Abstract:
Methods of accessing and ablating abnormal epithelium tissue in an alimentary canal are provided. The methods can include steps of (i) inserting an operative element into an alimentary canal such that the proximate to a portion of the alimentary canal having tissue to be ablated; and (ii) using the operative element to apply cryogenic ablation to a site of abnormal tissue.

Description:
CROSS-REFERENCE  
       [0001]     This application is a continuation application of U.S. patent application Ser. No. 10/963,025, filed Oct. 12, 2004, which is a divisional of U.S. patent application Ser. No. 10/247,153, filed Sep. 19, 2002, now U.S. Pat. No. 6,872,206, which is a divisional of U.S. patent application Ser. No. 09/304,737, filed May 4, 1999, now U.S. Pat. No. 6,464,697, which is a continuation-in-part of U.S. patent application Ser. No. 09/026,296, filed Feb. 19, 1998, now U.S. Pat. No. 6,009,877, which is a continuation-in-part of U.S. patent application Ser. No. 08/731,372, filed Oct. 11, 1996, now U.S. Pat. No. 5,964,755, to which applications we claim priority under 35 USC §120. 
     
    
     FIELD OF THE INVENTION  
       [0002]     In a general sense, the invention is directed to methods for treating interior tissue regions of the body. More specifically, the invention is directed to methods for treating dysfunction in or near the cardia of the stomach.  
       BACKGROUND OF THE INVENTION  
       [0003]     The gastrointestinal tract, also called the alimentary canal, is a long tube through which food is taken into the body and digested. The alimentary canal begins at the mouth, and includes the pharynx, esophagus, stomach, small and large intestines, and rectum. In human beings, this passage is about 30 feet (9 meters) long.  
         [0004]     Small, ring-like muscles, called sphincters, surround portions of the alimentary canal. In a healthy person, these muscles contract or tighten in a coordinated fashion during eating and the ensuing digestive process, to temporarily close off one region of the alimentary canal from another.  
         [0005]     For example, a muscular ring called the lower esophageal sphincter surrounds the opening between the esophagus and the stomach. The lower esophageal sphincter (or LES) is a ring of increased thickness in the circular, smooth-muscle layer of the esophagus. Normally, the lower esophageal sphincter maintains a high-pressure zone between fifteen and thirty mm Hg above intragastric pressures inside the stomach.  
         [0006]     When a person swallows food, muscles of the pharynx push the food into the esophagus. The muscles in the esophagus walls respond with a wavelike contraction called peristalsis. The lower esophageal sphincter relaxes before the esophagus contracts, and allows food to pass through to the stomach. After food passes into the stomach, the lower esophageal sphincter constricts to prevent the contents from regurgitating into the esophagus.  
         [0007]     The stomach muscles churn the food and digestive juices into a mass called chyme. Then the muscles squeeze the chyme toward the pyloric (intestinal) end of the stomach by peristaltic waves, which start at the top of the stomach and move downward. The pyloric sphincter, another ringlike muscle, surrounds the duodenal opening. The pyloric sphincter keeps food in the stomach until it is a liquid. The pyloric sphincter then relaxes and lets some chyme pass into the duodenum.  
         [0008]     Dysfunction of a sphincter in the body can lead to internal damage or disease, discomfort, or otherwise adversely affect the quality of life. For example, if the lower esophageal sphincter fails to function properly, stomach acid may rise back into the esophagus. Unlike the stomach, the esophagus has no natural protection against stomach acids. When the stomach contents make contact with the esophagus, heartburn or other disease symptoms, including damage to the esophagus, can occur.  
         [0009]     Gastrointestinal reflux disease (GERD) is a common disorder, characterized by spontaneous relaxation of the lower esophageal sphincter. It has been estimated that approximately two percent of the adult population suffers from GERD. The incidence of GERD increases markedly after the age of 40, and it is not uncommon for patients experiencing symptoms to wait years before seeking medical treatment.  
         [0010]     GERD is both a normal physiologic phenomenon that occurs in the general population and a pathophysiologic phenomenon that can result in mild to severe symptoms.  
         [0011]     GERD is believed to be caused by a combination of conditions that increase the presence of acid reflux in the esophagus. These conditions include transient LES relaxation, decreased LES resting tone, impaired esophageal clearance, delayed gastric emptying, decreased salivation, and impaired tissue resistance. Since the resting tone of the lower esophageal sphincter is maintained by both myogenic (muscular) and neurogenic (nerve) mechanisms, some believe that aberrant electrical signals in the lower esophageal sphincter or surrounding region of the stomach (called the cardia) can cause the sphincter to spontaneously relax.  
         [0012]     Lifestyle factors can also cause increased risk of reflux. Smoking, large meals, fatty foods, caffeine, pregnancy, obesity, body position, drugs, hormones, and paraplegia may all exacerbate GERD. Also, hiatal hernia frequently accompanies severe GERD. The hernia may increase transient LES relaxation and delay acid clearance due to impaired esophageal emptying. Thus, hiatal hernias may contribute to prolonged acid exposure time following reflux, resulting in GERD symptoms and esophageal damage.  
         [0013]     The excessive reflux experienced by patients with GERD overwhelms their intrinsic mucosal defense mechanisms, resulting in many symptoms. The most common symptom of GERD is heartburn. Besides the discomfort of heartburn, reflux results in symptoms of esophageal inflammation, such as odynophagia (pain on swallowing) and dysphagia (difficult swallowing). The acid reflux may also cause pulmonary symptoms such as coughing, wheezing, asthma, aspiration pneumonia, and interstitial fibrosis; oral symptoms such as tooth enamel decay, gingivitis, halitosis, and waterbrash; throat symptoms such as a soreness, laryngitis, hoarseness, and a globus sensation; and earache.  
         [0014]     Complications of GERD include esophageal erosion, esophageal ulcer, and esophageal stricture; replacement of normal esophageal epithelium with abnormal (Barrett&#39;s) epithelium; and pulmonary aspiration.  
         [0015]     Treatment of GERD includes drug therapy to reduce or block stomach acid secretions. Still, daily drug therapy does not eliminate the root cause of the dysfunction.  
         [0016]     Invasive abdominal surgical intervention has also been tried with success. One procedure, called Nissen fundoplication, entails invasive, open abdominal surgery. The surgeon wraps the gastric fundis about the lower esophagus, to, in effect, create a new “valve.” Less invasive laparoscopic techniques have also been tried to emulate Nissen fundoplication, also with success. Still, all surgical intervention entails making an incision into the abdomen and carry with it the usual risks of abdominal surgery.  
       SUMMARY OF THE INVENTION  
       [0017]     The invention provides improved methods for treating a tissue region at or near the cardia.  
         [0018]     According to one aspect of the invention, the methods deploy an electrode on a support structure in a tissue region at or near the cardia of the stomach. The support structure has a shape that is well suited for deployment in the cardia.  
         [0019]     In one embodiment, the support structure has a proximal region and a distal region. The proximal region is enlarged in comparison to the distal region, to thereby better conform to the funnel shape of the cardia. The electrode is carried by the enlarged proximal surface. The systems and methods advance the electrode in a path to penetrate the tissue region.  
         [0020]     In one embodiment, the systems and methods and couple the electrode to a source of radio frequency energy to ohmically heat tissue and create a lesion in the tissue region. It has been discovered that natural healing of the lesion tightens the cardia and adjoining tissue.  
         [0021]     The proximally enlarged support structure can assume various shapes, e.g., a pear shape, or a disk shape, or a peanut shape. In one embodiment, the support structure is expandable into the desired shape.  
         [0022]     Features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended Claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is an anatomic view of the esophagus and stomach;  
         [0024]      FIG. 2  is a diagrammatic view of a system for treating body sphincters and adjoining tissue regions, which embodies features of the invention;  
         [0025]      FIG. 3  is a perspective view, with portions broken away, of a device usable in association with the system shown in  FIG. 1  having an operative element for contacting tissue shown in a collapsed condition;  
         [0026]      FIG. 4  is a perspective view, with portions broken away, of the device shown in  FIG. 3 , with the operative element shown in an expanded condition;  
         [0027]      FIG. 5  is a perspective view, with portions broken away, of the device shown in  FIG. 3 , with the operative element shown in an expanded condition and the electrodes extended for use;  
         [0028]      FIG. 6  is an enlarged side view of the operative element when collapsed, as also shown in  FIG. 3 ;  
         [0029]      FIG. 7  is an enlarged side view of the operative element when expanded and with the electrodes extended for use, as also shown in  FIG. 5 ;  
         [0030]      FIG. 8  is an enlarged perspective view of an embodiment the operative element, when fully collapsed;  
         [0031]      FIG. 9  is a side view of the deployment of a flexible endoscope through an esophageal introducer into the stomach;  
         [0032]      FIG. 10  is an enlarged view of the endoscope shown in  FIG. 9 , retroflexed for viewing the cardia and lower esophageal sphincter;  
         [0033]      FIG. 11  is a side view of the deployment of the device shown in  FIG. 3  after deployment of the flexible endoscope shown in  FIG. 9 , placing the operative element in the region of the lower esophageal sphincter;  
         [0034]      FIG. 12  is an enlarged view of the operative element shown in  FIG. 11 , when placed in the region of the lower esophageal sphincter;  
         [0035]      FIG. 13  is an enlarged view of the operative element shown in  FIG. 11 , when expanded into contact with muscosal tissue in the region of the lower esophageal sphincter;  
         [0036]      FIG. 14  is an enlarged view of the operative element shown in  FIG. 11 , when expanded into contact with muscosal tissue in the region of the lower esophageal sphincter and with the electrodes extended to create lesions in the smooth muscle ring of the lower esophageal sphincter;  
         [0037]      FIG. 15  is an enlarged view of the operative element shown in  FIG. 11 , when placed in the region of the cardia;  
         [0038]      FIG. 16  is an enlarged view of the operative element shown in  FIG. 11 , when expanded into contact with muscosal tissue in the cardia;  
         [0039]      FIG. 17  is an enlarged view of the operative element shown in  FIG. 11 , when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0040]      FIG. 18  is an enlarged view of the operative element shown in  FIG. 17 , when fully deployed for creating lesions in the cardia;  
         [0041]      FIG. 19  is an enlarged view of the operative element shown in  FIG. 14  or  FIG. 17 , after being used to form lesions and in the process of being removed from the targeted tissue site;  
         [0042]      FIG. 20  is a top view of a targeted tissue region in the cardia, showing a desired pattern of lesions;  
         [0043]      FIG. 21  is a perspective view of a “pear-shaped” operative element intended for deployment in the cardia, shown in a collapsed condition;  
         [0044]      FIG. 22  is a perspective view of the “pear-shaped” shown in  FIG. 21 , shown in an expanded condition with the electrodes extended for use in an antegrade orientation;  
         [0045]      FIG. 23  is an enlarged view of the operative element shown in  FIG. 22 , when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0046]      FIG. 24  is a perspective view of the “pear-shaped” shown in  FIG. 21 , shown in an expanded condition with the electrodes extended for use in a retrograde orientation;  
         [0047]      FIG. 25  is an enlarged view of the operative element shown in  FIG. 24 , when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0048]      FIG. 26  is an enlarged side view a “disk-shaped” operative element intended for deployment in the cardia, when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0049]      FIGS. 27 and 28  are enlarged side views of operative elements having different “peanut” shapes intended for deployment in the cardia, when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0050]      FIG. 29  is an enlarged side view of an operative element expanded into contact with muscosal tissue in the cardia and with “pig-tail” electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0051]      FIG. 30  is an enlarged perspective section view of an electrode having a cylindrical cross section;  
         [0052]      FIG. 31  is an enlarged perspective section view of an electrode having an elliptical cross section to resist twisting;  
         [0053]      FIG. 32  is an enlarged perspective section view of an electrode having a rectilinear cross section to resist twisting;  
         [0054]      FIG. 33  is an enlarged side view of an electrode deployed from an operative element in the region of the lower esophageal sphincter and having a collar to control the depth of tissue penetration;  
         [0055]      FIG. 34  is a side section view of a stationary spine which comprises a portion of an operative element and which carries a movable electrode for creating lesion patterns;  
         [0056]      FIG. 35  is a side section view of a stationary spine which comprises a portion of an operative element and which carries a pair of movable electrodes for creating lesion patterns;  
         [0057]      FIGS. 36 and 37  are enlarged side views of operative elements deployed in the cardia and having movable spines for positioning either multiple electrodes or a single electrode in different positions for creating lesion patterns;  
         [0058]      FIG. 38  is an enlarged side view of an operative element that carries a steerable electrode for creating lesions in body sphincters and adjoining tissue;  
         [0059]      FIG. 39  is an enlarged side view of an operative element carrying surface electrodes for treating abnormal epithelial tissue in the gastrointestinal tract, the operative element being shown in a collapsed condition and deployed in the region of the lower esophageal sphincter;  
         [0060]      FIG. 40  is an enlarged side view of the operative element shown in  FIG. 39  and in an expanded condition contacting the abnormal epithelial tissue for applying ablation energy;  
         [0061]      FIG. 41  is a perspective view of an operative element comprising a mechanically expandable basket shown in a collapsed condition;  
         [0062]     FIG. 42  is a perspective view of the operative element shown in  FIG.41 , with the operative element shown in an expanded condition to extend the electrodes for use;  
         [0063]      FIG. 43  is a side view showing a spine of the basket shown in  FIG. 41  as it is mechanically flexed for penetrating tissue;  
         [0064]      FIG. 44  is a side view of another operative element comprising a mechanically expandable basket shown in an expanded condition with the electrodes extended for use shown;  
         [0065]      FIG. 45  is a side view of the operative element shown in  FIG. 44  in a collapsed condition;  
         [0066]      FIG. 46  is a perspective view of an operative element that is deployed for use over a flexible endoscope, shown in a collapsed condition;  
         [0067]      FIG. 47i s a perspective view of the operative element shown in  FIG. 48  in an expanded condition and with the electrodes extended for use;  
         [0068]      FIG. 48  is an enlarged view of the operative element shown in  FIG. 47 , when expanded into contact with muscosal tissue in the cardia and with the electrodes extended to create lesions in the smooth muscle of the cardia;  
         [0069]      FIG. 49  is an end view of the operative element taken generally along line  49 - 49  in  FIG. 48 , as viewed from the retroflex endoscope over which the operative element is deployed for use;  
         [0070]      FIG. 50  is a perspective view of the operative element of the type shown in  FIG. 47 , deployed over a flexible endoscope, and including a transparent region within the operative element to permit endoscopic viewing from within the operative element;  
         [0071]      FIG. 51  is a perspective view of the operative element shown in  FIG.50 , with the endoscope positioned within the operative element for viewing;  
         [0072]      FIG. 52  is an enlarged view of an operative element comprising a mechanically expandable basket deployed over a flexible endoscope and with the electrodes penetrating the lower esophageal sphincter to create lesions;  
         [0073]      FIG. 53  is a perspective view of an operative element for treating body sphincters and adjoining tissue regions, shown in an expanded condition with eight electrodes extended for use;  
         [0074]      FIG. 54  is a perspective view of an operative element for treating body sphincters and adjoining tissue regions, shown in an expanded condition and four closely spaced electrodes extended for use;  
         [0075]      FIG. 55 a  perspective distal facing view of an operative element for treating body sphincters and adjoining tissue regions, showing a spine structure with cooling and aspiration ports located in the spines;  
         [0076]      FIG. 56 a  perspective proximal facing view of an operative element shown in  FIG.56 ;  
         [0077]      FIG. 57  is a perspective view of a handle for manipulating the operative element shown in  FIGS. 55 and 56 ;  
         [0078]      FIG. 58A  a perspective view of an operative element for treating body sphincters and adjoining tissue regions, shown a spine structure with cooling ports located in the spines and aspiration ports located in an interior lumen;  
         [0079]      FIG. 58B  a perspective view of an operative element for treating body sphincters and adjoining tissue regions, shown a spine structure with an underlying expandable balloon structure having pin hole ports which weep cooling liquid about the electrodes;  
         [0080]      FIG. 59 a  perspective view of an operative element for treating body sphincters and adjoining tissue regions, shown a spine structure with cooling ports located in the spines and an aspiration port located in its distal tip;  
         [0081]      FIG. 60 a  perspective view of the operative element shown in  FIG. 59 , deployed over a guide wire that passes through its distal tip;  
         [0082]      FIG. 61  is a perspective view of a handle for manipulating the operative element over the guide wire, as shown in  FIG. 60 ;  
         [0083]      FIG. 62 a  perspective view of an operative element for treating body sphincters and adjoining tissue regions, deployed through an endoscope;  
         [0084]      FIG. 63  is a perspective view of an extruded tube that, upon further processing, will form an expandable basket structure;  
         [0085]      FIG. 64  is a perspective view of the extruded tube shown in  FIG. 62  with slits formed to create an expandable basket structure;  
         [0086]      FIG. 65  is the expandable basket structure formed after slitting the tube shown in  FIG. 63 ;  
         [0087]      FIG. 66  is a side section view of the esophagus, showing the folds of mucosal tissue;  
         [0088]      FIG. 67  is a perspective view of a device for treating body sphincters and adjoining tissue regions, which applies a vacuum to mucosal tissue to stabilize and present the tissue for the deployment of electrodes delivered by a rotating mechanism;  
         [0089]      FIG. 68  is a section view of the rotating mechanism for deploying electrodes, taken generally along line  68 - 68  in  FIG. 67  with the electrodes withdrawn;  
         [0090]      FIG. 69  is a view of the rotating mechanism shown in  FIG. 68 , with a vacuum applied to muscosal tissue and the electrodes extended;  
         [0091]      FIG. 70  is a perspective view of a device for treating body sphincters and adjoining tissue regions, which applies a vacuum to mucosal tissue to stabilize and present the tissue for the deployment of straight electrodes;  
         [0092]      FIG. 71  is a side section view of the electrode deployment mechanism of the device shown in  FIG. 70 ;  
         [0093]      FIGS. 72A and 72B  are, respectively, left and right perspective views of an integrated device for treating body sphincters and adjoining tissue regions, and having graphical user interface;  
         [0094]      FIG. 73  is a front view of the device shown in  FIGS. 72A and 72B  showing the components of the graphical user interface;  
         [0095]      FIG. 74  is a view of the graphical user interface shown in  FIG. 73  showing the Standby screen before connection of a treatment device;  
         [0096]      FIG. 75  is a view of the graphical user interface shown in  FIG. 73  showing the Standby screen after connection of a treatment device;  
         [0097]      FIG. 76  is a view of the graphical user interface shown in  FIG. 73  showing the Standby screen after connection of a treatment device and after an electrode channel has been disabled by selection;  
         [0098]      FIG. 77  is a view of the graphical user interface shown in  FIG. 73  showing the Ready screen;  
         [0099]      FIG. 78  is a view of the graphical user interface shown in  FIG. 73  showing the Ready screen while priming of cooling liquid takes place;  
         [0100]      FIG. 79  is a view of the graphical user interface shown in  FIG. 73  showing the RF-On screen;  
         [0101]      FIG. 80  is a view of the graphical user interface shown in  FIG. 73  showing the RF-On screen after an electrode channel has been disabled due to an undesired operating condition;  
         [0102]      FIG. 81  is a view of the graphical user interface shown in  FIG. 73  showing the Pause screen;  
         [0103]      FIG. 82  is a schematic view of the control architecture that the integrated device and associated graphical user interface shown in  FIGS. 72A, 72B , and  73  incorporate; and  
         [0104]      FIG. 83  is an anatomic view of the esophagus and stomach, with portions broken away and in section, showing the location of a composite lesion pattern effective in treating GERD. 
     
    
       [0105]     The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0106]     This Specification discloses various catheter-based systems and methods for treating dysfunction of sphincters and adjoining tissue regions in the body. The systems and methods are particularly well suited for treating these dysfunctions in the upper gastrointestinal tract, e.g., in the lower esophageal sphincter and adjacent cardia of the stomach. For this reason, the systems and methods will be described in this context.  
         [0107]     Still, it should be appreciated that the disclosed systems and methods are applicable for use in treating other dysfunctions elsewhere in the body, which are not necessarily sphincter-related. For example, the various aspects of the invention have application in procedures requiring treatment of hemorrhoids, or incontinence, or restoring compliance to or otherwise tightening interior tissue or muscle regions. The systems and methods that embody features of the invention are also adaptable for use with systems and surgical techniques that are not necessarily catheter-based.  
         [0108]     I. Anatomy of the Lower Esophageal Sphincter Region  
         [0109]     As  FIG. 1  shows, the esophagus  10  is a muscular tube that carries food from the mouth to the stomach  12 . The muscles in the walls of the esophagus  10  contract in a wavelike manner, moving the food down to the stomach  12 . The interior wall of the esophagus includes glands that secrete mucus, to aid in the movement of food by providing lubrication. The human esophagus is about twenty-five centimeters long.  
         [0110]     The stomach  12 , located in the upper left hand side of the abdomen, lays between the esophagus  10  and the small intestine  14 . In people and most animals, the stomach  12  is a simple baglike organ. A human being&#39;s stomach is shaped much like a J.  
         [0111]     The average adult stomach can hold a little over one quart (0.95 liter). The stomach  12  serves as a storage place for food. Food in the stomach  12  is discharged slowly into the intestines  14 . The stomach  12  also helps digest food.  
         [0112]     The upper end of the stomach connects with the esophagus  10  at the cardiac notch  16 , at the top of the J-shape. The muscular ring called the lower esophageal sphincter  18  surrounds the opening between the esophagus  10  and the stomach  12 . The funnel-shaped region of the stomach  12  immediately adjacent to the sphincter  18  is called the cardia  20 . The cardia  20  comprises smooth muscle. It is not a sphincter.  
         [0113]     The lower esophageal sphincter  18  relaxes, or opens, to allow swallowed food to enter the stomach  12 . The lower esophageal sphincter  18 , however, is normally closed, to keep the stomach  12  contents from flowing back into the esophagus  10 .  
         [0114]     Another sphincter, called the pyloric sphincter  22 , surrounds the duodenal opening of the stomach  12 . The pyloric sphincter  22  keeps non-liquid food material in the stomach  12  until it is processed into a more flowable, liquid form. The time that the stomach  12  retains food varies. Usually, the stomach  12  empties in three to five hours.  
         [0115]     In a person suffering from GERD, the lower esophageal sphincter  18  is subject to spontaneous relaxation. The sphincter  18  opens independent of the normal swallowing function. Acidic stomach contents surge upward into the esophagus  10 , causing pain, discomfort, and damage the mucosal wall of the esophagus  10 .  
         [0116]     The stomach  12  distends to accommodate various food volumes. Over time, stomach distention can stretch the cardia  20  or otherwise cause loss of compliance in the cardia  20 . Loss of compliance in the cardia  20  can also pull the lower esophageal sphincter  18  open when the stomach  12  is distended, even absent sphincter muscle relaxation. The same undesired results occur: acidic stomach contents can surge upward into the esophagus  10  with the attendant undesired consequences.  
         [0117]     It should be noted that the views of the esophagus and stomach shown in  FIG. 1  and elsewhere in the drawings are not intended to be strictly accurate in an anatomic sense. The drawings show the esophagus and stomach in somewhat diagrammatic form to demonstrate the features of the invention.  
         [0118]     II. Systems for Sphincters or Adjoining Tissue Regions  
         [0119]     A. System Overview  
         [0120]      FIG. 2  shows a system  24  for diagnosing and/or treating dysfunction of the lower esophageal sphincter  18  and/or the adjoining cardia  20  of the stomach  12 .  
         [0121]     The system  24  includes a treatment device  26 . The device  26  includes a handle  28  made, e.g., from molded plastic. The handle  28  carries a flexible catheter tube  30 . The catheter tube  30  can be constructed, for example, using standard flexible, medical grade plastic materials, like vinyl, nylon, poly(ethylene), ionomer, poly(urethane), poly(amide), and poly(ethylene terephthalate). The handle  28  is sized to be conveniently held by a physician, to introduce the catheter tube  30  into the esophagus  10 . The details of using the treatment device  28  will be described later.  
         [0122]     The handle  28  and the catheter tube  30  can form an integrated construction intended for a single use and subsequent disposal as a unit. Alternatively, the handle  28  can comprise a nondisposable component intended for multiple uses. In this arrangement, the catheter tube  30 , and components carried at the end of the catheter tube  30  (as will be described), comprise a disposable assembly, which the physician releasably connects to the handle  28  at time of use and disconnects and discards after use. The catheter tube  30  can, for example, include a male plug connector that couples to a female plug receptacle on the handle  28 .  
         [0123]     The system  24  may include an esophageal introducer  32 . The esophageal introducer  32  is made from a rigid, inert plastic material, e.g., poly(ethylene) or polyvinyl chloride. As will be described later, the introducer  32  aids in the deployment of the catheter tube  30  into the esophagus  10  through the mouth and throat of a patient.  
         [0124]     Alternatively, the catheter tube  30  may be deployed over a guide wire through the patient&#39;s mouth and pharynx, and into the esophagus  10 , without use of an introducer  32 , as will be described later. Still alternatively, the catheter tube  30  may be passed through the patient&#39;s mouth and pharynx, and into the esophagus  10 , without use of either a guide wire or introducer  32 .  
         [0125]     The catheter tube  30  has a distal end  34 , which carries an operative element  36 . The operative element  36  can take different forms and can be used for either therapeutic purposes, or diagnostic purposes, or both.  
         [0126]     The catheter tube  30  can carry a protection sheath  472  (see  FIG. 2 ) for the operative element  36 . The sheath  472  slides along the catheter tube  30  (as indicated by arrows  473  in  FIG. 2 ) between a forward position enclosing the operative element  36  and a rearward position free of the operative element  36 . When in the forward position, the sheath  472  prevents contact between tissue and the operative element  36 , thereby aiding in the deployment and removal of the operative element  36  through the patient&#39;s mouth and pharynx. When in the rearward position, the sheath  472  frees the operative element  36  for use.  
         [0127]     As will be described in greater detail later, the operative element  36  can support, for example, a device for imaging body tissue, such as an endoscope, or an ultrasound transducer. The operative element  36  can also support a device to deliver a drug or therapeutic material to body tissue. The operative element  36  can also support a device for sensing a physiological characteristic in tissue, such as electrical activity, or for transmitting energy to stimulate or form lesions in tissue.  
         [0128]     According to the invention, one function that the operative element  36  shown in the illustrated embodiment performs is to apply energy in a selective fashion to a targeted sphincter or other body region, which, for the purpose of illustration, are identified as the lower esophageal sphincter  18 , or cardia  20 , or both. The applied energy creates one or more lesions, or a prescribed pattern of lesions, below the mucosal surface of the esophagus  10  or cardia  20 . The subsurface lesions are formed in a manner that preserves and protects the mucosal surface against thermal damage.  
         [0129]     It has been discovered that natural healing of the subsurface lesions leads to a physical tightening of the sphincter  18  and/or adjoining cardia  20 . The subsurface lesions can also result in the interruption of aberrant electrical pathways that may cause spontaneous sphincter relaxation. In any event, the treatment can restore normal closure function to the sphincter  18 .  
         [0130]     In this arrangement, the system  24  includes a generator  38  to supply the treatment energy. In the illustrated embodiment, the generator  38  supplies radio frequency energy, e.g., having a frequency in the range of about 400 kHz to about 10 mHz. Of course, other forms of energy can be applied, e.g., coherent or incoherent light; heated or cooled fluid; resistive heating; microwave; ultrasound; a tissue ablation fluid; or cryogenic fluid.  
         [0131]     A cable  40  extending from the proximal end of the handle  28  terminates with an electrical connector  42 . The cable  40  is electrically coupled to the operative element  36 , e.g., by wires that extend through the interior of the handle  28  and catheter tube  30 . The connector  42  plugs into the generator  38 , to convey the generated energy to the operative element  36 .  
         [0132]     The system  24  also includes certain auxiliary processing equipment. In the illustrated embodiment, the processing equipment comprises an external fluid delivery apparatus  44  and an external aspirating apparatus  46 .  
         [0133]     The catheter tube  30  includes one or more interior lumens (not shown) that terminate in fittings  48  and  50 , located on the handle  28 . One fitting  40  connects to the fluid delivery apparatus  44 , to convey processing fluid for discharge by or near the operative element  36 . The other fitting  50  connects to the aspirating apparatus  46 , to convey aspirated material from or near from the operative element  36  for discharge.  
         [0134]     The system  24  also includes a controller  52 . The controller  52 , which preferably includes a central processing unit (CPU), is linked to the generator  38 , the fluid delivery apparatus  44 , and the aspirating apparatus  46 . Alternatively, the aspirating apparatus  46  can comprise a conventional vacuum source typically present in a physician&#39;s suite, which operates continuously, independent of the controller  52 .  
         [0135]     The controller  52  governs the power levels, cycles, and duration that the radio frequency energy is distributed to the operative element  36 , to achieve and maintain power levels appropriate to achieve the desired treatment objectives. In tandem, the controller  52  also governs the delivery of processing fluid and, if desired, the removal of aspirated material.  
         [0136]     The controller  52  includes an input/output (I/O) device  54 . The I/O device  54  allows the physician to input control and processing variables, to enable the controller to generate appropriate command signals. The I/O device  54  also receives real time processing feedback information from one or more sensors associated with the operative element (as will be described later), for processing by the controller  52 , e.g., to govern the application of energy and the delivery of processing fluid. The I/O device  54  also includes a graphical user interface (GUI), to graphically present processing information to the physician for viewing or analysis. Further details regarding the GUI will be provided later.  
         [0137]     B. Operative Elements  
         [0138]     The structure of the operative element  36  can vary. Various representative embodiments will be described.  
         [0139]     (i) Bipolar Devices  
         [0140]     In the embodiment shown in FIGS.  3  to  7 , the operative element  36  comprises a three-dimensional basket  56 . The basket  56  includes one or more spines  58 , and typically includes from four to eight spines  58 , which are assembled together by a distal hub  60  and a proximal base  62 . In  FIG. 3 , the spines  58  are equally circumferentially spaced apart in side-by-side pairs.  
         [0141]     Each spine  58  preferably comprises a flexible tubular body made, e.g. from molded plastic, stainless steel, or nickel titanium alloy. The cross sectional shape of the spines  58  can vary, possessing, e.g., a circular, elliptical, square, or rectilinear shape. In the illustrated embodiment, the spines  58  possess a rectilinear shape to resist twisting. Further examples of specific configurations for the spines  58  will be provided later.  
         [0142]     Each spine  58  can be surrounded by a sleeve  64  (see  FIG. 7 ) that is preferably textured to impart friction. Candidate materials for the sleeve  64  include knitted Dacron7 material and Dacron7 velour.  
         [0143]     Each spine  58  carries an electrode  66  (see  FIGS. 5 and 7 ). In the illustrated embodiment, each electrode  66  is carried within the tubular spine  58  for sliding movement. Each electrode  66  slides from a retracted position, withdrawn in the spine  58  (shown in  FIGS. 3, 4 , and  6 ), and an extended position, extending outward from the spine  58  (see  FIGS. 5 and 7 ) through a hole in the spine  58  and sleeve  64 .  
         [0144]     A push-pull lever  68  on the handle  28  is coupled by one or more interior wires to the sliding electrodes  66 . The lever  68  controls movement electrodes between the retracted position (by pulling rearward on the lever  68 ) and the extended position (by pushing forward on the lever  68 ).  
         [0145]     The electrodes  66  can be formed from various energy transmitting materials. In the illustrated embodiment, for deployment in the esophagus  10  or cardia  20 , the electrodes  66  are formed from nickel titanium. The electrodes  66  can also be formed from stainless steel, e.g., 304 stainless steel, or, as will be described later, a combination of nickel titanium and stainless steel. The electrodes  66  have sufficient distal sharpness and strength to penetrate a desired depth into the smooth muscle of the esophageal or cardia  20  wall. The desired depth can range from about 4 mm to about 5 mm.  
         [0146]     To further facilitate penetration and anchoring in the esophagus  10  or cardia  20 , each electrode  66  is preferably biased with a bend. Movement of the electrode  66  into the spine  58  overcomes the bias and straightens the electrode  66 .  
         [0147]     In the illustrated embodiment (see  FIG. 5 ), each electrode  66  is normally biased with an antegrade bend (i.e., bending toward the proximal base  62  of the basket  56 ). Alternatively, each electrode  66  can be normally biased toward an opposite retrograde bend (i.e., bending toward the distal hub  60  of the basket  58 ).  
         [0148]     As  FIG. 7  shows, an electrical insulating material  70  is coated about the proximal end of each electrode  66 . For deployment in the esophagus  10  or cardia  20 , the length of the material  70  ranges from about 80 to about 120 mm. The insulating material  70  can comprise, e.g., a Polyethylene Terephthalate (PET) material, or a polyimide or polyamide material. For deployment in the esophagus  10  or cardia  20 , each electrode  66  preferably presents an exposed, non-insulated conductive length of about 8 mm, providing an exposed surface area at the distal end of each electrode  66  of preferably about 0.1 mm 2  to 100 cm 2 .  
         [0149]     When the distal end of the electrode  66  penetrating the smooth muscle of the esophageal sphincter  18  or cardia  20  transmits radio frequency energy, the material  70  insulates the mucosal surface of the esophagus  10  or cardia  20  from direct exposure to the radio frequency energy. Thermal damage to the mucosal surface is thereby avoided. As will be described later, the mucosal surface can also be actively cooled during application of radio frequency energy, to further protect the mucosal surface from thermal damage.  
         [0150]     The ratio between exposed and insulated regions on the electrodes  66  affects the impedance of the electrodes  66  during use. Generally speaking, the larger the exposed region is compared to the insulated region, a lower impedance value can be expected, leading to fewer incidences of power shut-offs due to high impedance.  
         [0151]     Of course, a greater or lesser number of spines  58  and/or electrodes  66  can be present, and the geometric array of the spines  58  and electrodes  66  can vary.  
         [0152]     In the embodiment shown in  FIG. 3 , an expandable structure  72  comprising a balloon is located within the basket  56 . The balloon structure  72  can be made, e.g., from a Polyethylene Terephthalate (PET) material, or a polyamide (non-compliant) material, or a radiation cross-linked polyethylene (semi-compliant) material, or a latex material, or a silicone material, or a C-Flex (highly compliant) material. Non-compliant materials offer the advantages of a predictable size and pressure feedback when inflated in contact with tissue. Compliant materials offer the advantages of variable sizes and shape conformance to adjacent tissue geometries.  
         [0153]     The balloon structure  72  presents a normally, generally collapsed condition, as  FIGS. 3 and 6  show). In this condition, the basket  56  is also normally collapsed about the balloon structure  72 , presenting a low profile for deployment into the esophagus  10 .  
         [0154]     To aid in the collapse of the basket  56  (see  FIG. 8 ), one end (hub  60  or base  62 ) of the basket  56  can be arranged to slide longitudinally relative to the other end of the basket  56 , which is accordingly kept stationary. A stylet  74  attached to the slidable end of the basket  56  (which, in  FIG. 8 , is the base  62 ) is controlled, e.g., by a push-pull mechanism on the handle  28 . The stylet  74 , when pulled, serves to move the ends  58  and  60  of the basket  56  apart when the balloon structure  72  is collapsed. A full collapse of the basket  56  is thereby possible (as  FIG. 8  shows) to minimize the overall profile of the basket  56  for passage through the esophagus  10 . The push-pull mechanism can include a lock to hold the stylet  74  stationary, to maintain the basket  56  in the fully collapsed condition during deployment.  
         [0155]     The catheter tube  30  includes an interior lumen, which communicates with the interior of the balloon structure  72 . A fitting  76  (e.g., a syringe-activated check valve) is carried by the handle  28 . The fitting  76  communicates with the lumen. The fitting  76  couples the lumen to a syringe  78  (see  FIGS. 4 and 5 ). The syringe  78  injects fluid under pressure through the lumen into the balloon structure  72 , causing its expansion.  
         [0156]     Expansion of the balloon structure  72  urges the basket  56  to open and expand (as  FIGS. 4, 5 , and  7  show). The force exerted by the balloon structure  72 , when expanded, is sufficient to exert an opening force upon the tissue surrounding the basket  56 . Preferably, for deployment in the esophagus  10  or cardia  20 , the magnitude of the force exerted by the balloon structure  72  is between about 0.01 to 0.5 lbs.  
         [0157]     For deployment in the lower esophageal sphincter  18 , the diameter of the balloon structure  72 , when expanded, can be optimized at about 2 cm to 3 cm. For deployment in the cardia  20 , the diameter of the balloon structure  72 , when expanded, can be optimized at about 4 cm to about 6 cm.  
         [0158]     In the illustrated embodiment, the controller  52  conditions selected pairs of electrodes  66  to operate in a bipolar mode. In this mode, one of the electrodes comprises the transmitter and the other electrode comprises the return for the transmitted energy. The bipolar electrode pairs can comprise adjacent side-by-side electrodes  66  on a given spine, or electrodes  66  spaced more widely apart on different spines.  
         [0159]     In the illustrated embodiment (see  FIG. 7 ), each electrode  66  carries at least one temperature sensor  80 . Each electrode can carry two temperature sensors  80 , one to sense temperature conditions near the exposed distal end of the electrode  66 , and the other to sense temperature conditions in the insulated material  70 . Preferably, the second temperature sensor  80  is located on the corresponding spine  58 , which rests against the muscosal surface when the balloon structure  72  is inflated.  
         [0160]     In use (see FIGS.  9  to  19 ), the patient lies awake in a reclined or semi-reclined position. If used, the physician inserts the esophageal introducer  32  through the throat and partially into the esophagus  10 . The introducer  32  is pre-curved to follow the path from the mouth, through the pharynx, and into the esophagus  10 . The introducer  32  also includes a mouthpiece  82 , on which the patient bites to hold the introducer  32  in position. The introducer  32  provides an open, unobstructed path into the esophagus  10  and prevents spontaneous gag reflexes during the procedure.  
         [0161]     As before explained, the physician need not use the introducer  32 . In this instance, a simple mouthpiece  82 , upon which the patient bites, is used.  
         [0162]     The physician preferably first conducts a diagnostic phase of the procedure, to localize the site to be treated. As  FIGS. 9 and 10  show, a visualization device can be used for this purpose. The visualization device can comprise an endoscope  84 , or other suitable visualizing mechanism, carried at the end of a flexible catheter tube  86 . The catheter tube  86  for the endoscope  84  includes measured markings  88  along its length. The markings  88  indicate the distance between a given location along the catheter tube  86  and the endoscope  84 .  
         [0163]     As  FIGS. 9 and 10  show, the physician passes the catheter tube  86  through the patients mouth and pharynx, and into the esophagus  10 , while visualizing through the endoscope  84 . Relating the alignment of the markings  88  to the mouthpiece  82 , the physician can gauge, in either relative or absolute terms, the distance between the patient&#39;s mouth and the endoscope  84  in the esophagus  10 . When the physician visualizes the desired treatment site (lower esophageal sphincter  18  or cardia  20 ) with the endoscope  84 , the physician records the markings  88  that align with the mouthpiece  82 .  
         [0164]     The physician next begins the treatment phase of the procedure. As  FIGS. 11 and 12  show, the physician passes the catheter tube  30  carrying the operative element  36  through the introducer  32 . For the passage, the expandable balloon structure  72  is in its collapsed condition, and the electrodes  66  are in their retracted position. The physician can keep the endoscope  84  deployed for viewing the deployment of the operative element  36 , either separately deployed in a side-by-side relationship with the catheter tube  30 , or (as will be described later) by deployment through a lumen in the catheter tube  30  or deployment of the structure  72  through a lumen in the endoscope  84  itself. If there is not enough space for side-by-side deployment of the endoscope  84 , the physician deploys the endoscope  84  before and after deployment of the structure  72 .  
         [0165]     In the illustrated embodiment, the catheter tube  30  includes measured markings  90  along its length. The measured markings  90  indicate the distance between a given location along the catheter tube  30  and the operative element  36 . The markings  90  on the catheter tube  30  correspond in spacing and scale with the measured markings along the endoscope catheter tube  86 . The physician can thereby relate the markings  90  on the catheter tube  30  to gauge, in either relative or absolute terms, the location of the operative element  36  inside the esophagus  10 . When the markings  90  indicate that the operative element  36  is at the desired location (earlier visualized by the endoscope  84 ), the physician stops passage of the operative element  36 . The operative element  36  is now located at the site targeted for treatment.  
         [0166]     In  FIG. 12 , the targeted site is shown to be the lower esophageal sphincter  18 . In  FIG. 15 , the targeted site is shown to be the cardia  20  of the stomach  12 .  
         [0167]     Once located at the targeted site, the physician operates the syringe  78  to convey fluid or air into the expandable balloon structure  72 . The structure  72 , and with it, the basket  56 , expand, to make intimate contact with the mucosal surface, either with the sphincter (see  FIG. 13 ) or the cardia  20  ( FIG. 16 ). The expanded balloon structure  72  serves to temporarily dilate the lower esophageal sphincter  18  or cardia  20 , to remove some or all of the folds normally present in the mucosal surface. The expanded balloon structure  72  also places the spines  58  in intimate contact with the mucosal surface.  
         [0168]     The physician pushes forward on the lever  68  to move the electrodes  66  into their extended position. The electrodes  66  pierce and pass through the mucosal tissue into the smooth muscle tissue of the lower esophageal sphincter  18  ( FIG. 14 ) or cardia  20  ( FIGS. 17 and 18 ).  
         [0169]     The physician commands the controller  52  to apply radio frequency energy between the transmitting and receiving electrodes  66  in each pair. The energy can be applied simultaneously by all pairs of electrodes  66 , or in any desired sequence.  
         [0170]     The energy ohmically heats the smooth muscle tissue between the transmitting and return electrodes  66 . The controller  52  samples temperatures sensed by the sensors  80  to control the application of energy. When each electrode  66  in a given pair carries at least one temperature sensor  80 , the controller  52  can average the sensed temperature conditions or select the maximum temperature condition sensed for control purposes.  
         [0171]     The controller  52  processes the sensed temperatures in a feedback loop to control the application of energy. The GUI can also display the sensed temperatures and the applied energy levels. Alternatively, the physician can manually control the energy levels based upon the temperature conditions displayed on the GUI.  
         [0172]     Preferably, for a region of the lower esophageal sphincter  18  or cardia  20 , energy is applied to achieve tissue temperatures in the smooth muscle tissue in the range of 55° C. to 95° C. In this way, lesions can typically be created at depths ranging from one to four millimeters below the muscosal surface. Typical energies range, e.g., between 100 and 1000 joules per electrode pair.  
         [0173]     It is desirable that the lesions possess sufficient volume to evoke tissue-healing processes accompanied by intervention of fibroblasts, myofibroblasts, macrophages, and other cells. The healing processes results in a contraction of tissue about the lesion, to decrease its volume or otherwise alter its biomechanical properties. The healing processes naturally tighten the smooth muscle tissue in the sphincter  18  or cardia  20 . The bipolar nature of the energy path between the electrodes  66  creates, for a given amount of energy, lesions of greater volume than is typically created in a monopolar fashion.  
         [0174]     To create greater lesion density in a given targeted tissue area, it is also desirable to create a pattern of multiple lesions, e.g., in rings along the targeted treatment site in the lower esophageal sphincter  18  or cardia  20 .  
         [0175]     Various lesion patterns  92  can be achieved. A preferred pattern (shown in  FIG. 20  for the cardia  20 ) comprises several rings  94  of lesions  96  about one centimeter apart, each ring  94  comprising at least eight lesions  96 . For example, a preferred pattern  92  comprise six rings  94 , each with eight lesions  96 . In the cardia  20 , as  FIG. 20  shows, the rings  94  are concentrically spaced about the opening funnel of the cardia  20 . In the lower esophageal sphincter  18 , the rings  94  are axially spaced along the esophagus  10 .  
         [0176]     The physician can create a given ring pattern  92  by expanding the balloon structure  72  and extending the electrodes  66  at the targeted treatment site, to form a first set of four lesions. The physician then withdraws the electrodes  66 , collapses the balloon structure  72 , and rotates the catheter tube  30  by a desired amount. The physician then again expands the structure  72  and again extends the electrodes  66 , to achieve a second set of four lesions. The physician repeats this sequence until a desired ring  94  of lesions  96  is formed. Additional rings  94  of lesions  96  can be created by advancing the operative element axially, gauging the ring separation by the markings  90  on the catheter tube  30 .  
         [0177]     Other, more random or eccentric patterns of lesions can be formed to achieve the desired density of lesions within a given targeted site.  
         [0178]     The bipolar operative element  36  can be used in the manner described to treat both the cardia  20  and the lower esophageal sphincter  18  in a single procedure. Alternatively, the operative element  36  can be used in the manner described to treat either the cardia  20  or the lower esophageal sphincter  18  individually.  
         [0179]     In one embodiment, at least one spine  58  (and preferably all spines) includes an interior lumen  98  (see  FIG. 7 ). The fluid delivery apparatus  44  conveys processing fluid F through the lumen  98  for discharge at the treatment site. The processing fluid F can comprise, e.g., saline or sterile water, to cool the mucosal surface while energy is being applied by the electrode  66  to ohmically heat muscle beneath the surface.  
         [0180]     In this arrangement (see  FIG. 5 ), the catheter tube  30  includes a distal tail  100 , which extends beyond the hub  60  of the basket  56 . An interior lumen  102  extends through the tail  100  and the interior of the balloon structure  72  to connect to the fitting  48 . The aspirating apparatus  46  draws aspirated material and the processing fluid through this lumen  102  for discharge. This arrangement provides self-contained aspiration for the operative element  36 .  
         [0181]     In an alternative embodiment suited for treatment of the lower esophageal sphincter  18  outside the stomach  12  (see  FIG. 11 ), the mouth piece  82  of the esophageal introducer  32 , if used, includes an aspiration port  104 . The aspiration apparatus  46  is coupled to this port  104 . In this arrangement, processing fluid introduced at the treatment site is drawn through the introducer  32  surrounding the catheter tube  30  and into the aspiration apparatus  46  for discharge. In this embodiment, the operative element  36  need not include the self contained, interior aspiration lumen  102 .  
         [0182]     (ii) Structures Shaped for the Cardia  
         [0183]     As  FIG. 1  shows, the cardia  20  presents a significantly different topology than the lower esophageal sphincter  18 . First, the surface area of the cardia  20  is larger than the lower esophageal sphincter  18 . Second, the surface area of the cardia  20  expands with distance from the lower esophageal sphincter  18 . The cardia  20  is therefore “funnel” shaped, compared to the more tubular shape of the lower esophageal sphincter  18 .  
         [0184]     The different topologies can be accommodated by using a family of operative elements having different shapes. One such operative element has a size and geometry better suited for deployment in the lower esophageal sphincter  18  than the cardia  20 , if desired). Another such operative element has a larger size and different geometry better suited for deployment in the cardia  20  than the lower esophageal sphincter. However, it is preferred to provide a single operative element that can be effectively deployed in both regions.  
         [0185]     The location and the orientation of optimal, intimate contact between an operative element and the targeted tissue also differ in the cardia  20 , compared to the lower esophageal sphincter  18 . In the lower esophageal sphincter  18 , optimal, intimate contact occurs generally about the mid-region of the operative element, to thereby conform to the generally tubular shape of the sphincter  18 . In the cardia  20 , optimal, intimate contact occurs generally more about the proximal end of operative device, to thereby conform to the funnel shape of the cardia  20 .  
         [0186]     (1) Proximally Enlarged, Shaped Structures  
         [0187]     FIGS.  21  to  23  show an operative element  106  having a shaped geometry and electrode configuration well suited for use in the cardia  20 . The operative element  106  shares many features of the operative element  36  shown in  FIG. 5 , and common reference numbers are thus assigned.  
         [0188]     Like the previously described element  36 , the operative element  106  comprises an array of spines  58  forming a basket  56 , which is carried at the distal end of a catheter tube  30 . Like the previously described element  36 , the operative element  106  includes electrodes  66  on the spines  58  that can be retracted ( FIG. 21 ) or extended ( FIG. 22 ). As illustrated, the electrodes  66  are likewise bent in an antegrade direction.  
         [0189]     Like the previously described element  36 , the operative element  106  includes an inner balloon structure  72  that expands to open the basket  56  and place it in intimate contact with the cardia  20  for extension of the electrodes  66 .  
         [0190]     The balloon structure  72 , when expanded, as shown in  FIG. 22 , possesses a preformed shape achieved e.g., through the use of conventional thermoforming or blow molding techniques. The structure  72  possesses a “pear” shape, being more enlarged at its proximal end than at its distal end. This preformed pear shape presents an enlarged proximal surface for contacting the cardia  20  (see  FIG. 23 ). The preformed pear shape better conforms to the funnel shaped topography of the cardia  20  than a circular shape. The pear shape, when in intimate contact with the cardia  20 , establishes a secure anchor point for the deployment of the electrodes  66 .  
         [0191]     As also shown in  FIGS. 22 and 23 , the electrodes  66  themselves are repositioned to take advantage of the pear shape of the underlying balloon structure  72 . The electrodes  66  are positioned proximally closer to the enlarged proximal base of the structure  72  than to its distal end. As  FIGS. 24 and 25  show, the proximally located electrodes  66  can also be bent in a retrograde bent direction on the pear-shaped element  106 .  
         [0192]     In use (as  FIGS. 23 and 25  show), the physician deploys the operative element  106  into the stomach  12 . The physician expands the element  106  and then pulls rearward on the catheter tube  30 . This places the enlarged proximal base of the structure  106  in contact with the cardia  20 . The physician next extends the electrodes  66  into the cardia  20  and proceeds with the ablation process. Multiple lesion patterns can be created by successive extension and retraction of the electrodes, accompanied by rotation and axial movement of the catheter tube  30  to reposition the structure  106 .  
         [0193]     If enough space is present, the physician can retroflex an endoscope, also deployed in the stomach  12 , to image the cardia  20  as deployment of the electrodes  66  and lesion formation occur. Typically, however, there is not enough space for side-by-side deployment of the endoscope, and the physician views the cardia  20  before and after the lesion groups are formed.  
         [0194]     As  FIGS. 23 and 25  show, the purposeful proximal shaping of the operative element  106  and the proximal location of the antegrade or retrograde electrodes  66  make the operative element  106  well suited for use in the cardia  20 .  
         [0195]     In  FIGS. 22 and 24 , the electrodes  66  are not arranged in bipolar pairs. Instead, for purposes of illustration, the electrodes  66  are shown arranged in singular, spaced apart relation. In this arrangement, the electrodes  66  are intended for monopolar operation. Each electrode  66  serves as a transmitter of energy, and an indifferent patch electrode (not shown) serves as a common return for all electrodes  66 . It should be appreciated, however, the operative element  106  could include bipolar pairs of electrodes  66  as shown in  FIG. 5 , if desired.  
         [0196]     (2) Disk Shaped Expandable Structures  
         [0197]      FIG. 26  shows another operative element  108  shaped for deployment in the cardia  20 . This element  108  shares many features with the element  36  shown in  FIG. 5 , and common reference numbers have also been assigned.  
         [0198]     In  FIG. 26 , the expandable balloon structure  72  within the element  108  has been preformed, e.g., through the use of conventional thermoforming or blow molding techniques, to present a disk or donut shape. The disk shape also provides an enlarged proximal surface for contacting the cardia  20 , to create a secure anchor for the deployment of the electrodes  66 .  
         [0199]     The physician deploys the operative element  108  into the stomach  12 , preferably imaging the cardia  20  as deployment occurs. The physician expands the disk-shaped element  108  and pulls rearward on the catheter tube  30 , to place the element  108  in contact with the cardia  20 . The physician extends the electrodes into the cardia  20  and proceeds with the ablation process. Lesion patterns are formed by successive extension and retraction of the electrodes  66 , accompanied by rotation and axial movement of the catheter tube  30 .  
         [0200]     As  FIG. 26  shows, antegrade bent electrodes  66  are proximally mounted about the disk-shaped expandable element  108 . Retrograde bent electrodes could also be deployed.  
         [0201]     (3) Complex Shaped Structures Providing Multiple Anchor Points  
         [0202]      FIGS. 27 and 28  show another operative element  110  having a geometry well suited for deployment in the cardia  20 . The balloon structure  72  within the element  110  is preformed, e.g., through the use of conventional thermoforming or blow molding techniques, to possess a complex peanut shape. The complex shape provides multiple surface contact regions, both inside and outside the cardia  20 , to anchor the element  110  for deployment of the electrodes  66 .  
         [0203]     In  FIG. 27 , a reduced diameter portion  112  of the expanded structure  72  contacts the lower esophageal sphincter region. A larger diameter main portion  114  of the expanded structure  72  rests in intimate contact against the cardia  20  of the stomach  12 .  
         [0204]     In an alternative peanut shaped configuration (see  FIG. 28 ), the structure  72  includes a first reduced diameter portion  116  to contact the esophagus  10  above the lower esophageal sphincter  18 . The structure  72  includes a second reduced portion  118  to contact the lower esophageal sphincter  18  region of the esophagus  10 . The structure includes a third, larger diameter main portion  120  to rest in intimate contact against the cardia  20  of the stomach  12 .  
         [0205]     The peanut shaped configurations shown in  FIGS. 27 and 28  provide multiple points of support for operative element  110  both inside and outside the stomach  12 , to thereby stabilize the electrodes.  
         [0206]     In  FIGS. 27 and 28 , antegrade bent electrodes  66  are shown deployed in the cardia  20 . Retrograde bent electrodes could also be deployed.  
         [0207]     C. The Electrodes  
         [0208]     (i) Electrode Shapes  
         [0209]     Regardless of the shape of the operative element and its region of deployment in the body, the electrodes  66  can be formed in various sizes and shapes. As  FIG. 30  shows, the electrodes  66  can possess a circular cross sectional shape. However, the electrodes  66  preferably possess a cross section that provides increased resistance to twisting or bending as the electrodes penetrate tissue. For example, the electrodes  66  can possess a rectangular cross section, as  FIG. 32  shows. Alternatively, the electrodes  66  can possess an elliptical cross section, as  FIG. 31  shows. Other cross sections, e.g., conical or pyramidal, can also be used to resist twisting.  
         [0210]     The surface of the electrode  66  can, e.g., be smooth, or textured, or concave, or convex. The preceding description describes electrodes  66  bent in either an antegrade or retrograde direction over an arc of ninety degrees or less. The bend provides a secure anchorage in tissue. Retraction of the electrodes  66  into the spines  58  overcomes the bias and straightens the electrode  66  when not in use.  
         [0211]     In  FIG. 29 , the electrode  66  is biased toward a “pig-tail” bend, which spans an arc of greater than ninety degrees. The increased arc of the bend enhances the tissue-gripping force, thereby providing a more secure anchorage in tissue. As before, retraction of the electrodes  66  into the spines  58  overcomes the bias and straightens the electrode  66  when not in use.  
         [0212]     A given electrode  66  can comprise a hybrid of materials, e.g., stainless steel for the proximal portion and nickel titanium alloy for the distal portion. The nickel titanium alloy performs best in a curved region of the electrode  66 , due to its super-elastic properties. The use of stainless steel in the proximal portion can reduce cost, by minimizing the amount of nickel titanium alloy required.  
         [0213]     The different materials may be joined, e.g., by crimping, swaging, soldering, welding, or adhesive bonding, which provide electrical continuity between or among the various materials.  
         [0214]     One or both of the materials may be flattened to an oval geometry and keyed together to prevent mutual twisting. In a preferred embodiment, the proximal portion comprises an oval stainless steel tube, into which a distal curved region having a round cross section and made of nickel titanium is slipped and keyed to prevent mutual twisting.  
         [0215]     (ii) Electrode Penetration Depth  
         [0216]     The depth of electrode penetration can also be controlled, to prevent puncture through the targeted tissue region.  
         [0217]     In one embodiment, the push-pull lever  68  on the handle  28 , which controls movement electrodes  66 , can include a ratchet  118  or detent mechanism (see  FIG. 3 ) that provides a tactile indication of electrode advancement. For each click of the ratchet mechanism  118  as the lever  68  is moved forward or rearward, the physician knows that the electrodes have traveled a set distance, e.g., 1 mm.  
         [0218]     Alternatively, or in combination, the electrode  66  can carry a limit collar  121  (see  FIG. 33 ). The limit collar  121  contacts surface tissue when a set maximum desired depth of electrode penetration has been reached. The contact between the collar  121  and surface tissue resists further advancement of the electrode  66 . The physician senses the contact between the collar  121  and surface tissue by the increased resistance to movement of the lever  68 . The physician thereby knows that the maximum desired depth of tissue penetration has been reached and to extend the electrodes  66  no further.  
         [0219]     An electrical measurement can also be made to determine penetration of an electrode  66  in tissue. For example, by applying electrical energy at a frequency (e.g., 5 kHz) less than that applied for lesion formation, impedance of a given electrode  66  can be assessed. The magnitude of the impedance varies with the existence of tissue penetration and the depth of tissue penetration. A high impedance value indicates the lack of tissue penetration. The impedance value is lowered to the extent the electrode penetrates the tissue.  
         [0220]     (iii) Movement of Electrodes  
         [0221]     As before described, it is desirable to be able to create a pattern of multiple lesions to create greater lesion density. The previous discussions in this regard were directed to achieving these patterns by successive extension and retraction of the electrodes  66 , accompanied by rotation and axial movement of the catheter tube  30 .  
         [0222]     An alternative embodiment is shown in  FIG. 34 , which achieves creation of lesion patterns movement without axial and, if desired, rotational movement of the catheter tube  30 . In this embodiment, the basket  56  has an array of spines  58 , as generally shown, e.g., in  FIG. 22  or  24 . As  FIG. 34  shows, each spine  58  in the alternative embodiment includes an inner carrier  122  mounted for axial sliding movement within a concentric outer sleeve  124 . In this arrangement, a push-pull stylet  126  controlled by another lever on the handle (not shown) axially moves the carrier  122  within the outer sleeve  124  (as shown by arrows  125  in  FIG. 34 ).  
         [0223]     A tissue penetrating electrode  66  of the type already described is supported by the carrier  122 . The electrode  66  can be moved by the operator (using the handle-mounted lever  68 , as shown in  FIG. 5 ) from a retracted position within the carrier  122  and an extended position, projecting from a guide hole  128  in the carrier  122  (which  FIG. 34  shows). When in the extended position, the electrode  66  also projects through a window  130  in the outer sleeve  124  for tissue penetration. The window  130  has a greater axial length than the guide hole  128 . The extended electrode  66  can thereby be moved by moving the carrier  122  (as shown by arrows  127  in  FIG. 34 ) and thereby positioned in a range of positions within the window  130 .  
         [0224]     For example, in use, the physician moves the carrier  122  so that the guide hole  128  is aligned with the leading edge of the window  130 . The push-pull stylet  126  can be controlled, e.g., with a detent mechanism that stops forward advancement or otherwise gives a tactile indication when this alignment occurs. External markings on the handle can also visually provide this information. The physician moves the electrodes  66  into their respective extended position, to penetrate tissue. After energy sufficient to form a first ring pattern of lesions is applied, the physician withdraws the electrodes  66  into the carriers  122 .  
         [0225]     The physician now moves the electrodes  66  axially rearward, without moving the catheter tube  30 , by pulling the push-pull stylet  126  rearward. If desired, the physician can rotate the catheter tube  30  to achieve a different circumferential alignment of electrodes  66 . The detent mechanism or the like can click or provide another tactile indication that the guide hole  128  in each spine is aligned with a mid portion of the respective window  130 . Markings on the handle can also provide a visual indication of this alignment. The physician extends the electrodes  66  through the window  130 . This time, the electrodes  66  penetrate tissue in a position axially spaced from the first ring of penetration. Energy is applied sufficient to form a second ring pattern of lesions, which likewise are axially spaced from the first ring. The physician withdraws the electrodes  66  into the carriers.  
         [0226]     The physician can now move the carriers  122  to move the guide holes  128  to a third position at the trailing edge of each window  130 , still without axially moving the catheter tube  30 . The catheter tube  30  can be rotated, if desired, to achieve a different circumferential orientation. The physician repeats the above-described electrode deployment steps to form a third ring pattern of lesions. The physician withdraws the electrodes  66  into the carriers  122  and withdraws the basket  56 , completing the procedure.  
         [0227]     As  FIG. 35  shows, each carrier  122  can hold more than one electrode  66 . In this arrangement, the electrodes  66  on each carrier  122  are extendable and retractable through axially spaced-apart guide holes  128  in the carrier  122 . In this arrangement, the outer sleeve  124  includes multiple windows  130  registering with the electrode guide holes  128 . In this arrangement, the physician is able to simultaneously create multiple ring patterns. Further, the physician can axially shift the electrodes  66  and create additional ring patterns by shifting the carrier  122 , and without axial movement of the catheter tube  30 .  
         [0228]     In the foregoing descriptions, each spine  58  comprises a stationary part of the basket  56 . As  FIGS. 36 and 37  show, an array of movable spines  132 , not joined to a common distal hub, can be deployed along the expandable balloon structure  72 . In  FIGS. 36 and 37 , the expandable structure  72  is shown to have a disk-shaped geometry and is deployed in the cardia  20  of the stomach  12 . Two movable spines  132  are shown for the purpose of illustration, but it should be appreciated that fewer or greater number of movable spines  132  could be deployed.  
         [0229]     In this embodiment, the proximal ends of the spines  132  are coupled, e.g., to a push-pull stylet on the handle (not shown). Under control of the physician, the spines  132  are advanced to a desired position along the structure  72  in the tissue contact region, as shown by arrows  133  in  FIGS. 36 and 37 . Each movable spine  132  can carry a single electrode  66  (as  FIG. 37  shows) or multiple electrodes  66  (as shown in  FIG. 36 ). Regardless, each electrode  66  can be extended and retracted relative to the movable spine  132 .  
         [0230]     In use, the physician positions the movable spines  132  and deploys the electrode  66  or electrodes to create a first lesion pattern in the contact region. By retracting the electrode  66  or electrodes, the physician can relocate the movable spines  132  to one or more other positions (with or without rotating the catheter tube  30 ). By deploying the electrode  66  or electrodes in the different positions by moving the spines  132 , the physician can form complex lesion patterns in the tissue contact region without axial movement of the catheter tube  30 .  
         [0231]     In yet another alternative embodiment (see  FIG. 38 ), an operative element  134  can comprise a catheter tube  30  that carries at its distal end a single mono-polar electrode  66  (or a bipolar pair of electrodes), absent an associated expandable structure. The distal end of the catheter tube  30  includes a conventional catheter steering mechanism  135  to move the electrode  66  (or electrodes) into penetrating contact with a desired tissue region, as arrows  137  in  FIG. 38  show). The electrode  66  can carry a limit collar  121  (as also shown in  FIG. 33 ) to resist advancement of the electrode  66  beyond a desired penetration depth. Using the operative element  134  shown in  FIG. 38 , the physician forms a desired pattern of lesions by making a succession of individual mono-polar or bipolar lesions.  
         [0232]     (iv) Drug Delivery Through Electrodes  
         [0233]     A given electrode  66  deployed by an operative device in a sphincter or other body region can also be used to deliver drugs independent of or as an adjunct to lesion formation. In this arrangement, the electrode  66  includes an interior lumen  136  (as  FIG. 35  demonstrates for the purpose of illustration).  
         [0234]     As before explained, a submucosal lesion can be formed by injecting an ablation chemical through the lumen  136 , instead of or in combination with the application of ablation energy by the electrode.  
         [0235]     Any electrode  66  possessing the lumen  136  can also be used to deliver drugs to the targeted tissue site. For example, tissue growth factors, fibrosis inducers, fibroblast growth factors, or sclerosants can be injected through the electrode lumen  136 , either without or as an adjunct to the application of energy to ablate the tissue. Tissue bulking of a sphincter region can also be achieved by the injection of collagen, dermis, cadaver allograft material, or PTFE pellets through the electrode lumen  136 . If desired, radio frequency energy can be applied to the injected bulking material to change its physical characteristics, e.g., to expand or harden the bulking material, to achieve a desired effect.  
         [0236]     As another example, the failure of a ring of muscle, e.g., the anal sphincter or the lower esophageal sphincter  18 , called achalasia, can also be treated using an electrode  66  having an interior lumen  136 , carried by an operative device previously described. In this arrangement, the electrode  66  is deployed and extended into the dysfunctional sphincter muscle. A selected exotoxin, e.g., serotype A of the Botulinum toxin, can be injected through the electrode lumen  136  to produce a flaccid paralysis of the dysfunctional sphincter muscle.  
         [0237]     For the treatment of achalasia of a given sphincter, the electrode  66  carried by an operative device can also be conditioned to apply stimulant energy to nerve tissue coupled to the dysfunctional muscle. The stimulant energy provides an observable positive result (e.g., a relaxation of the sphincter) when targeted nerve tissue is in the tissue region occupied by the electrode  66 . The observable positive result indicates that position of the electrode  66  should be maintained while applying ablation energy to the nerve tissue. Application of the nerve ablation energy can permanently eliminate the function of a targeted nerve branch, to thereby inactivate a selected sphincter muscle. Further details of the application of ablation energy to nerve tissue can be found in co-pending application entitled “Systems And Methods For Ablating Discrete Motor Nerve Regions.” 
         [0238]     (v) Surface Electrodes  
         [0239]     As earlier mentioned, one of the complications of GERD is the replacement of normal esophageal epithelium with abnormal (Barrett&#39;s) epithelium.  FIGS. 39 and 40  show an operative element  138  for the treatment of this condition.  
         [0240]     The operative element  138  includes an expandable balloon structure  140  carried at the distal end of a catheter tube  30 .  FIG. 39  shows the structure  140  deployed in a collapsed condition in the lower esophageal sphincter  18 , where the abnormal epithelium tissue condition forms.  FIG. 40  shows the structure  140  in an expanded condition, contacting the abnormal epithelium tissue.  
         [0241]     The structure  140  carries an array of surface electrodes  142 . In the illustrated embodiment, the surface electrodes  142  are carried by an electrically conductive wire  144 , e.g., made from nickel-titanium alloy material. The wire  144  extends from the distal end of the catheter tube  30  and wraps about the structure  140  in a helical pattern. The electrodes  142  are electrically coupled to the wire  144 , e.g., by solder or adhesive. Alternatively, the balloon structure  140  can have painted, coated, or otherwise deposited on it solid state circuitry to provide the electrical path and electrodes.  
         [0242]     Expansion of the balloon structure  140  places the surface electrodes  142  in contact with the abnormal epithelium. The application of radio frequency energy ohmically heats the tissue surface, causing necrosis of the abnormal epithelium. The desired effect is the ablation of the mucosal surface layer (about 1 mm to 1.5 mm), without substantial ablation of underlying tissue. The structure  140  is then collapsed, and the operative element  138  is removed.  
         [0243]     Absent chronic exposure to stomach  12  acid due to continued spontaneous relaxation of the lower esophageal sphincter  18 , subsequent healing of the necrosed surface tissue will restore a normal esophageal epithelium.  
         [0244]     D. Electrode Structures to Minimize Lesion Overlap  
         [0245]     As before described, it is desirable to create one or more symmetric rings of lesions with enough total volume to sufficiently shrink the lower esophageal sphincter or cardia.  
         [0246]      FIG. 83  shows a lesion pattern  500  that has demonstrated efficacy in treating GERD. The lesion pattern  500  begins at the Z-line  502 , which marks the transition between esophageal tissue (which is generally white in color) and stomach tissue (which is generally pink in color). The tissue color change at or near the Z-line  502  can be readily visualized using an endoscope.  
         [0247]     The lower esophageal sphincter  18  (which is about 4 cm to 5 cm in length) extends above and below the Z-line  502 . The Z-line  502  marks the high pressure zone of the lower esophageal sphincter  18 . In the region of the Z-line  502 , the physician may encounter an overlap of sphincter muscle and cardia muscle.  
         [0248]     As  FIG. 83  shows, the lesion pattern  500  extends about 2 cm to 3 cm from the Z-line  502  into the cardia  20 . The pattern  500  comprises a high density of lesion rings  504 , spaced apart by about  5  mm, with from four to sixteen lesions in each ring  504 . Five rings  504 ( 1 ) to  504 ( 5 ) are shown in  FIG. 83 . The uppermost ring  504 ( 1 ) (at or near the Z-line  502 ) contains eight lesions. The next three rings  504 ( 2 ) to  504 ( 4 ) each contains twelve lesions. The lower most ring  504 ( 5 ) contains eight lesions.  
         [0249]     The lesion pattern  500  formed in this transition region below the Z-line  502  creates, upon healing, an overall desired tightening of the sphincter  18  and adjoining cardia  20  muscle, restoring a normal closure function.  
         [0250]     It is also believed that the pattern  500  formed in this transition region may also create a neurophysiologic effect, as well. The lesion pattern  500  may interrupt infra- and supra-sphincter nerve conduction. The nerve pathway block formed by the lesion pattern  500  may mediate pain due to high pH conditions that accompany GERD and may in other ways contribute to the overall reduction of spontaneous sphincter relaxation that the procedure provides.  
         [0251]     As before described, rotation or sequential movement of electrodes  66  can achieve the desired complex lesion pattern  500 . However, in sequentially placing the lesions, overlapping lesions can occur.  
         [0252]     There are various ways to minimize the incidence of lesion overlap.  
         [0253]     (i) Full Ring Electrode Structures  
         [0254]     To prevent overlapping lesions, the operative element  36  can, e.g., carry a number of electrodes  66  sufficient to form all the desired lesions in a given circumferential ring with a single deployment. For example, as  FIG. 53  illustrates, when the desired number of lesions for a given ring is eight, the operative element  36  carries eight electrodes  66 . In this arrangement, the electrodes  66  are equally spaced about the circumference of the balloon structure  72  on eight spines  58 . As before described, each spine  58  preferably includes an interior lumen with a port  98  to convey a cooling liquid like sterile water into contact with the mucosal surface of the targeted tissue site.  
         [0255]     The generator  38  can include eight channels to supply treatment energy simultaneously to the eight electrodes  66 . However, the generator  38  that supplies treatment energy simultaneously in four channels to four electrodes  66  shown, e.g., in  FIG. 22 , can be readily configured by the controller  52  to supply treatment energy to the eight electrodes  66  shown in  FIG. 53 .  
         [0256]     (1) Monopolar/Hottest Temperature Control  
         [0257]     In one configuration, pairs of electrodes  66  are shorted together, so that each channel simultaneously powers two electrodes in a monopolar mode. For simplicity, the shorted electrodes  66  are preferably located on, adjacent spines  58 , but an adjacent relationship for shorted electrodes is not essential.  
         [0258]     Each electrode  66  carries a temperature sensor  80 , coupled to the I/O device  54  of the controller  52 , as previously described. The controller  52  alternatively samples the temperature sensed by the sensors  80  for each shorted pair of electrodes  66 . The controller  52  selects the hottest sensed temperature to serve as the input to control the magnitude of power to both electrodes. Both electrodes receive the same magnitude of power, as they are shorted together.  
         [0259]     (2) Monopolar/Average Temperature Control  
         [0260]     In one configuration, pairs of electrodes  66  are shorted together, as described in the previous configuration, so that each channel simultaneously powers two electrodes in a monopolar mode.  
         [0261]     Each electrode  66  carries a temperature sensor  80  and are coupled to the I/O device  54  of the controller  52 . In this configuration, the temperature sensors  80  for each shorted pair of electrodes  66  are connected in parallel. The controller  52  thus receives as input a temperature that is approximately the average of the temperatures sensed by the sensors  80  for each shorted pair of electrodes  66 . The controller  52  can include an algorithm to process the input to achieve a weighted average. The controller  52  uses this approximate average to control the magnitude of power to both electrodes. As previously stated, both electrodes receive the same magnitude of power, as they are shorted together.  
         [0262]     (3) Monopolar/Switched Control  
         [0263]     In this configuration, the controller  52  includes a switch element, which is coupled to each electrode  66  and its associated temperature sensor  80  independently. In one position, the switch element couples the four channels of the generator  38  to four of the electrodes (Electrode Group A). In another position, the switch element couples the four channels of the generator  38  to another four of the electrodes (Electrode Group B).  
         [0264]     The electrodes of Group A could be located on one side of the element  36 , and the electrodes of Group B could be located on the opposite side of the element  36 . Alternatively, the electrodes  66  of Groups A and B can be intermingled about the element  36 .  
         [0265]     The switch element can switch between Electrode Group A and Electrode Group B, either manually or automatically. The switching can occur sequentially or in a rapidly interspersed fashion.  
         [0266]     In a sequential mode, Electrode Group A is selected, and the controller samples the temperatures sensed by each sensor  80  and individually controls power to the associated electrode  66  based upon the sensed temperature. As tissue heating effects occur as a result of the application of energy by Electrode Group A, the other Electrode Group B is selected. The controller samples the temperatures sensed by each sensor  80  and individually controls power to the associated electrode  66  based upon the sensed temperature. As tissue heating effects occur as a result of the application of energy by Electrode Group B, the other Electrode Group A is selected, and so on. This mode may minimize overheating effects for a given electrode group.  
         [0267]     In an interspersed fashion, the switching between Electrode Groups A and B occurs at greater time intervals between the application of energy, allowing tissue moisture to return to desiccated tissue between applications of energy.  
         [0268]     (4) Bipolar Control  
         [0269]     In this configuration, the controller  52  conditions four electrodes  66  to be transmitters (i.e., coupled to the four channels of the generator  38 ) and conditions the other four electrodes to be returns (i.e., coupled to the energy return of the generator  38 ). For simplicity, the transmitter and return electrodes are preferably located on adjacent spines  58 , but this is not essential.  
         [0270]     In one arrangement, the four returns can be independent, with no common ground, so that each channel is a true, independent bipolar circuit. In another arrangement, the four returns are shorted to provide a single, common return.  
         [0271]     For each bipolar channel, the controller  52  samples temperatures sensed by the sensors  80  carried by each electrode  66 . The controller  52  can average the sensed temperature conditions by each electrode pair. The controller  52  can include an algorithm to process the input to achieve a weighted average. Alternatively, the controller  52  can select the maximum temperature condition sensed by each electrode pair for control purposes.  
         [0272]     The electrodes  66  used as return-electrodes can be larger than the electrodes  66  used to transmit the energy. In this arrangement, the return electrodes need not carry temperature sensors, as the hottest temperature will occur at the smaller energy transmitting electrode.  
         [0273]     (ii) Partial Ring Electrode Structures  
         [0274]     To prevent overlapping lesions, the operative element  36  can, e.g., carry a number of electrodes  66  sufficient to form, in a single deployment, a partial arcuate segment of the full circumferential ring. For example, as  FIG. 54  illustrates, when the desired number of lesions for a given ring is eight, the operative element  36  carries four electrodes  66  in a closely spaced pattern spanning 135 degrees on four spines  58 .  
         [0275]     In use, the physician deploys the element  36  and creates four lesions in a partial arcuate segment comprising half of the full circumferential ring. The physician then rotates the element  36  one-hundred and eighty degrees and creates four lesions in a partial arcuate segment that comprises the other half of the full circumferential ring.  
         [0276]     The physician may find that there is less chance of overlapping lesions by sequentially placing four lesions at 180 intervals, than placing four lesions at 90 degree intervals, as previously described.  
         [0277]     E. Mechanically Expandable Electrode Structures  
         [0278]      FIGS. 41 and 42  show an operative element  146  suited for deployment in the lower esophageal sphincter  18 , cardia  20 , and other areas of the body.  
         [0279]     In this embodiment, the operative element  146  comprises an expandable, three-dimensional, mechanical basket  148 . As illustrated, the basket  148  includes eight jointed spines  150 , although the number of spines  158  can, of course, vary. The jointed spines  150  are pivotally carried between a distal hub  152  and a proximal base  154 .  
         [0280]     Each jointed spine  150  comprises a body made from inert wire or plastic material. Elastic memory material such as nickel titanium (commercially available as NITINOLJ material) can be used, as can resilient injection molded plastic or stainless steel. In the illustrated embodiment, the jointed spines  150  possess a rectilinear cross sectional shape. However, the cross sectional shape of the spines  150  can vary.  
         [0281]     Each jointed spine  150  includes a distal portion  158  and a proximal portion  160  joined by a flexible joint  156 . The distal and proximal portions  158  and  160  flex about the joint  156 . In the illustrated embodiment, the spine portions  158  and  160  and joint  156  are integrally formed by molding. In this arrangement, the joint  156  comprises a living hinge. Of course, the spine portions  158  and  160  can be separately manufactured and joined by a mechanical hinge.  
         [0282]     In the illustrated embodiment, a pull wire  162  is attached to the distal hub  152  of the basket  148 . Pulling on the wire  162  (e.g., by means of a suitable push-pull control on a handle at the proximal end of the catheter tube  30 ) draws the hub  152  toward the base  154 . Alternatively, a push wire joined to the base  154  can advance the base  154  toward the hub  152 . In either case, movement of the base  154  and hub  152  toward each other causes the spines  150  to flex outward about the joints  156  (as  FIG. 42  shows). The basket  148  opens, and its maximum diameter expands.  
         [0283]     Conversely, movement of the base  154  and hub  152  away from each other causes the spines  150  to flex inward about the joints  156 . The basket  148  closes (as  FIG. 41  shows), and its maximum diameter decreases until it assumes a fully collapsed condition.  
         [0284]     Each joint  156  carries an electrode  166 . The electrode  166  can comprise an integrally molded part of the spine  150 , or it can comprise a separate component that is attached, e.g. by solder or adhesive, to the spine  150 . The electrode material can also be deposited or coated upon the spine  150 .  
         [0285]     When the basket  148  is closed, the electrodes  166  nest within the joints  156  in a lay flat condition (as  FIG. 41  shows), essentially coplanar with the distal and proximal portions  158  and  160  of the spines  150 . As best shown in  FIG. 43 , as the basket  148  opens, flexure of the spines  150  about the joints  156  progressively swings the electrodes  166  outward into a position for penetrating tissue (designated T in  FIG. 43 ).  
         [0286]     As  FIG. 43  shows, flexure of a given spine  150  about the associated joint  156  swings the electrode  166  in a path, in which the angle of orientation of the electrode  166  relative to the spine progressively increases. As the basket  148  opens, the electrode  166  and the distal portion  158  of the spine  150  become generally aligned in the same plane. Further expansion increases the radial distance between the basket axis  164  and distal tip of the electrode  166  (thereby causing tissue penetration), without significantly increasing the swing angle between the basket axis  164  and the electrode  166  (thereby preventing tissue tear). During the final stages of basket expansion, the electrode  166  moves in virtually a linear path into tissue. It is thus possible to deploy the electrode in tissue simultaneously with opening the basket  148 .  
         [0287]      FIGS. 44 and 45  show an operative element  168  comprising a spring biased basket  170 . In the illustrated embodiment, the distal end of the catheter tube  30  carries two electrodes  172 . A single electrode, or more than two electrodes, can be carried in the same fashion on the distal end of the catheter tube  30 .  
         [0288]     The electrodes  172  are formed from a suitable energy transmitting materials, e.g. stainless steel. The electrodes  172  have sufficient distal sharpness and strength to penetrate a desired depth into the smooth muscle of the esophageal or cardia  20  wall.  
         [0289]     The proximal end of each electrode  172  is coupled to the leaf spring  174 . The leaf spring  174  normally biases the electrodes  172  in an outwardly flexed condition facing the proximal end of the catheter tube  30  (as  FIG. 44  shows).  
         [0290]     An electrode cover  176  is slidably mounted on the distal end of the catheter tube  30 . A stylet  178  is coupled to the electrode cover  176 . The stylet  178  is movable axially along the catheter tube  30 , e.g., by a lever on the handle at the proximal end of the catheter tube  30 .  
         [0291]     Pulling on the stylet  178  moves the electrode cover  176  over the electrodes  172  into the position shown in  FIG. 45 . On this position, the cover  176  encloses the electrodes  172 , pulling them inward against the distal end of the catheter tube  30 . Enclosed within the cover  176 , the electrodes  172  are maintained in a low profile condition for passage through the esophagus, e.g., through lower esophageal sphincter  18  and into a position slightly beyond the surface of the cardia  20 .  
         [0292]     Pushing on the stylet  178  moves the electrode cover  176  toward a distal-most position beyond the electrodes  172 , as shown in  FIG. 44 . Progressively unconstrained by the cover  176 , the electrodes  172  spring outward. The outward spring distance of electrodes  172  depends upon the position of the cover  176 . The electrodes  172  reach their maximum spring distance when the cover  176  reaches its distal-most position, as  FIG. 44  shows. The distal ends of the electrodes  172  are oriented proximally, to point, e.g. toward the cardia  20 .  
         [0293]     With the electrodes  172  sprung outward, the physician pulls rearward on the catheter tube  30 . The electrodes  172  penetrate the cardia  20 . The electrodes apply energy, forming subsurface lesions in the cardia  20  in the same fashion earlier described. As  FIG. 44  shows, the proximal region of each electrode  172  is preferably enclosed by an electrical insulating material  70 , to prevent ohmic heating of the mucosal surface of the cardia  20 .  
         [0294]     Upon formation of the lesions, the physician can move the catheter tube  30  forward, to advance the electrodes  172  out of contact with the cardia  20 . By rotating the catheter tube  30 , the physician can reorient the electrodes  172 . The physician can also adjust the position of the cover  176  to increase or decrease the diameter of the outwardly flexed electrodes  172 . Pulling rearward on the catheter tube  30  causes the electrodes to penetrate the cardia  20  in their reoriented and/or resized position. In this way, the physician can form desired ring or rings of lesion patterns, as already described.  
         [0295]     Upon forming the desired lesion pattern, the physician advances the electrodes  172  out of contact with the cardia  20 . The physician moves the cover  176  back over the electrodes  172  (as  FIG. 45  shows). In this condition, the physician can withdraw the catheter tube  30  and operative element  168  from the cardia  20  and esophagus  10 , completing the procedure.  
         [0296]     F. Extruded Electrode Support Structures  
         [0297]     FIGS.  63  to  65  show another embodiment of an operative element  216  suited for deployment in the lower esophageal sphincter  18 , cardia  20 , and other areas of the body. In this embodiment, the operative element  216  comprises an expandable, extruded basket structure  218  (as  FIG. 65  shows).  
         [0298]     The structure  218  is first extruded (see  FIG. 63 ) as a tube  224  with a co-extruded central interior lumen  220 . The tube  224  also includes circumferentially spaced arrays  222  of co-extruded interior wall lumens. Each array  222  is intended to accommodate an electrode  66  and the fluid passages associated with the electrode  66 .  
         [0299]     In each array  222 , one wall lumen accommodates passage of an electrode  66  and related wires. Another lumen in the array  222  is capable of passing fluids used, e.g. to cool the mucosal surface. Another lumen in the array  222  is capable of passing fluids aspirated from the targeted tissue region, if required.  
         [0300]     Once extruded (see  FIG. 64 ), the tube wall is cut to form slits  230  between the lumen arrays  222 . Proximal and distal ends of the tube are left without slits  230 , forming a proximal base  226  and a distal hub  228 . Appropriate ports  232  are cut in the tube wall between the slits  230  to accommodate passage of the electrodes  66  and fluids through the wall lumens. The base  226  is coupled to the distal end of a catheter tube  236 .  
         [0301]     In the illustrated embodiment (see  FIG. 65 ), a pull wire  234  passing through the interior lumen  220  is attached to the distal hub  228 . Pulling on the wire  234  (e.g., by means of a suitable push-pull control on a handle at the proximal end of the catheter tube  236 ) draws the hub  228  toward the base  226  (as  FIG. 65  shows). Alternatively, a push wire joined to the base  226  can advance the base  226  toward the hub  228 .  
         [0302]     In either case, movement of the base  226  and hub  228  toward each other causes the tube  224  to flex outward between the slits  230 , forming, in effect, a spined basket. The extruded basket structure  218  opens, and its maximum diameter expands.  
         [0303]     Conversely, movement of the base  226  and hub  228  apart causes the tube  224  to flex inward between the slits  230 . The extruded basket structure  218  closes and assumes a collapsed condition.  
         [0304]     The central co-extruded lumen  220  is sized to accommodate passage of a guide wire or an endoscope, as will be described in greater detail later.  
         [0305]     G. Cooling and Aspiration  
         [0306]     As previously described with respect to the operative element  36  shown, e.g., in  FIGS. 5, 7 , and  11 , it is desirable to cool the mucosal surface while applying energy to ohmically heat muscle beneath the surface. To accomplish this objective, the operative element  36  includes a means for applying a cooling liquid like sterile water to mucosal tissue at the targeted tissue region and for aspirating or removing the cooling liquid from the targeted tissue region.  
         [0307]     Various constructions are possible.  
         [0308]     (i) Aspiration Through the Spines  
         [0309]     In the embodiment shown in  FIGS. 55 and 56 , the spines  58  extend between distal and proximal ends  60  and  62  of the element  36 , forming a basket  56 . Four spines  58  are shown for purpose of illustration. An expandable balloon structure  72  is located within the basket  56 , as already described. An inflation tube  204  (see  FIG. 56 ) conveys a media to expand the structure  72  during use.  
         [0310]     As  FIGS. 55 and 56  show, each spine  58  comprises three tubes  186 ,  188 , and  190 . Each tube  186 ,  188 , and  190  has an interior lumen.  
         [0311]     The first tube  186  includes an electrode exit port  192  (see  FIG. 56 ). The electrode  66  passes through the exit port  192  for deployment in the manner previously described.  
         [0312]     The second tube  188  includes a cooling port  194 . The cooling liquid passes through the cooling port  194  into contact with mucosal tissue. The cooling port  194  is preferably situated on the outside (i.e., tissue facing) surface of the spine  58 , adjacent the electrode exit port  192  (see  FIG. 56 ).  
         [0313]     The third tube  190  includes an aspiration port  196 . Cooling liquid is aspirated through the port  196 . The port  196  is preferably situated on the inside (i.e. facing away from the tissue) surface of the spine  58 .  
         [0314]     Preferable, at least one of the aspiration ports  196  is located near the distal end  60  of the element  36 , and at least one of the aspiration ports  196  is located near the proximal end  62  of the element  36 . In the illustrated embodiment, two aspiration ports are located near the distal end  60 , on opposite spines  58  (see  FIG. 55 ). Likewise, two aspiration ports are located near the proximal end  62 , on opposite spines  58  (see  FIG. 56 ). This arrangement provides for efficient removal of liquid from the tissue region.  
         [0315]     The electrodes  66  are commonly coupled to the control lever  198  on the handle  28  (see  FIG. 57 ), to which the catheter tube  30  carrying the element  36  is connected. The lumen of the second tube  188  communicates with a port  200  on the handle  28 . In use, the port  200  is coupled to a source of cooling fluid. The lumen of the third tube  190  communicates with a port  202  on the handle  28 . In use, the port  202  is coupled to a vacuum source. The inflation tube  204  communicates with a port  206  on the handle  28 . The port  206  connects to a source of inflation media, e.g., air in a syringe.  
         [0316]     (ii) Interior Aspiration Through an Inner Member  
         [0317]     In the alternative embodiment shown in  FIG. 58A , the spines  58  (eight are shown for purpose of illustration) each comprises at least two tubes  186  and  188 . In  FIG. 58A , the inflation tube  204  extends through the expandable balloon structure  72 , between the distal and proximal ends  60  and  62  of the element  36 . Inflation ports  208  communicate with a lumen within the tube  204  to convey the expansion media into the structure  72 .  
         [0318]     The first tube  186  includes the electrode exit port  192 , through which the electrode  66  passes. The second tube  188  includes the outside facing cooling port  194 , for passing cooling liquid into contact with mucosal tissue.  
         [0319]     At least one aspiration port  196  communicates with a second lumen in the inflation tube  204 . In the illustrated embodiment, two aspiration ports  196  are provided, one near the distal end  60  of the element  36 , and the other near the proximal end  62  of the element  36 .  
         [0320]     The element  36  shown in  FIG. 58A  can be coupled to the handle  28  shown in the  FIG. 57  to establish communication between the tubes  188  and  204  in the manner already described.  
         [0321]     In an alternative embodiment (shown in phantom lines in  FIG. 58A ), a sponge-like, liquid retaining material  320  can be applied about each spine  58  over the electrode exit port  192  and/or of the cooling port  194 . The electrode  66  passes through the spongy material  320 . Cooling liquid passing through the cooling port  194  is absorbed and retained by the spongy material  320 . The spongy material  320  keeps the cooling liquid in contact with mucosal tissue at a localized position surrounding the electrode  66 . By absorbing and retaining the flow of cooling liquid, the spongy material  320  also minimizes the aspiration requirements. The presence of the spongy material  320  to absorb and retain cooling liquid also reduces the flow rate and volume of cooling liquid required to cool mucosal tissue, and could eliminate the need for aspiration altogether.  
         [0322]     In another alternative embodiment, as shown in  FIG. 58B , the spines  58  (eight are shown for purpose of illustration) each comprises a single tube  186 , which includes the electrode exit port  192 , through which includes the electrode exit port  192 , through which the electrode  66  passes. As in  FIG. 58A , the inflation tube  204  in  FIG. 58B  extends through the expandable balloon structure  72 . Inflation ports  208  communicate with a lumen within the tube  204  to convey the expansion media into the structure  72 .  
         [0323]     In this embodiment, the expansion medium comprises the cooling liquid. A pump conveys the cooling liquid into the structure  72 . Filling the structure  72 , the cooling liquid causes expansion. The structure  72  further includes one or more small pinholes PH near each electrode  66 . The cooling liquid “weeps” through the pinholes PH, as the pump continuously conveys cooling liquid into the structure  72 . The cooling liquid contacts and cools tissue in the manner previously described.  
         [0324]     As in  FIG. 58A , at least one aspiration port  196  communicates with a second lumen in the inflation tube  204  to convey the cooling liquid from the treatment site. In  FIG. 58B , two aspiration ports  196  are provided, one near the distal end  60  of the element  36 , and the other near the proximal end  62  of the element  36 .  
         [0325]     (iii) Tip Aspiration/Guide Wire  
         [0326]     In the alternative embodiment shown in  FIG. 59 , the spines  58  (four are shown for purpose of illustration) each comprises at least two tubes  186  and  188 . Like the embodiment shown in  FIG. 58 , the inflation tube  204  in  FIG. 59  extends through the expandable balloon structure  72 , between the distal and proximal ends  60  and  62  of the element  36 . Inflation ports  208  communicate with a lumen within the tube  204  to convey the expansion media into the structure  72 .  
         [0327]     The first tube  186  includes the electrode exit port  192 , through which the electrode  66  passes. The second tube  188  includes the outside facing cooling port  194 , for passing cooling liquid into contact with mucosal tissue.  
         [0328]     In the embodiment shown in  FIG. 59 , the distal end  60  of the element  36  includes an aspiration port  196 , which communicates with a second lumen in the inflation tube  204 .  
         [0329]     The element  36  shown in  FIG. 58  can be coupled to the handle  28  shown in the  FIG. 57  to establish communication between the tubes  188  and  204  in the manner already described.  
         [0330]     In the embodiment shown in  FIG. 59 , the lumen in the inflation tube  204  used for aspiration can be alternatively used to pass a guide wire  210 , as  FIG. 60  shows. The guide wire  210  is introduced through the aspiration port  202  on the handle  28  (as  FIG. 61  shows).  
         [0331]     Use of a guide wire  210  can obviate the need for the introducer  32  previously described and shown in  FIG. 9 , which may in certain individuals cause discomfort. In use, the physician passes the small diameter guide wire  210  through the patient&#39;s mouth and pharynx, and into the esophagus  10  to the targeted site of the lower esophageal sphincter or cardia. The physician can next pass the operative element  36  (see  FIG. 60 ) over the guide wire  210  into position. The physician can also deploy an endoscope next to the guide wire  210  for viewing the targeted site and operative element  36 .  
         [0332]     Use of the guide wire  210  also makes possible quick exchanges of endoscope and operative element  36  over the same guide wire  210 . In this arrangement, the guide wire  210  can serve to guide the endoscope and operative element  36  to the targeted site in quick succession.  
         [0333]     G. Vacuum-Assisted Stabilization of Mucosal Tissue  
         [0334]     As  FIG. 66  shows, mucosal tissue MT normally lays in folds in the area of the lower esophageal sphincter  18  and cardia  20 , presenting a fully or at least partially closed path. In the preceding embodiments, various expandable structures are deployed to dilate the mucosal tissue MT for treatment. When dilated, the mucosal tissue folds expand and become smooth, to present a more uniform surface for submucosal penetration of the electrodes  66 . The dilation mediates against the possibility that an electrode  66 , when deployed, might slide into a mucosal tissue fold and not penetrate the underlying sphincter muscle.  
         [0335]     (i) Rotational Deployment of Electrodes  
         [0336]     FIGS.  67  to  69  show an alternative treatment device  238  suited for deployment in the lower esophageal sphincter  18 , cardia  20 , and other regions of the body to direct electrodes  66  into targeted submucosal tissue regions.  
         [0337]     The device  238  includes a handle  248  (see  FIG. 67 ) that carries a flexible catheter tube  242 . The distal end of the catheter tube  242  carries an operative element  244 .  
         [0338]     The operative element  244  includes a proximal balloon  246  and a distal balloon  248 . The balloons  246  and  248  are coupled to an expansion media by a port  276  on the handle  240 .  
         [0339]     An electrode carrier  250  is located between the balloons  246  and  248 . As  FIGS. 67 and 68  show, the carrier  250  includes a generally cylindrical housing  252  with an exterior wall  268 . The housing  252  includes a series of circumferentially spaced electrode pods  256 . Each pod  256  extends radially outward of the wall  268  of housing  252 .  
         [0340]     As  FIGS. 68 and 69  show, each pod  256  includes an interior electrode guide bore  258 . The guide bore  258  extends in a curved path through the pod  256  and terminates with an electrode port  262  spaced outward from the wall of the housing.  
         [0341]     The housing  252  also includes a series of suction ports  260  (see  FIGS. 68 and 69 ). Each suction port  260  is located flush with the housing wall  268  close to an electrode port  262 . The suction ports  260  are coupled to a source of negative pressure through a port  274  on the handle  240 .  
         [0342]     A driver disk  254  is mounted for rotation within the housing  252 . Electrodes  264  are pivotally coupled to the driver disk  254  on pins  266  arranged in an equally circumferentially spaced pattern.  
         [0343]     The electrodes  264  can be formed from various energy transmitting materials, e.g., 304 stainless steel. The electrodes  264  are coupled to the generator  38 , preferable through the controller  52 .  
         [0344]     The electrodes  264  have sufficient distal sharpness and strength to penetrate a desired depth into the smooth muscle of the esophageal or cardia  20  apply energy from the generator  38 .  
         [0345]     As previously described with respect to other embodiments, an electrical insulating material  278  (see  FIGS. 68 and 69 ) is coated about the proximal end of each electrode  264 . When the distal end of the electrode  264  penetrating the smooth muscle of the esophageal sphincter  18  or cardia  20  transmits radio frequency energy, the material  278  insulates the mucosal surface of the esophagus  10  or cardia  20  from direct exposure to the radio frequency energy to prevent thermal damage to the mucosal surface. As previously described, the mucosal surface can also be actively cooled during application of radio frequency energy, to further protect the mucosal surface from thermal damage.  
         [0346]     Each electrode  264  is biased with a bend, to pass from the pin  266  in an arcuate path through the electrode guide bore  258  in the associated pod  256 . Rotation of the driver disk  254  in one direction (which is clockwise in  FIG. 68 ) moves the electrodes  264  through the bores  258  outward of the carrier  250  (as  FIG. 69  shows). Opposite rotation of the driver disk  254  (which is counterclockwise in  FIG. 68 ) moves the electrodes  264  through the bores  258  inward into the carrier  250  (as  FIGS. 67 and 68  show).  
         [0347]     A drive shaft  270  is coupled to the driver disk  254  to affect clockwise and counterclockwise rotation of the disk  254 . A control knob  272  on the handle  240  (see  FIG. 67 ) is coupled to the drive shaft  254  to extend and retract the electrodes  264 .  
         [0348]     In use, the carrier  250  is located at the desired treatment site, e.g., in the region of the lower esophageal sphincter  18 . The balloons  246  and  248  are expanded to seal the esophagus in the region between the balloons  246  and  248 .  
         [0349]     A vacuum is then applied through the suction ports  260 . The vacuum evacuates air and fluid from the area of the esophageal lumen surrounding the carrier  250 . This will cause the surrounding mucosal tissue to be drawn inward against the wall  268  of the housing  252  (see  FIG. 69 ), to conform and be pulled tightly against the pods  256 .  
         [0350]     Applying a vacuum to draw mucosal tissue inward against the pods  256  causes the tissue to present a surface nearly perpendicular to the electrode ports  262  (see  FIG. 69 ). Operation of the driver disk  254  moves the electrodes  264  through the ports  262 , in a direct path through mucosal tissue and into the underlying sphincter muscle. Due to the direct, essentially perpendicular angle of penetration, the electrode  264  reaches the desired depth in a short distance (e.g., less than 3 mm), minimizing the amount of insulating material  278  required.  
         [0351]     The application of vacuum to draw mucosal tissue against the pods  256  also prevents movement of the esophagus while the electrodes  264  penetrate tissue. The counter force of the vacuum resists tissue movement in the direction of electrode penetration. The vacuum anchors the surrounding tissue and mediates against the “tenting” of tissue during electrode penetration. Without tenting, the electrode  264  penetrates mucosal tissue fully, to obtain a desired depth of penetration.  
         [0352]     (ii) Straight Deployment of Electrodes  
         [0353]      FIGS. 70 and 71  show another alternative treatment device  280  suited for deployment in the lower esophageal sphincter  18 , cardia  20 , and other regions of the body to direct electrodes  66  into targeted submucosal tissue regions.  
         [0354]     The device  280  includes a handle  282  (see  FIG. 70 ) that carries a flexible catheter tube  284 . The distal end of the catheter tube  284  carries an operative element  286 .  
         [0355]     The operative element  286  includes a proximal balloon  288  and a distal balloon  290 . The balloons  288  and  290  are coupled to an expansion media by a port  292  on the handle  284 .  
         [0356]     An electrode carrier  294  is located between the balloons  246  and  248 . The carrier  294  includes a generally cylindrical housing  296  with an exterior wall  298  (see  FIG. 71 ). The housing  296  includes a series of circumferentially and axially spaced recesses  300  in the wall  298  (best shown in  FIG. 70 ).  
         [0357]     As  FIG. 71  shows, an electrode guide bore  302  extends through the wall  298  and terminates with an electrode port  304  in each recess  300 . The axis of each guide bore  302  is generally parallel to the plane of the corresponding recess  300 .  
         [0358]     The housing  296  also includes a series of suction ports  306 , one in each recess  300 . The suction ports  306  are coupled to a source of negative pressure through a port  308  on the handle  282 .  
         [0359]     An electrode mount  310  (see  FIG. 71 ) is mounted for axial movement within the housing  296 . Electrodes  312  are pivotally coupled to the mount  310 .  
         [0360]     The electrodes  312  can be formed from various energy transmitting materials, e.g.,  304  stainless steel. The electrodes  312  are coupled to the generator  38 , preferable through the controller  52 .  
         [0361]     The electrodes  312  have sufficient distal sharpness and strength to penetrate a desired depth into the smooth muscle of the esophageal or cardia  20  to apply energy from the generator  38 . As previously described with respect to other embodiments, an electrical insulating material  314  (see  FIG. 71 ) is coated about the proximal end of each electrode  312 .  
         [0362]     Each electrode  312  is generally straight, to pass from the mount  310  through the electrode guide bore  302 . Axial movement of the mount  310  toward the guide bores  302  extends the electrodes  312  outward into the recesses  300 , as FIG. 71  shows. Opposite axial movement of the mount  310  withdraws the electrodes  312  through the bores  302  inward from recesses  300  (as  FIG. 70  shows).  
         [0363]     A stylet  316  (see  FIG. 71 ) is coupled to the mount  310  to affect axial movement of the mount  310 . A push-pull control knob  318  on the handle  282  is coupled to the stylet  316  to extend and retract the electrodes  264 . Alternatively, a spring loaded mechanism can be used to “fire” the mount  310  to deploy the electrodes  312 .  
         [0364]     In use, the carrier  294  is located at the desired treatment site, e.g., in the region of the lower esophageal sphincter. The balloons  288  and  290  are expanded to seal the esophagus in the region between the balloons  288  and  290 .  
         [0365]     A vacuum is then applied through the suction ports  292 . The vacuum evacuates air and fluid from the area of the esophageal lumen surrounding the carrier  294 . This will cause the surrounding mucosal tissue to be drawn inward into the recesses, to conform and be pulled tightly against the recesses  300 , as  FIG. 71  shows.  
         [0366]     Applying a vacuum to draw mucosal tissue inward into the recesses  300  causes the tissue to present a surface nearly perpendicular to the electrode ports  304 , as  FIG. 71  shows. Operation of the mount  310  moves the electrodes  312  through the ports  304 , in a path through mucosal tissue and into the underlying sphincter muscle that is generally parallel to the axis of the esophageal lumen.  
         [0367]     In the same manner described with regard to the preceding embodiment, the application of vacuum to draw mucosal tissue into the recesses  300  also anchors the carrier  294  in the esophagus while the electrodes  312  penetrate tissue. Ribs and the like can also be provided in the recesses  300  or along the wall  298  of the housing  296  to enhance the tissue anchoring effect. The counter force of the vacuum resists tissue movement in the direction of electrode penetration. The vacuum anchors the surrounding tissue and mediates against the “tenting” of tissue during electrode penetration. The electrodes  312  penetrates mucosal tissue fully, to obtain a desired depth of penetration.  
         [0368]     H. Visualization  
         [0369]     Visualization of the targeted tissue site before, during, and after lesion formation is desirable.  
         [0370]     (i) Endoscopy  
         [0371]     As earlier shown in  FIGS. 9 and 10 , a separately deployed endoscope  84 , carried by a flexible catheter tube  86 , is used to visualize the targeted site. In this embodiment, the operative element  36  is deployed separately, by means of a separate catheter tube  30 .  
         [0372]     In an alternative embodiment (shown in FIGS.  46  to  49 ), a treatment device  26  is deployed over the same catheter tube  86  that carries the endoscope  84 . In effect, this arrangement uses the flexible catheter tube  86  of the endoscope  84  as a guide wire.  
         [0373]     In this embodiment, the treatment device  26  can carry any suitable operative element (which, for this reason, is generically designated OE in FIGS.  46  to  49 ). As  FIGS. 46 and 47  show, the catheter tube  30  passes through and beyond the interior of the operative element OE. The catheter tube  30  further includes a central lumen  180 , which is sized to accommodate passage of the flexible catheter tube  86  carrying the endoscope  84 .  
         [0374]     As shown in  FIG. 48 , once the endoscope  84  is deployed in the manner shown in  FIGS. 9 and 10 , the operative element OE can be passed over the catheter tube  86  to the targeted tissue region. In  FIG. 48 , the targeted region is shown to be the cardia  20 .  
         [0375]     In use, the endoscope  86  extends distally beyond the operative element OE. By retroflexing the endoscope  86 , as  FIGS. 48 and 49  show, the physician can continuously monitor the placement of the operative element OE, the extension of the electrodes  66 , and the other steps of the lesion formation process already described.  
         [0376]     When the operative element OE includes the expandable balloon structure  72  (see  FIGS. 50 and 51 ), the structure  72  and the extent of the catheter tube  30  passing through it, can be formed of a material that is transparent to visible light. In this arrangement, the physician can retract the endoscope  84  into expandable structure  72  (as  FIG. 51  shows). The physician can then monitor the manipulation of the operative element OE and other steps in the lesion formation process from within the balloon structure  72 . Any portion of the catheter tube  30  can be made from a transparent material, so the physician can visualize at other locations along its length.  
         [0377]     As  FIG. 52  shows, the mechanically expanded basket  148  (shown earlier in  FIGS. 41 and 42 ) can likewise be modified for deployment over the catheter tube  86  that carries the flexible endoscope  84 . In this arrangement, the interior lumen  180  extends through the catheter tube  30 , the basket  148 , and beyond the basket hub  152 . The lumen  180  is sized to accommodate passage of the endoscope  84 .  
         [0378]     In another embodiment (see  FIG. 62 ), the endoscope  84  itself can include an interior lumen  212 . A catheter tube  214 , like that previously shown in  FIG. 38 , can be sized to be passed through the interior lumen  212  of the endoscope  84 , to deploy a mono-polar electrode  66  (or a bipolar pair of electrodes) into penetrating contact with a desired tissue region. As  FIG. 62  shows, the electrode  66  can carry a limit collar  121  to resist advancement of the electrode  66  beyond a desired penetration depth.  
         [0379]     In another embodiment, to locate the site of lower esophageal sphincter  18  or cardia  20 , a rigid endoscope can be deployed through the esophagus of an anesthetized patient. Any operative element OE can be deployed at the end of a catheter tube to the site identified by rigid endoscopy, to perform the treatment as described. In this arrangement, the catheter tube on which the operative element is deployed need not be flexible. With an anesthetized patient, the catheter tube that carries the operative element OE can be rigid.  
         [0380]     With rigid endoscopy, the catheter tube can be deployed separately from the endoscope. Alternatively, the catheter tube can include an interior lumen sized to pass over the rigid endoscope.  
         [0381]     (ii) Fluoroscopy  
         [0382]     Fluoroscopy can also be used to visual the deployment of the operative element OE. In this arrangement, the operative element OE is modified to carry one or more radiopaque markers  182  (as  FIG. 24  shows) at one or more identifiable locations, e.g., at the distal hub  60 , or proximal base  62 , or both locations.  
         [0383]     With a patient lying on her left side upon a fluoroscopy table, the physician can track movement of the radiopaque markers  182  to monitor movement and deployment of the operative element OE. In addition, the physician can use endoscopic visualization, as previously described.  
         [0384]     (iii) Ultrasound  
         [0385]     The catheter tube can carry an ultrasound transducer  184  (as  FIG. 21  shows) adjacent the proximal or distal end of the operative element OE. The physician can observe the transesophageal echo as a real time image, as the operative element OE is advanced toward the lower esophageal sphincter  18 . The real time image reflects the thickness of the esophageal wall.  
         [0386]     Loss of the transesophageal echo marks the passage of the ultrasound transducer  184  beyond lower esophageal sphincter  18  into the stomach  12 . The physician pulls back on the catheter tube  30 , until the transesophageal echo is restored, thereby marking the situs of the lower esophageal sphincter  18 .  
         [0387]     With the position of the sphincter localized, the physician can proceed to expand the structure  72 , deploy the electrodes  66 , and perform the steps of procedure as already described. Changes in the transesophageal echo as the procedure progresses allows the physician to visualize lesion formation on a real time basis.  
         [0388]     I. The Graphical User Interface (GUI)  
         [0389]     In the illustrated embodiment (see  FIGS. 72A and 72B ), the radio frequency generator  38 , the controller  52  with I/O device  54 , and the fluid delivery apparatus  44  (for the delivery of cooling liquid) are integrated within a single housing  400 . The I/O device  54  includes input connectors  402 ,  404 , and  406 . The connector  402  accepts an electrical connector  408  coupled to a given treatment device TD. The connector  404  accepts an electrical connector  410  coupled to a patch electrode  412  (for mono-polar operation). The connector  406  accepts a pneumatic connector  414  coupled to a conventional foot pedal  416 . These connectors  402 ,  404 , and  406  couple these external devices to the controller  52 . The I/O device  54  also couples the controller  54  to an array of membrane keypads  422  and other indicator lights on the housing  400  (see  FIG. 73 ), for entering and indicating parameters governing the operation of the controller  52 .  
         [0390]     The I/O device  54  also couples the controller  52  to a display microprocessor  474 , as  FIG. 82  shows. In the illustrated embodiment, the microprocessor  474  comprises, e.g., a dedicated Pentium7-based central processing unit. The controller  52  transmits data to the microprocessor  474 , and the microprocessor  474  acknowledges correct receipt of the data and formats the data for meaningful display to the physician. In the illustrated embodiment, the dedicated display microprocessor  474  exerts no control over the controller  52 .  
         [0391]     In the illustrated embodiment, the controller  52  comprises a 68HC11 processor having an imbedded operating system. Alternatively, the controller  52  can comprise another style of processor, and the operating system can reside as process software on a hard drive coupled to the CPU, which is down loaded to the CPU during system initialization and startup.  
         [0392]     The display microprocessor  474  is coupled to a graphics display monitor  420 . The controller  52  implements through the display microprocessor  474  a graphical user interface, or GUI  424 , which is displayed on the display monitor  420 . The GUI  424  can be realized, e.g., as a “C” language program implemented by the microprocessor  474  using the MS WINDOWS™ or NT application and the standard WINDOWS 32 API controls, e.g., as provided by the WINDOWS™ Development Kit, along with conventional graphics software disclosed in public literature.  
         [0393]     The display microprocessor  474  is also itself coupled to a data storage module or floppy disk drive  426 . The display microprocessor  474  can also be coupled to a keyboard, printer, and include one or more parallel port links and one or more conventional serial RS-232C port links or EthernetJ communication links.  
         [0394]     The fluid delivery apparatus  44  comprises an integrated, self priming peristaltic pump rotor  428  with a tube loading mechanism, which are carried on a side panel of the housing  400 . Other types of non-invasive pumping mechanisms can be used, e.g., a syringe pump, a shuttle pump, or a diaphragm pump.  
         [0395]     In the illustrated embodiment, the fluid delivery apparatus  44  is coupled to the I/O device  54  via a pump interface  476 . The pump interface  476  includes imbedded control algorithms that monitor operation of the pump rotor  428 .  
         [0396]     For example, the pump interface  476  can monitor the delivery of electrical current to the pump rotor  428 , to assure that the rotor  428  is operating to achieve a desired flow rate or range of flow rates during use, or, upon shut down, the rotor  428  has stopped rotation. An optical encoder or magnetic Halls effect monitor can be used for the same purpose.  
         [0397]     Alternatively, a flow rate transducer or pressure transducer, or both, coupled to the pump interface  476 , can be placed in line along the pump tubing, or in the treatment device TD itself, to monitor flow rate.  
         [0398]     Flow rate information acquired from any one of these monitoring devices can also be applied in a closed loop control algorithm executed by the controller  52 , to control operation of the pump rotor  428 . The algorithm can apply proportional, integral, or derivative analysis, or a combination thereof, to control operation of the pump rotor  428 .  
         [0399]     In the illustrated embodiment, it is anticipated that the physician will rely upon the vacuum source typically present in the physician&#39;s suite as the aspiration apparatus  46 . However, it should be appreciated that the device  400  can readily integrate the aspiration apparatus  46  by selectively reversing the flow direction of the pump rotor  428  (thereby creating a negative pressure) or by including an additional dedicated pump rotor or equivalent pumping mechanism to perform the aspiration function.  
         [0400]     In the illustrated embodiment, the integrated generator  38  has four independent radio frequency channels. Each channel is capable of supplying up to  15  watts of radio frequency energy with a sinusoidal waveform at 460 kHz. As before explained, the four channels of the generator  38  can operate four electrodes in either a monopolar or bipolar mode. As also explained earlier, the four channels can also be configured to operate eight electrodes either in a monopolar mode or a bipolar mode.  
         [0401]     The integrated controller  52  receives two temperature measurements through the I/O device  54  for each channel, one from the tip of each electrode on the treatment device TD, and one from tissue surrounding the electrode. The controller  52  can regulate power to the electrodes in a close-loop based upon the sensed tip temperature, or the sensed tissue temperature, or both, to achieve and maintain a targeted tip tissue temperature at each electrode. The controller  52  can also regulate power to the pump rotor  428  in a closed-loop based upon the sensed tip temperature, or the sensed tissue temperature, or both, to achieve and maintain a targeted tissue temperature at each electrode. Alternatively, or in combination, the physician can manually adjust the power level or pump speed based upon a visual display of the sensed tip and tissue temperatures.  
         [0402]     As  FIG. 73  best shows, the membrane keypads  422  and other indicators on the front panel of the device  400  show the various operational parameters and operating states and allow adjustments to be made. In the illustrated embodiment, as shown in  FIG. 73 , the keypads  422  and indicators include:  
         [0403]     1. Standby/Ready Button  430 , which allows switching from one mode of operation to another, as will be described later.  
         [0404]     2. Standby/Ready Indicator  432 , which displays a green light after the device  400  passes a self test upon start up.  
         [0405]     3. RF On Indicator  434 , which displays a blue light when radio frequency energy is being delivered.  
         [0406]     4. Fault Indicator  436 , which displays a red light when an internal error has been detected. No radio frequency energy can be delivered when the Fault Indicator  436  is illuminated.  
         [0407]     5. Target Duration Keys  438 , which allow increases and decreases in the target power duration at the start or during the course of a procedure.  
         [0408]     6. Target Temperature Keys  440 , which allow increases and decreases in the target temperature at the start or during the course of a procedure.  
         [0409]     7. Maximum Power Keys  442 , which allow increases and decreases in the maximum power setting at the start or during the course of a procedure.  
         [0410]     8. Channel Selection Keys  444 , which allow selection of any or all power channels.  
         [0411]     9. Coagulation Level Keys  446 , which manually increases and decreases the magnitude of the indicated depth of insertion of the electrodes within the esophagus. This depth is determined, e.g., by visually gauging the measured markings along the length of the catheter tube of the treatment device TD, as previously described. Alternatively, the coagulation level can be automatically detected by, e.g., placing optical, mechanical, or magnetic sensors on the mouth piece  82 , which detect and differentiate among the measured markings along the catheter tube of the treatment device TD to read the magnitude of the depth of insertion.  
         [0412]     10. Flow Rate and Priming Keys  448 , which allow for selection of three internally calibrated flow rates, low (e.g., 15 ml/min), medium (e.g., 30 ml/min), and high (e.g., 45 ml/min). Pressing and holding the “Up”key activates the pump at a high flow rate for priming, overruling the other flow rates until the “Up” key is released.  
         [0413]     In the illustrated embodiment, the graphics display monitor  420  comprises an active matrix LCD display screen located between the membrane keypads  422  and other indicators on the front panel. The GUI  424  is implemented by showing on the monitor  420  basic screen displays. In the illustrated embodiment, these displays signify four different operating modes: Start-Up, Standby, Ready, RF-On, and Pause.  
         [0414]     (i) Start Up  
         [0415]     Upon boot-up of the CPU, the operating system implements the GUI  424 . The GUI  424  displays an appropriate start-up logo and title image (not shown), while the controller  52  performs a self-test. A moving horizontal bar or the like can be displayed with the title image to indicate the time remaining to complete the start-up operation.  
         [0416]     (ii) Standby  
         [0417]     Upon completion of the start-up operation, the Standby screen is displayed, as shown in  FIG. 74 . No radio frequency energy can be delivered while the Standby screen is displayed.  
         [0418]     There are various icons common to the Standby, Ready, RF-On, and Pause screens.  
         [0419]     The Screen Icon  450  is an icon in the left hand corner of the monitor  420 , which indicates the operating condition of the treatment device TD and its position inside or outside the esophagus. In  FIG. 74 , the treatment device TD is shown to be disconnected and outside the esophagus. Pressing the “Up” priming key  448 , to cause cooling liquid to flow through the treatment device TD, causes an animated priming stream PS to be displayed along the treatment device TD in the icon, as  FIG. 73  shows. The animated priming stream PS is displayed in the Screen Icon  450  whenever the pump rotor  428  is operating to indicate the supply of cooling fluid through the treatment TD.  
         [0420]     There are also parameter icons designating target duration  452 , target temperature  454 , maximum power  456 , channel selection  458 , coagulation level  460 , and flow rate/priming  462 . These icons are aligned with, respectively, the corresponding Target Duration Keys  438 , Target Temperature Keys  440 , Maximum Power Keys  442 , Channel Selection Keys  444 , Coagulation Level Keys  446 , and Flow Rate and Priming Keys  448 . The icons  452  to  462  indicate current selected parameter values. The flow rate/priming icon  462  shows the selected pump speed by highlighting a single droplet image (low speed), a double droplet image (medium speed), and a triple droplet image (high speed).  
         [0421]     There is also a floppy disk icon  464  that is normally dimmed, along with the coagulation level icon  460 , until a floppy disk is inserted in the drive  426 . When a floppy disk is inserted in the drive  426 , the icons  460  and  464  are illuminated (see  FIG. 73 ), and data is saved automatically after each application of radio frequency energy (as will be described later).  
         [0422]     There is also an Electrode Icon  466 . The Electrode Icon  466  comprises an idealized graphical image, which spatially models the particular multiple electrode geometry of the treatment device TD selected to be deployed in the esophagus. As  FIG. 74  shows, four electrodes are shown in the graphic image of the Icon  466 , which are also spaced apart by 90 degrees. This graphic image is intended to indicate that the selected treatment device TD has the geometry of the four-electrode configuration shown, e.g., in  FIG. 5 .  
         [0423]     For each electrode, the Icon  466  presents in a spatial display the magnitude of tip temperature as actually sensed (in outside box B 1 ) and the magnitude of tissue temperatures as actually sensed (in inside box B 2 ). Until a treatment device TD is connected, two dashes appear in the boxes B 1  and B 2 . The existence of a faulty electrode in the treatment device will also lead to the same display.  
         [0424]     The controller  52  prohibits advancement to the Ready screen until numeric values register in the boxes B 1  and B 2 , as  FIG. 75  shows. The display of numeric values indicate a functional treatment device TD.  
         [0425]     No boxes B 1  or B 2  will appear in the Icon  466  for a given electrode if the corresponding electrode/channel has been disabled using the Channel Selection Keys  444 , as  FIG. 76  shows. In the illustrated embodiment, the physician is able to manually select or deselect individual electrodes using the Selection Keys  444  in the Standby or Ready Modes, but not in the RF-On Mode. However, the controller  52  can be configured to allow electrode selection while in the RF-On Mode, if desired.  
         [0426]     While in the Standby Mode, the physician connects the treatment device TD to the device  400 . The physician couples the source of cooling liquid to the appropriate port on the handle of the device TD (as previously described) and loads the tubing leading from the source of cooling liquid (e.g., a bag containing sterile water) in the pump rotor  428 . The physician also couples the aspiration source to the appropriate port on the handle of the treatment device TD (as also already described). The physician also couples the patch electrode  412  and foot pedal  416 . The physician can now deploy the treatment device TD to the targeted tissue region in the esophagus, in the manners previously described. The physician extends the electrodes through mucosal tissue and into underlying smooth muscle.  
         [0427]     Once the treatment device TD is located at the desired location and the electrodes are deployed, the physician presses the Standby/Ready Button  430  to advance the device  400  from Standby to Ready Mode.  
         [0428]     (iii) Ready  
         [0429]     In the Ready Mode, the controller  52  commands the generator  38  to apply bursts of low level radio frequency energy through each electrode selected for operation. Based upon the transmission of these low level bursts of energy by each electrode, the controller  52  derives a local impedance value for each electrode. The impedance value indicates whether or nor the given electrode is in desired contact with submucosal, smooth muscle tissue. The use of impedance measurements for this purpose has been previously explained.  
         [0430]     As  FIG. 77  shows, the Ready screen updates the Screen Icon  450  to indicate that the treatment device TD is connected and deployed in the patient&#39;s esophagus. The Ready screen also intermittently blinks the RF On Indicator  434  to indicate that bursts of radio frequency energy are being applied by the electrodes. The Ready screen also updates the Electrode Icon  466  to spatially display in the inside and outside boxes B 1  and B 2  the actual sensed temperature conditions. The Ready screen also adds a further outside box B 3  to spatially display the derived impedance value for each electrode.  
         [0431]     On the Ready screen, instantaneous, sensed temperature readings from the tip electrode and tissue surface, as well as impedance values, are continuously displayed in spatial relation to the electrodes the boxes B 1 , B 2 , and B 3  in the Electrode Icon  466 . An “acceptable” color indicator (e.g., green) is also displayed in the background of box B 1  as long as the tip temperature reading is within the desired pre-established temperature range (e.g., 15 to 120 C). However, if the tip temperature reading is outside the desired range, the color indicator changes to an “undesirable” color indicator (e.g., to white), and two dashes appear in box B 1  instead of numeric values.  
         [0432]     The controller  52  prevents the application of radio frequency energy if any temperature reading is outside a selected range (e.g., 15 to 120° 0  C.).  
         [0433]     The physician selects the “Up” key of the Flow Rate and Priming Keys  448  to operate the pump rotor  428  to prime the treatment device TD with cooling fluid. An animated droplet stream PS is displayed along the treatment device TD in the Icon  450 , in the manner shown in  FIG. 75 , to indicate the delivery of cooling liquid by the pump rotor  428 .  
         [0434]     By touching the Target Duration Keys  438 , the Target Temperature Keys  440 , the Maximum Power Keys  442 , the Channel Selection Keys  444 , the Coagulation Level Keys  446 , and the Flow Rate and Priming Keys  448 , the physician can affect changes to the parameter values for the intended procedure. The controller  52  automatically adjusts to take these values into account in its control algorithms. The corresponding target duration icon  452 , target temperature icon  454 , maximum power icon  456 , channel selection icon  458 , coagulation level icon  460 , and flow rate/priming icon  462  change accordingly to indicate the current selected parameter values.  
         [0435]     When the physician is ready to apply energy to the targeted tissue region, the physician presses the foot pedal  416 . In response, the device  400  advances from Ready to RF-On Mode, provided that all sensed temperatures are within the selected range.  
         [0436]     (iv) RF-On  
         [0437]     When the foot pedal  416  is pressed, the controller  52  activates the pump rotor  428 . Cooling liquid is conveyed through the treatment device TD into contact with mucosal tissue at the targeted site. At the same time, cooling liquid is aspirated from the treatment device TD in an open loop. During a predetermined, preliminary time period (e.g. 2 to 5 seconds) while the flow of cooling liquid is established at the site, the controller  52  prevents the application of radio frequency energy.  
         [0438]     After the preliminary time period, the controller  52  applies radio frequency energy through the electrodes. The RF-On screen, shown in  FIG. 79 , is displayed.  
         [0439]     The RF-On screen displays the Screen Icon  450 , indicate that the treatment device TD is connected and deployed in the patient&#39;s esophagus. The flow drop animation PS appears, indicating that cooling is taking place. A flashing radio wave animation RW also appears, indicating that radio frequency energy is being applied. The RF On Indicator  434  is also continuously illuminated to indicate that radio frequency energy is being applied by the electrodes.  
         [0440]     The RF-On screen also updates the Electrode Icon  466  to display in the box B 1  the actual sensed tip temperature conditions. The RF-On screen also displays the derived impedance value for each electrode in the boxes B 3 .  
         [0441]     Unlike the Ready or Standby screens, the surface temperature is no longer displayed in a numerical format in a box B 2 . Instead, a circle C 1  is displayed, which is color coded to indicate whether the surface temperature is less than the prescribed maximum (e.g., 45° C.). If the surface temperature is below the prescribed maximum, the circle is colored an “acceptable” color, e.g., green. If the surface temperature exceeds the prescribed maximum, the color of the circle changes to a “not acceptable” color, e.g., to red.  
         [0442]     Likewise; in addition to displaying numeric values, the boxes B 1  and B 3  are also color coded to indicate compliance with prescribed limits. If the tip temperature is below the prescribed maximum (e.g., 100° C.), the box B 1  is colored, e.g., green. If the tip temperature exceeds the prescribed maximum, the box border thickens and the color of the box B 1  changes, e.g., to red. If the impedance is within prescribed bounds (e.g., between 25 ohms and 1000 ohms), the box B 3  is colored, e.g., grey. If the impedance is outside the prescribed bounds, the box border thickens and the color of the box B 3  changes, e.g., to red.  
         [0443]     If desired, the Electrode Icon  466  can also display in a box or circle the power being applied to each electrode in spatial relation to the idealized image.  
         [0444]     The RF-On screen displays the target duration icon  452 , target temperature icon  454 , maximum power icon  456 , channel selection icon  458 , coagulation level icon  460 , and flow rate/priming icon  462 , indicating the current selected parameter values. The physician can alter the target duration or target temperature or maximum power and pump flow rate through the corresponding selection keys  438 ,  440 ,  442 , and  448  on the fly, and the controller  52  and GUI instantaneously adjust to the new parameter settings. As before mentioned, in the illustrated embodiment, the controller  52  does not permit change of the channel/electrode while radio frequency energy is being applied, and, for this reason, the channel selection icon  458  is dimmed.  
         [0445]     Unlike the Standby and Ready screens, the RF-On screen also displays a real time line graph  468  to show changes to the temperature profile (Y-axis) over time (X-axis). The RF-On screen also shows a running clock icon  470 , which changes appearance to count toward the target duration. In the illustrated embodiment, a digital clock display CD is also shown, indicating elapsed time.  
         [0446]     The line graph  468  displays four trending lines to show the minimum and maximum surface and tip temperature readings from all active electrodes. In the illustrated embodiment, the time axis (X-axis) is scaled to one of five pre-set maximum durations, depending upon the set target duration. For example, if the target duration is 0 to 3 minutes, the maximum time scale is 3:30 minutes. If the target duration is 3 to 6 minutes, the maximum time scale is 6:30 seconds, and so on.  
         [0447]     The line graph  468  displays two background horizontal bars HB 1  and HB 2  of different colors. The upper bar HB 1  is colored, e.g., green, and is centered to the target coagulation temperature with a spread of plus and minus 10° C. The lower bar HB 2  is colored, e.g., red, and is fixed at a prescribed maximum (e.g., 40° C.) to alert potential surface overheating.  
         [0448]     The line graph  468  also displays a triangle marker TM of a selected color (e.g., red)(see  FIG. 80 ) with a number corresponding to the channel/electrode that is automatically turned off by the controller  52  due to operation outside the selected parameters. As before described, the circle C 1  and boxes B 1  and B 3  for this electrode/channel are also modified in the electrode icon  466  when this situation occurs.  
         [0449]     The Electrode Icon  466  can graphically display other types of status or configuration information pertinent to the treatment device TD. For example, the Electrode Icon  466  can display a flashing animation in spatial relation to the idealized electrodes to constantly remind the physician that the electrode is extended into tissue. The flashing animation ceases to be shown when the electrode is retracted. The flashing animation reminds the physician to retract the electrodes before removing the treatment device TD. As another example, the Electrode Icon  466  can display another flashing animation when the expandable structure of the treatment device TD is expanded. The flashing animation reminds the physician to collapse the electrodes before removing the treatment device TD.  
         [0450]     (v) Pause  
         [0451]     The controller  52  terminates the conveyance of radio frequency ablation energy to the electrodes and the RF-On screen changes into the Pause screen (see  FIG. 81 ), due to any of the following conditions (i) target duration is reached, (ii) all channels/electrodes have an erroneous coagulation condition (electrode or surface temperature or impedance out of range), or (iii) manual termination of radio frequency energy application by pressing the foot pedal  416  or the Standby/Ready Button  430 .  
         [0452]     Upon termination of radio frequency ablation energy, the running clock icon  470  stops to indicate total elapsed time. The controller  52  commands the continued supply of cooling liquid through the treatment device TD into contact with mucosal tissue at the targeted site. At the same time, cooling liquid is aspirated from the treatment device TD in an open loop. This flow of cooling liquid continues for a predetermined time period (e.g. 2 to 5 seconds) after the supply of radio frequency ablation energy is terminated, after which the controller  52  stops the pump rotor  428 .  
         [0453]     During Pause, the controller  52  continues to supply intermittent bursts of low power radio frequency energy to acquire impedance information.  
         [0454]     The Pause screen is in most respects similar to the RF-On screen. The Pause screen displays the Screen Icon  450 , to indicate that the treatment device TD is connected and deployed in the patient&#39;s esophagus. The flashing radio wave animation is not present, indicating that radio frequency energy is no longer being applied. The RF On Indicator  434  is, however, intermittently illuminated to indicate that bursts of radio frequency energy are being applied by the electrodes to acquire impedance information.  
         [0455]     The RF-On screen also updates the Electrode Icon  466  to display in the boxes B 1  and B 3  the actual sensed tip temperature and impedance conditions. However, no background color changes are registered on the Pause screen, regardless of whether the sensed conditions are without or outside the prescribed ranges.  
         [0456]     The Pause screen continues to display the target duration icon  452 , target temperature icon  454 , maximum power icon  456 , channel selection icon  458 , coagulation level icon  460 , and flow rate/priming icon  462 , indicating the current selected parameter values.  
         [0457]     The real time temperature line graph  468  continues to display the four trending lines, until the target duration is reached and five additional seconds elapse, to show the drop off of electrode temperature.  
         [0458]     If further treatment is desired, pressing the Standby/Ready button  430  returns the device  400  from the Pause back to the Ready mode.  
         [0459]     (vi) Procedure Log  
         [0460]     As previously described, the floppy disk icon  464  and coagulation level icon  460  are normally dimmed on the various screens, until a floppy disk is inserted in the drive  426 . When a floppy disk is inserted in the drive  426 , the icons  460  and  464  are illuminated, and data is saved automatically after each application of radio frequency energy.  
         [0461]     When the floppy disk is inserted, the controller  52  downloads data to the disk each time it leaves the RF-On screen, either by default or manual termination of the procedure. The downloaded data creates a procedure log. The log documents, by date of treatment and number of treatments, the coagulation level, the coagulation duration, energy delivered by each electrode, and the coolant flow rate. The procedure log also records at pre-established intervals (e.g., every 5 seconds) the temperatures of the electrode tips and surrounding tissue, impedance, and power delivered by each electrode. The procedure log preferably records these values in a spreadsheet format.  
         [0462]     The housing  400  can carry an integrated printer, or can be coupled through the I/O device  54  to an external printer. The printer prints a procedure log in real time, as the procedure takes place.  
         [0463]     Various features of the invention are set forth in the following claims.