  47 , proximal shaft  13 , and distal shaft  14  so that a distal end of the distal tubing  55  of the needle electrode assembly  46  extends outside the distal end of the distal shaft  14 . When the force is removed from the piston  84 , the compression spring  88  expands and pushes the piston proximally to its original position, thus causing the distal end of the distal tubing  55  of the needle electrode assembly  46 , along with the distal ends of the wave guide bundle  70 , to retract back into the distal shaft  14 . Upon distal movement of the piston  84 , the proximal tubing  53  and other plastic tubing  68  move distally into the protective tube  47  to prevent the proximal tubing  53  and the outer plastic tube  68  from buckling within the axial passage  85 . 
         [0079]    The piston  84  further comprises a longitudinal slot  100  extending along a portion of its outer surface. A securing means  102 , such as a set screw, pin, or other locking mechanism, extends radially through the outer body  80  and into the longitudinal slot  100 . This design and the set screw limit the distance that the piston  84  can be slid proximally out of the piston chamber  82 . When the needle electrode assembly  46  is in the retracted position (as shown in  FIG. 6 ), preferably the securing means  102  is at or near the distal end of the longitudinal slot  100 . 
         [0080]    The proximal end of the piston  84  has a threaded outer surface  104 . A circular thumb control  106  is rotatably mounted on the threaded outer surface  104  at proximal end of the piston  84 . The thumb control  106  has a threaded inner surface  108  that interacts with the threaded outer surface  104  of the piston  84  so that the longitudinal position of the thumb control  106  relative to the proximal end  80 P of the outer body  80  is adjustable. The thumb control  106  acts as a stop, limiting the distance that the piston  84  can be pushed distally into the piston chamber  82 , and thus the distance that the needle electrode assembly  46  can be extended out of the distal end of the catheter body  12 . The threaded surfaces of the thumb control  106  and piston  84  allow the thumb control to be moved closer or farther from the proximal end  80 P of the outer body  80  so that the extension distance of the needle electrode assembly  46  can be controlled by the physician. A securing means, such as a tension screw  109  is provided in the thumb control  106  to control the tension between the thumb control and piston  84  for locking and releasing the thumb control in a longitudinal position on the proximal end  84 P of the piston. As would be recognized by one skilled in the art, the thumb control  106  can be replaced by any other mechanism that can act as a stop for limiting the distance that the piston  84  extends into the piston chamber  82 , and it is not necessary, although it is preferred, that the stop be adjustable relative to the piston. 
         [0081]    In the depicted embodiment, as shown in  FIG. 3 , the catheter further includes at least one location sensor  77 . The location sensor  77  is used to determine the coordinates of the distal end of the distal shaft  14 . Specifically, the location sensor  77  is used to monitor the precise location of the distal end of the catheter in the patient&#39;s body. The location sensor  77  is connected to a corresponding sensor cable  74 . The sensor cable  74  extends, along with the lead wire  29 , through the lumen  31  of the distal shaft  14  ( FIG. 2C ), and through the proximal shaft  13  within a protective tube (not shown) and then into the deflection control handle  16  and out of the proximal end of the deflection control handle within an umbilical cord (not shown) to a sensor control module (not shown) that houses a circuit board (not shown). Alternatively, the circuit board can be housed within the control handle  16 , for example, as described in U.S. Pat. No. 6,024,739, the disclosure of which is incorporated herein by reference. The sensor cable  74  comprises multiple wires encased within a plastic covered sheath. In the sensor control module, the wires of the sensor cable  74  are connected to the circuit board. The circuit board amplifies the signal received from the location sensor  77  and transmits it to a computer in a form understandable by the computer by means of a sensor connector at the proximal end of the sensor control module. Also, because the catheter is designed for single use only, the circuit board may contain an EPROM chip that shuts down the circuit board approximately twenty-four hours after the catheter has been used. This prevents the catheter, or at least the location sensor  77 , from being used twice. 
         [0082]    The location sensor  77  may be an electromagnetic location sensor. For example, the location sensor  77  may comprise a magnetic-field-responsive coil, as described in U.S. Pat. No. 5,391,199, or a plurality of such coils, as described in International Publication WO 96/05758. The plurality of coils enables the six-dimensional coordinates (i.e. the three positional and the three orientational coordinates) of the location sensor  77  to be determined. Alternatively, any suitable location sensor known in the art may be used, such as electrical, magnetic or acoustic sensors. Suitable location sensors for use with the present invention are also described, for example, in U.S. Pat. Nos. 5,558,091, 5,443,489, 5,480,422, 5,546,951, and 5,568,809, International Publication Nos. WO 95/02995, WO 97/24983, and WO 98/29033, and U.S. patent application Ser. No. 09/882,125 filed Jun. 15, 2001, entitled “Position Sensor Having Core with High Permeability Material,” the disclosures of which are incorporated herein by reference. 
         [0083]    As shown in  FIGS. 7 and 7A , the catheter  10  may be used with an integrated ablation and spectroscopy system  200 . In the illustrated embodiment, the system includes an RF generator  202 , a patient interface unit  203 , a communication (COM) unit  204 , a location pad  206 , a processor  207 , input device (e.g., keyboard)  211 , and a display  208 . The COM unit  204  provides electronics for ECG, electrogram collection, amplification, filtering and real-time tracing of catheter distal tip. The PIU  203  allows communication with various components of the system  200 , including signal generator, recording devices, etc. The location pad  206  includes magnetic field generators (e.g., coils) and is typically positioned under a patient&#39;s body to generate magnetic fields within the patient&#39;s body. Responsive to these magnetic fields, the location sensor  77  housed in the distal end of the catheter generates electrical signals which are received by the PIU  203  and transmitted to the COM unit  204  and processed by the processor  207  in order to determine the position (location and/or orientation) coordinates of the catheter distal end. The processor  207  uses the coordinates in driving the display  208  to show location and status of the catheter. Other signals from the catheter  10 , for example, tissue electrical activity and temperature, are also transmitted to the COM unit  204  and the processor  207  via the PIU  203  for processing and analysis, including 3-D mapping of the patient&#39;s heart that is shown on the display  208 . This method of position sensing and processing is described in detail, for example, in PCT International Publication WO 96/05768, whose entire disclosure is incorporated herein by reference, and is implemented in the CARTO system produced by Biosense Webster Inc. (Diamond Bar, Calif.). 
         [0084]    For ablation, the RF generator  202  supplies RF ablation energy to the needle electrode assembly  46  of the catheter  10  via the PIU  203 . For spectroscopy, the system  200  further includes a light source  209  which provides incidental light energy to the catheter  10  via the emitter wave guide  71 . Light collected by collector wave guides  72  and  75  are transmitted to a spectrometer  210  which provides representative signals to the processor  207  which processes the signals to determine various parameters and/or characteristics of the target issue illuminated. The system may include a first foot pedal  205 A connected to the PIU  203  to be used for acquiring catheter location points and a second food pedal  205 B connected to the RF generator  202  for activating/deactivating the RF generator  202 . 
         [0085]    To use a catheter of the invention, an electrophysiologist may introduce a guiding sheath and dilator into the patient, as is generally known in the art. A guidewire may also be introduced for a catheter adapted for such use. As shown in  FIG. 5 , the catheter may be introduced to the right atrium (RA) via the inferior vena cava (IVC). To reach the left atrium (LA), the catheter passes through the septum. 
         [0086]    Through the guiding sheath, the entire catheter body  12  can be passed through the patient&#39;s vasculature to the desired location. Once the distal end of the catheter reaches the desired location, e.g., the right atrium RA, the guiding sheath is withdrawn to expose the distal shaft  14 . The thumb control  61  of the control handle  16  may be manipulated as needed to deflect the distal shaft  14  into position. After the distal end of the catheter body  12  is positioned at a target tissue, the thumb control  106  is depressed to advance the piston  84  of the needle control handle  17 . The set screw  102  may be used to releasably lock the piston  84  in selected longitudinal positions relative to the outer body  84  so as to hold the distal end of the needle at particular depths in tissue. As the piston is advanced distally, the OPTA  68 A is advanced distally to deploy and expose the needle  55  past the distal end of the catheter into the target tissue. Light energy is transmitted by the emitter wave guide  71  into the target tissue and light energy scattered back is collected by the collector wave guides  72  and  77 . The collected light is transmitted proximally along the catheter body  12 , through the deflection control handle  16  and the needle control handle  17  and to the spectrometer  210  for analysis. 
         [0087]    RF energy may be applied to the needle electrode assembly  46  to energize the needle  55  for ablation to create a lesion, including a larger lesion than those created by tissue surface electrode contact. Irrigation fluid may also be provided at the ablation site via the fluid source and pump  119  that provides fluid to be transported through the lumens of the proximal tubing  53  and the needle  55 . Advantageously, both spectroscopy and ablation are performed with the use of a single catheter which may remain in situ so that the ablation tissue site is nearly identical to the tissue site of spectroscopy. In that regard, an additional spectroscopic analysis may be performed after ablation to determine whether the ablation was successfully performed. And, if appropriate, an additional ablation procedure may be performed, again with the advantage that the ablation tissue site remains unchanged. Additional spectroscopic analyses and additional ablation procedures may be repeated as many times as needed all at the same tissue site and with the use of a single catheter. 
         [0088]    FIGS.  8  and  8 A- 8 H illustrate a catheter  300  of the present invention, in accordance with another embodiment. As shown in  FIGS. 9 and 9A , the catheter  300  is adapted for use in a patient&#39;s body, including an organ, for example, lungs  305 , where it can assess and treat diseased tissue, including a tumor  302 . As described below, the catheter  300  has structure similar to the aforementioned catheter  10  in many respects with similar components having similar reference numerals, but there are differences and particular adaptations, including those described below. 
         [0089]    The catheter  300  has a proximal shaft  313 , a distal shaft  314 , a distal tip electrode  348 , a ring electrode  349 , and a needle electrode assembly  346 , which includes a proximal tubing  353  and a distal tubing or “needle”  355 . The catheter  300  also includes a deflection control handle  316 , a needle control handle  317  distal of the handle  316 , and an optical fiber connector  318  distal of the handle  317 . 
         [0090]    As shown in  FIGS. 8D and 8H , the proximal shaft  313  comprises a single, central or axial lumen  318  with an outer wall  322  and a stiffening tube  320 . The distal shaft  314  comprises a multi-lumened tubing  319  with at least four lumens  330 ,  331 ,  332  and  333 . The proximal tubing  353  of the needle electrode assembly  346  extends through the lumen  330 . A cable  374  for location sensor  377  extends through the lumen  331 . Puller wire  342  extends through the lumen  332 . A compression coil  344  surrounding the puller wire extends from the deflection control handle  316  and through the proximal shaft  313  and terminates at its distal end located at a distance distal of the proximal shaft  313 , for example, approximately a quarter of the length of the distal shaft  314 . Notably, the illustrated embodiment of catheter  300  has unidirectional deflection, so only one puller wire is provided, although it is understood that for bi-directional deflection, a second puller wire and a respective lumen diametrically opposite to the lumen  332  would be provided. Lead wires  329 T and  329 R for the tip electrode  348  and ring electrode  349 , respectively, extend through the lumen  333 . 
         [0091]    As shown in  FIG. 8D , the proximal tubing  353  of the needle electrode assembly  346  houses wave guide bundle (including emitter waveguide  371  and collector waveguide  373 ), lead wire  329  and thermocouple wire pair  363  and  364  for the needle  355 . These components extend through a single, center lumen of the proximal tubing  353 . Surrounding the proximal tubing  353  along its length is an outer tubing  368  that extends through the needle control handle  317 , the deflection control handle  316 , the proximal shaft  313 , the distal shaft  314  and into the distal tip electrode  348 , in which the distal end of the outer tubing  368  is anchored, as described below. Accordingly, in this embodiment, the outer tubing  368  is longitudinally stationary relative to the catheter, and thus not longitudinally moveable with the proximal tubing  353  and needle  355 , which can be advanced and withdrawn relative to the catheter body  312  and tip electrode  348 . In one embodiment, the outer tubing  368  has an outer layer of polyimide and an inner layer of PTFE, the proximal tubing  353  is constructed of PEEK, and the needle  355  is constructed of nitinol. 
         [0092]    At the distal end of the proximal tubing  353  of the needle electrode assembly  346 , a proximal end of the needle  355  is received in the lumen of the tubing  353  and anchored therein by a lead wire  329 N that extends through the proximal tubing  535 . The lead wire  329 N is coiled around and soldered to a proximal end  355 P of the needle, which is fixed to the distal end of the proximal tubing  353 . The wave guides  370  and  371  and thermocouple wire pair  633  and  634  for the needle  355  also extend through the lumen of the proximal tubing  353  and continue through a single center lumen of the needle  355  where they have distal ends generally coterminous with a beveled distal end of the needle. Accordingly, the needle electrode assembly  346 , comprising the proximal tubing  353 , the needle  355 , along with the wave guides  370  and  371 , the lead wire  329 N and thermocouple wire pair  363  and  364 , has longitudinal movement within the outer tubing  368  and relative to the proximal shaft  313  and the distal shaft  314 . 
         [0093]    With reference to  FIGS. 8B and 8C , the tip electrode  348  is mounted on a distal end of the tubing  319  of the distal shaft  314 . Between the tip electrode and the tubing  319  is a connector tubing  350 , for example, a short section of tubing with a single lumen suitable for housing and allowing reorientation of the wires and/or cables extending from the distal shaft  14  to the tip electrode  348 . A proximal end of the connector tubing  350  receives a distal end of the tubing  319  and a distal end of the connector  350  receives a proximal end of the tip electrode  348 . 
         [0094]    The tip electrode  348  is formed with a longitudinal passage  351  that is axially aligned with the lumen  330  of the distal shaft  314 . The passage  351  has a proximal portion  351 P with a larger diameter and a distal portion  351 D with a smaller diameter. Extending through the proximal portion  351 P is the distal end of the wider outer tubing  368  extending from the lumen  330  of the distal shaft  314  which is fixed in the proximal portion  351 P. Extending through the outer tubing  368  is the proximal tubing  353  of the needle electrode assembly  346 . The proximal tubing  353  has a distal end that is situated between the proximal and distal ends of the connector tubing  318 . 
         [0095]    The distal portion  351 D of the passage  351  receives the needle  355  extending from the proximal tubing  353 . As described above, the needle  355  is mounted in the distal end of the proximal tubing  353  and electrically connected by the lead wire  329 N. Due to the outer diameter difference between the proximal tubing  353  and the needle  355 , a junction J between the distal and proximal portions  351 D and  351 P of the passage  351  in the tip electrode  348  acts as a distal stop limiting the amount of distal advancement afforded to the needle electrode assembly  346  relative to the tip electrode  348 . 
         [0096]    The proximal end of the tip electrode  348  is formed with an outer circumferential notch which is received in the distal end of the connector tubing  318 . The ring electrode  349  is mounted over the connector tubing  318  in the notch. The ring electrode  249  and the distal end of the connector tubing  318  are bonded to the tip electrode  348  in the notch by glue or the like, for example, polyurethane  376 . The lead wire  329 R for the ring electrode and the lead wire  329 T for the tip electrode both pass from the lumen  333  of the distal shaft  314  and through the lumen of the connector tubing  318 . The lead wire  329 R is connected to the ring electrode  349  via a hole formed in the connector tubing  318 , The lead wire  329 T for the tip electrode  348  is soldered in a first blind hole  352  formed in a proximal face of the tip electrode  348 . Also anchored in the first blind hole is the distal end of the puller wire  342  which has a crimped short stainless steel tube  323  that is soldered in the hole  354 . The proximal face is also formed with a second blind hole  353  to receive the sensor  377  anchored therein. The cable  374  for the biosensor passes from the lumen  331  of the distal shaft  314  and through the lumen of the connector tubing  318 . 
         [0097]    Accordingly, the catheter  300  has at least three distinguishable electrode elements, namely, the needle  355 , the tip electrode  348  and the ring electrode  349 , each having its own lead wire for separate and independent selective electrical recording and energization. 
         [0098]      FIGS. 8E and 8F  illustrate an embodiment of a deflection control handle  316  and a needle control handle  317  suitable for use with the catheter  300 . Reference is made to the description herein of the deflection control handle  16  and the needle control handle  17  of  FIG. 1 . Much of the description is applicable to the deflection control handle  316  and the needle control handle  317  of  FIGS. 8E and 8F , where similar components are identified by reference numerals with identical last two digits. As for  FIG. 8G , an optical fiber connector  378  is shown proximal of the needle control handle  317  and connected thereto, for connecting the wave guides  371  and  372  to a light source and a spectrometer ( FIG. 7 ). One or more connectors may be provided to define an isolated path for each wave guide. 
         [0099]    The preceding description has been presented with reference to presently preferred embodiments of the invention. Workers skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structure may be practiced without meaningfully departing from the principal, spirit and scope of this invention. As understood by one of ordinary skill in the art, the drawings are not necessarily to scale. Also, different features of different embodiments may be combined as needed or appropriate. Moreover, the catheters described herein may be adapted to apply various energy forms, including microwave, laser, RF and/or cryogens. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and illustrated in the accompanying drawings, but rather should be read consistent with and as support to the following claims which are to have their fullest and fair scope.