Abstract:
A method for treating the lung during an acute episode of reversible chronic obstructive pulmonary disease such as an asthma attack. The method comprises transferring energy to an airway wall of an airway such that a diameter of the airway is increased. The energy may be transferred to the airway wall prior to, during or after an asthma attack. The energy may be transferred in an amount sufficient to temporarily or permanently increase the diameter of the airway. The method may be performed while the airway is open, closed or partially closed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. application Ser. No. 13/590,129, filed Aug. 20, 2012, which is a continuation of U.S. application Ser. No. 12/328,582, filed Dec. 4, 2008, now U.S. Pat. No. 8,267,094, which is a continuation of U.S. application Ser. No. 11/117,905, filed Apr. 29, 2005, now U.S. Pat. No. 7,740,017, which is: 
         [0002]    (a) a continuation of U.S. application Ser. No. 09/999,851, filed Oct. 25, 2001, now U.S. Pat. No. 7,027,869, which is a continuation-in-part application of U.S. application Ser. No. 09/296,040, filed Apr. 21, 1999, now U.S. Pat. No. 6,411,852, which is a continuation-in-part application of U.S. application Ser. No. 09/095,323, filed Jun. 10, 1998, now abandoned, each of which are herein incorporated by reference in their entirety, 
         [0003]    (b) a continuation-in-part application of U.S. application Ser. No. 09/436,455, filed Nov. 8, 1999, now U.S. Pat. No. 7,425,212, which is incorporated by reference herein in its entirety, and 
         [0004]    (c) a continuation-in-part application of U.S. application Ser. No. 10/232,909, filed Aug. 30, 2002, now U.S. Pat. No. 7,556,624, which is a continuation of U.S. application Ser. No. 09/349,715, filed Jul. 8, 1999, now U.S. Pat. No. 6,488,673, which is a continuation-in-part application of U.S. application Ser. No. 09/260,401, filed Mar. 1, 1999, now U.S. Pat. No. 6,283,988, which is a continuation-in-part application of U.S. application Ser. No. 09/003,750, filed Jan. 7, 1998, now U.S. Pat. No. 5,972,026, which is a continuation-in-part application of U.S. application Ser. No. 08/833,550, filed Apr. 7, 1997, now U.S. Pat. No. 6,273,907, each of which are herein incorporated by reference in their entirety. 
         [0005]    U.S. application Ser. No. 09/999,851, now U.S. Pat. No. 7,027,869, is also a continuation-in-part application of U.S. application Ser. No. 09/535,856, filed Mar. 27, 2000, now U.S. Pat. No. 6,634,363, which is also incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0006]    1. Field of the Invention 
         [0007]    The invention relates to a method for treating lung disease, and more particularly, the invention relates to a method of increasing gas exchanging of a lung by stiffening an airway of the lung. 
         [0008]    2. Brief Description of the Related Art 
         [0009]    The lungs deliver oxygen to the body and remove carbon dioxide. Healthy lung tissue includes a multitude of air passageways which lead to respiratory bronchiole within the lung. These airways eventually lead to small sacs called alveoli, where the oxygen and carbon dioxide are exchanged through the ultra-thin walls of the alveoli. This occurs deep within the lungs, in an area which is accessed by a network of airways, consisting of a series of branching tubes which become narrower, shorter, and more numerous as they penetrate deeper into the lungs. As shown in  FIG. 1 , tiny air sacks called alveoli  1  surround both alveolar ducts  2  and respiratory bronchiole  3  throughout the lung. The alveoli  1  are small, polyhedral recesses composed of a fibrillated connective tissue and surrounded by a few involuntary muscular and elastic fibers. These alveoli  1  inflate and deflate with air when we breath. The alveoli are generally grouped together in a tightly packed configuration called an alveolar sac. The thin walls of the alveoli  1  perform gas exchange as we inhale and exhale. 
         [0010]    During inhalation, as the diaphragm contracts and the ribs are raised, a vacuum is created in the chest, and air is drawn into the lungs. As the diaphragm relaxes, normal lungs act like a stretched balloon and rebound to the normal relaxed state, forcing air out of the lungs. The elasticity of the lungs is maintained by the supportive structure of the alveoli. This network of connective tissue provides strength to the airway walls, as well as elasticity to the lungs, both of which contribute to the lung&#39;s ability to function effectively. 
         [0011]    Patients with pulmonary disease, such as chronic bronchitis, and emphysema have reduced lung capacity and efficiency, typically due to the breakdown of lung tissue. 
         [0012]    In cases of severe chronic pulmonary disease, such as emphysema, lung tissue is destroyed, reducing the strength of the airways. This reduction in strength of the airway walls allows the walls to become “floppy” thereby losing their-ability to remain open during exhalation. In the lungs of an emphysema patient, illustrated in  FIG. 2 , the walls between adjacent alveoli within the alveolar sac deteriorate. This wall deterioration is accelerated by the chemicals in smoke which affect the production of mucus in the lungs. Although the break down of the walls of the alveoli in the lungs occurs over time even in a healthy patient, this deterioration is greatly accelerated in a smoker causing the smoker&#39;s lungs to have multiple large spaces  4  with few connecting walls in the place of the much smaller and more dense alveoli spaces  1  in healthy lung tissue. 
         [0013]    A cross section of a diseased emphysematous lung will look like Swiss cheese due to the deterioration of the alveoli walls which leaves large spaces in the tissue. In contrast, healthy lung tissue when seen in cross section has no noticeable holes because of the small size of the alveoli. When many of the walls of the alveoli  1  have deteriorated as shown in  FIG. 2 , the lung has larger open spaces  4  and a larger overall volume, but has less wall tissue to achieve gas exchange. 
         [0014]    In this diseased state, the patient suffers from the inability to get the air out of their lungs due to the collapse of the airways during exhalation. Heavily diseased areas of the lung become overinflated. Within the confines of the chest cavity, this overinflation restricts the in-flow of fresh air and the proper function of healthier tissue, resulting in significant breathlessness. Thus, the emphysema patient must take in a greater volume of air to achieve the same amount of gas exchange. When severe emphysema patients take in as much air as their chest cavity can accommodate, they still have insufficient gas exchange because their chest is full of non-functional air filling large cavities in the lungs. Emphysema patients will often look barrel-chested and their shoulders will elevate as they strain to make room for their overinflated lungs to work. 
         [0015]    A wide variety of drugs are available for treating the symptoms of pulmonary disease, but none are curative. Chronic bronchitis and emphysema are typically treated with antibiotics and bronchodilators. Unfortunately, a large number of patients are not responsive to these medications or become non-responsive after prolonged periods of treatment. 
         [0016]    In severe emphysema cases, lung volume reduction surgery (LVRS) is performed to improve lung efficiency of the patient and allow the patient to regain mobility. In lung volume reduction surgery, a more diseased portion of an emphysematous lung having a large amount of alveolar wall deterioration is surgically removed. LVRS is performed by opening the chest cavity, retracting the ribs, stapling off, and removing the more diseased portion of the lung. This allows the remaining healthier lung tissue to inflate more fully and take greater advantage of the body&#39;s ability to inhale and exhale. Because there is more air and more gas exchange in the healthier portion of the lung, lung efficiency is improved. 
         [0017]    Lung volume reduction surgery is an extremely invasive procedure requiring the surgical opening of the chest cavity and removal of lung tissue. This surgery has substantial risks of serious post-operative complications, such as pneumothorax, and requires an extended convalescence. 
         [0018]    Accordingly, it is desirable to improve air exchange for patients having chronic obstructive pulmonary diseases, such as chronic bronchitis and emphysema. It is especially desirable to achieve improved air exchange of emphysema patients without invasive open chest surgery and the associated complications. 
       SUMMARY OF THE INVENTION 
       [0019]    The present invention pertains to methods of increasing gas exchange of the lungs of a patient. According to the present invention, gas exchange is increased by stiffening, strengthening, or destroying airway smooth muscle tone of at least one airway of a lung. 
         [0020]    In accordance with one aspect of the present invention, a method includes: inserting an apparatus into an airway of a lung, and damaging lung cells with the apparatus to cause fibrosis to stiffen the airway so as to increase gas exchange performed by the lung. 
         [0021]    In accordance with another aspect of the present invention, a method includes: inserting an apparatus into an airway of a lung; and damaging tissue in the lung with the apparatus to increase gas exchange performed by the lung. 
         [0022]    In accordance with a further aspect of the present invention, a method of increasing gas exchange performed by the lung, includes: inserting an apparatus into an airway of a lung; and causing trauma to tissue with the apparatus to cause fibrosis to stiffen the airway. Causing trauma to the tissue with the apparatus includes at least one of: heating the tissue; cooling the tissue; delivering a liquid that cause trauma to the tissue; delivering a gas that cause trauma to the tissue; puncturing the tissue; tearing the tissue; cutting the tissue; applying ultrasound to the tissue; and applying ionizing radiation to the tissue. 
         [0023]    Another aspect of the present invention pertains to a method including: inserting an apparatus into an airway of a lung; and destroying airway smooth muscle tone with the apparatus to increase gas exchange performed by the lung. 
         [0024]    A further aspect of the present invention pertains to a method of increasing gas exchange performed by a lung. The method includes inserting an apparatus into an airway of a lung, and damaging airway tissue with the apparatus to thicken a wall of the airway. 
         [0025]    The present invention provides advantages of a minimally invasive procedure for surgically treating the effects of pulmonary disease, such as chronic pulmonary disease, without the complications associated with conventional surgery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The invention will now be described in greater detail with reference to the preferred embodiments illustrated in the accompanying drawings, in which like elements bear like reference numerals, and wherein: 
           [0027]      FIG. 1  is a cross-sectional view of an alveolar sack of a healthy lung; 
           [0028]      FIG. 2  is a cross-sectional view of an alveolar sack of a diseased lung; 
           [0029]      FIG. 3  is an illustration of a lung having a diseased lower portion prior to treatment according to the present invention; 
           [0030]      FIG. 4  is a perspective view of the airway of a lung, wherein the smooth muscle tissue, alveolar sacks, and alveoli are illustrated; 
           [0031]      FIG. 5  is a cross-sectional view of the airway of  FIG. 4  taken along the line  5 - 5  of  FIG. 4 ; 
           [0032]      FIG. 6  is a schematic side view of lungs being treated with the treatment apparatus in accordance with one embodiment of the present invention; 
           [0033]      FIG. 6A  is a schematic cross-sectional view of the airway of  FIG. 6  before treatment taken along the line  6 A- 6 A of  FIG. 6 ; 
           [0034]      FIG. 6B  is a schematic cross-sectional view of the airway of  FIG. 6A  after being treated in accordance with one method of the present invention; 
           [0035]      FIG. 7  is a schematic side view of lungs being treated with a treatment apparatus in accordance with one embodiment of the present invention; 
           [0036]      FIGS. 8 ,  9 ,  10 A,  10 B,  11 A and  11 B are perspective views of heat treatment apparatus for use with the methods of the present invention; 
           [0037]      FIGS. 12A and 12B  are cross-sectional views of heat treatment apparatus for use with the methods of the present invention; 
           [0038]      FIG. 13A  is a schematic view of an embodiment of the treatment apparatus for use with the methods of the present invention; 
           [0039]      FIG. 13B  is an enlarged view of the circled portion of  FIG. 13A ; 
           [0040]      FIG. 13C  illustrates another embodiment of a treatment apparatus for use with the methods of the present invention; 
           [0041]      FIGS. 14A ,  14 B,  15 A,  15 B,  16 A,  16 B,  17 A, and  17 B illustrate additional embodiments of the heat treatment apparatus which employ RF energy for use with the methods of the present invention; 
           [0042]      FIG. 18  illustrates an embodiment of the heat treatment apparatus which employs circulating heated fluid for use with the methods of the present invention; 
           [0043]      FIG. 19  illustrates an embodiment of the heat treatment apparatus that has both resistive heating and inductive heating for use with the methods of the present invention; 
           [0044]      FIGS. 20A and 20B  illustrate an embodiment of a heat treatment apparatus that employs electrodes positioned on the outer surface of a balloon for use with the methods of the present invention; 
           [0045]      FIGS. 21 ,  22 , and  23  show embodiments of the heat treatment apparatus that employ diametrically adjustable electrodes for use with the methods of the present invention; 
           [0046]      FIG. 24  illustrates a heat treatment apparatus with multiple electrodes for use with the methods of the present invention; 
           [0047]      FIG. 25  illustrates a heat treatment apparatus with multiple balloons for use with the methods of the present invention; 
           [0048]      FIG. 26  is a schematic side view of one embodiment of a heat treatment apparatus that employs two collapsible and retractable electrodes for use with the methods of the present invention; 
           [0049]      FIG. 27  is an enlarged partial cross-sectional view of a distal end of another embodiment of a heat treatment apparatus having one collapsible electrode for use with the methods of the present invention; 
           [0050]      FIG. 28  is a side cross-sectional view of an alternative embodiment of a heat treatment apparatus having two wire shaped electrodes for use with the methods of the present invention; 
           [0051]      FIG. 29  is a side cross-sectional view of the device of  FIG. 28  in an enlarged state within a bronchial tube; 
           [0052]      FIG. 30  is a side cross-sectional view of an alternative embodiment of a heat treatment apparatus with four electrodes in an enlarged state within a bronchial tube for use with the methods of the present invention; 
           [0053]      FIG. 30A  is an end view of the device of  FIG. 30 ; 
           [0054]      FIG. 31  is a side cross-sectional view of an alternative embodiment of a heat treatment apparatus with a loop shaped electrode in a contracted state for use with the methods of the present invention; 
           [0055]      FIG. 32  is a side cross-sectional view of the apparatus of  FIG. 31  with the electrode in an expanded state within a bronchial tube for use with the methods of the present invention; 
           [0056]      FIG. 33  is a side cross-sectional view of an alternative embodiment of the invention with a plate shape electrode in a contracted state for use with the methods of the present invention; 
           [0057]      FIG. 34  is an end view of the apparatus of  FIG. 33  in the contracted state; 
           [0058]      FIG. 35  is a side cross-sectional view of the apparatus of  FIG. 33  with the plate shaped electrodes in an expanded configuration; and 
           [0059]      FIG. 36  is an end view of the expanded apparatus of  FIG. 35  for use with the methods of the present invention; 
           [0060]      FIG. 37  is a side cross-sectional view of a body conduit and an apparatus for treating the body conduit according to the present invention; 
           [0061]      FIG. 38  is a schematic side view of lungs being treated with a treatment apparatus in accordance with one aspect of the present invention; 
           [0062]      FIG. 39  is a side cross-sectional view of a distal end of an embodiment of a treatment apparatus for use with the methods of the present invention; 
           [0063]      FIG. 40  is a side cross-sectional view of a distal end of another embodiment of a treatment apparatus for use with the methods of the present invention; 
           [0064]      FIG. 41  is a side cross-sectional view of a distal end of a further embodiment of a treatment apparatus for use with the methods of the present invention; 
           [0065]      FIG. 42  is a side cross-sectional view of another embodiment of a treatment apparatus for use with the methods of the present invention; 
           [0066]      FIGS. 43A and 43B  are side views of two variations of an embodiment of a treatment apparatus having a plurality of wire shaped electrodes for use with the methods of the present invention; 
           [0067]      FIG. 43C  is a cross-sectional side view of another variation of a treatment apparatus having a plurality of wire shaped electrodes for use with the methods of the present invention; 
           [0068]      FIG. 44  is a side view of another embodiment of a treatment apparatus with electrodes positioned on expandable balloons for use with the methods of the present invention; 
           [0069]      FIG. 45  is a perspective view of an embodiment of a treatment apparatus with electrodes positioned in grooves for use with the methods of the present invention; 
           [0070]      FIG. 46  is a perspective view of an embodiment of a treatment apparatus with electrodes in a biasing element for use with the methods of the present invention; 
           [0071]      FIG. 47  is a perspective view of an embodiment of a treatment apparatus with electrodes and a biasing element for use with the methods of the present invention; 
           [0072]      FIG. 48  is a side view of an embodiment of a treatment apparatus in an unexpanded position for use with the methods of the present invention; 
           [0073]      FIG. 49  is a side view of the treatment apparatus of  FIG. 48  in an expanded position; 
           [0074]      FIG. 50  is a side view of an embodiment of a treatment apparatus in an expanded position for use with the methods of the present invention; 
           [0075]      FIG. 51  is a side view of an embodiment of a treatment apparatus having a plurality of lumens containing electrodes for use with the methods of the present invention; 
           [0076]      FIG. 52  is a side view of an embodiment of a treatment apparatus having electrodes exposed by cut away sections of a tube for use with the methods of the present invention; 
           [0077]      FIG. 53  is a side cross-sectional view of an embodiment of a treatment apparatus with electrodes positioned on an expandable balloon for use with the methods of the present invention; 
           [0078]      FIG. 54  is a schematic side view of an embodiment of a treatment apparatus with a balloon for heating of tissue for use with the methods of the present invention; 
           [0079]      FIG. 55  is a side cross-sectional view of another embodiment of a treatment apparatus for treatment with heated fluid; 
           [0080]      FIG. 56  is a side view of a treatment apparatus having a cryoprobe for use with the methods of the present invention; 
           [0081]      FIG. 57  is a cross-sectional view of an embodiment of a treatment apparatus that includes a brush for with the methods of the present invention; 
           [0082]      FIG. 58  is a side cross-sectional view of the device illustrated in  FIG. 57  after it has treated the airway of a lung; 
           [0083]      FIG. 58A  is a cross-sectional view of the device illustrated in  FIG. 58  taken along the line  58 A- 58 A of  FIG. 58 ; 
           [0084]      FIG. 59  is a side cross-sectional view of a treatment apparatus that includes a device for cutting or slicing the tissue of an air way of a lung in accordance with methods of the present invention; 
           [0085]      FIG. 60  illustrates a partial side cross-sectional view of the embodiment illustrated in  FIG. 9 , where the treatment apparatus has treated the tissue of the lung; 
           [0086]      FIG. 60A  is a cross-sectional view of the device illustrated in  FIG. 60  taken along the line  60 A- 60 A of  FIG. 60 ; 
           [0087]      FIG. 61  is a side cross-sectional view of another embodiment of a treatment apparatus, where the treatment apparatus includes a plurality of members for slicing or cutting the air way of a lung in accordance with the methods of the present invention; 
           [0088]      FIG. 62  illustrates the treatment apparatus of  FIG. 61  in a deployed position; 
           [0089]      FIG. 62A  is a cross-sectional view of the device illustrated in  FIG. 62  taken along the line  62 A- 62 A of  FIG. 62 . 
           [0090]      FIG. 63  illustrates a further embodiment of a treatment apparatus where the treatment apparatus includes a plurality of pins that puncture or penetrate the air way of a lung in accordance with the methods of the present invention; 
           [0091]      FIG. 64  illustrates the treatment apparatus of  FIG. 63  in a deployed position; 
           [0092]      FIG. 64A  is a cross-sectional view of the device illustrated in  FIG. 64  taken along the line  64 A- 64 A of  FIG. 64 ; 
           [0093]      FIG. 65  illustrates an alternative embodiment of the treatment apparatus illustrated in  FIGS. 63 and 64  for use with the methods of the present invention; 
           [0094]      FIGS. 66-70  illustrate embodiments of treatment apparatus that deliver a fluid to the airway to treat the lungs in accordance with the methods of the present invention; 
           [0095]      FIG. 71  is a side view of a bronchoscope that may be used to deploy the above-illustrated treatment apparatus when practicing the present invention; and 
           [0096]      FIG. 72  is a cross-sectional view of the device illustrated in  FIG. 71  taken along the line  72 - 72  of  FIG. 71 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0097]    In the following description, like reference numerals refer to like parts. 
         [0098]      FIG. 3  illustrates human lungs  20  having a left lung  30  and a right lung  32 . A diseased portion  31  is located at the lower portion or base of the left lung  30  (indicated by the volume of the lung below the dashed line on the left lung). In some cases, the diseased portions of an unhealthy lung are not generally located in discrete areas. That is, the diseased portions may not be distributed heterogeneously, and are more homogeneous. 
         [0099]    As illustrated in  FIG. 3 , the trachea  22  extends down from the larynx and conveys air to and from the lungs. The trachea  22  divides into right and left main bronchi  24 , which in turn form lobar, segmental, and sub-segmental bronchi or bronchial passageways. Eventually, the bronchial tree extends to the terminal bronchiole. At the terminal bronchiole, alveolar sacs  26  contain alveoli  28  that perform gas exchange as humans inhale and exhale. 
         [0100]      FIG. 4  illustrates an airway  25  of the lung  30  in greater detail. The airway  25  is a bronchial tube, air passage, lumen, bronchial airway, or respiratory bronchiole of the lung  30 . The airway  25  includes smooth muscle tissue that helically winds around the bronchiole to define a duct of the airway  25  through which air may be inhaled and exhaled during operation of the lung. The smooth muscle tissue is arranged around the airways in a generally helical pattern with pitch angles ranging from about −30 to about +30 degrees. As the airway  25  branches deeper into the lung, more and more alveolar sacs  26  and alveoli  28  appear, as shown in  FIGS. 3 and 4 . 
         [0101]      FIG. 5  illustrates a light microscopic cross-section of the tissue of the airway  25 , which is a collection of cells and intercellular substances that surround the cells, together defining the airway  25 . The airway  25  defines an airway duct  40  through which gases are inhaled and exhaled. The airway  25  of  FIG. 5  is a medium sized bronchus having an duct diameter DI of about 3 mm. The airway  25  includes a folded inner surface or epithelium  38  surrounded by stroma  32  and the smooth muscle tissue  27 . The airway  25  also has mucous glands  34  and cartilage  30  surrounding the smooth muscle tissue. Nerve fibers and blood vessels  36  also surround the airway. Hence, as shown in  FIG. 5 , the smooth muscle tissue  27  is part of the overall tissue of the airway  25 . 
         [0102]    Referring again to  FIG. 3 , the diseased portion  31  of the lung  30  is located at the lower portion or base of the lung. By way of example, it can be considered that this diseased portion  31  has been stricken by emphysema. The emphysematous portion  31  of the lung  30  generally includes sections in which the walls between the adjacent alveoli  28  have deteriorated to a degree that the lung tissue looks like Swiss cheese in cross section. When this occurs, pulmonary function is impaired to a great degree. 
         [0103]    The pulmonary system utilizes two simple mechanisms, air exchange into and out of the lungs  30  and gas exchange into and out of the blood. In patients with emphysema, both of these mechanisms are impaired, leading to dyspnea (shortness of breath), limitations in physical activities, and increased incidence of related diseases. To improve their condition, either or both of these impairments need to be improved. One way to address this is by restoring some of the lost air exchanging ability. 
         [0104]    Air exchange is created by movement of muscles that increase and decrease the pressures around the lungs. Inspiration occurs when a decrease in pressure around the lungs to below atmospheric pressure expands the lungs, which in turn causes the pressure in the terminal end points of the airways (the alveoli  28 ) to drop below atmospheric. This pulls the air into the alveoli  28  through the ‘conducting airways  25 . 
         [0105]    Exhalation is a passive process. Normal exhalation occurs when the muscles relax, allowing the natural elasticity of the lung structure to expel the air from within. In addition to making up the driving force to expel air from the lungs, the elasticity also mechanically helps keep conducting airways from collapsing. It is the-loss of elasticity of lung tissue that leads to the condition known as “dynamic airway collapse”. 
         [0106]    In more detail, airway obstruction in the emphysematous patient has two components, “small airways disease” and dynamic airway collapse of the mid-sized airways. Both contribute to the patient&#39;s inability to get adequate amounts of air to and from the alveoli  28 , which are the gas exchanging membranes in the lungs. Small airways disease is primarily caused by mucous plugging and inflammation of the small (less than 2 mm in diameter) airways, whereas dynamic airway collapse of the mid-sized airways (3 mm-6 mm) is mechanical in nature. 
         [0107]    The mechanics of mid-size airway “patency” are dictated by four forces being in balance with one another. If the balance of those forces shifts, airway collapse will occur. Specifically, these forces are: (1) air pressure inside the airway in question, (2) air pressure in the alveoli directly surrounding that airway, (3) “tethering” of the airway by the surrounding tissue (parenchyma) and (4) stiffness of the airway wall itself. It is inherent in the movement of gases within the lungs that the pressure in the alveoli  28  directly surrounding the airway  25  must be higher than that within the airway itself during exhalation. Otherwise, no air would move from the alveoli  28  to, and through, the airway  25  on its way out of the lung. Since this inherent pressure differential would collapse an airway  25  if that airway were made of a very flexible material, there must be some mechanical strength built into the airway system to oppose this collapse in healthy people. This strength comes from both the stiffness of the airway wall and the tethering action of the surrounding parenchyma. 
         [0108]    In patients with emphysema, the number of parenchymal tethers touching each airway is reduced. This in turn reduces the tethering forces that maintain the airway open. With these tethering forces reduced, the only thing keeping the airway open is the stiffness of the airway wall. In an emphysematous lung, this is often not enough, and the airways collapse during exhalation. Embodiments of the present invention aim to increase the strength of the airway walls to keep the airway open, which will increase gas exchange. 
         [0109]    By strengthening the airway walls of an emphysematous lung, the balance of forces during exhalation is shifted back toward keeping the airways open. In short, stiffening the airway wall helps prevent airway collapse during exhalation, which will thus result in an increase in airflow and gas exchange. 
         [0110]    One way to achieve this stiffening is to thicken the walls themselves. The present invention is based in part on the discovery that the airway  25  is strengthened because of the natural formation of fibrotic tissue, such as scar tissue, in response to trauma or injury. Fibrosis is the formation of fibrous or fibrotic tissue as a reparative or reactive process, i.e., regrowth of tissue after injury. The formation of fibrotic tissue essentially deposits additional tissue to the airway, which strengthens the wall of the airway. This stimulation of additional material will increase the thickness of the airway wall, thus strengthening the airway to help prevent the airway from collapsing during exhalation. The airway  25  is stiffened because the fibrotic tissue is thicker than the previous diseased tissue supporting the airway. As described below, the trauma can be caused by damaging the airway tissue, such as by delivering heat to the airway and/or by mechanical insult to the airway tissue. 
         [0111]    By strengthening the airway walls of an emphysematous lung in accordance with the embodiments of the present invention, the balance of forces during exhalation is shifted back toward keeping the airways open. Stiffening airway wall by stimulating the deposition of fibrotic tissue helps prevent airway collapse during exhalation, and will thus result in an increase in airflow. In general, the greater the scarring or injury, the greater the build-up of fibrotic tissue. The thicker the airway wall due to build-up of fibrotic tissue, the less likely that it will collapse as it may have prior to treatment according to the present invention. 
         [0112]    If the airway tissue is injured to such an extent that the airway wall thickens, it is preferable not to create so much fibrotic tissue that the airway closes. That is, it is preferable that the formation of fibrotic tissue does not cause stenosis. Stenosis may be prevented by controlling the extent of injury or damage to the airways of the lung. It is also preferable not to ablate or vaporize large amounts of airway tissue such that the airway loses its structure. Hence, it is preferable to damage enough airway tissue to cause fibrotic tissue to develop and stiffen the existing airway wall, rather than completely destroying the existing airway wall to define a new cavity, and rather than destroying so much tissue that a mass of scar tissue blocks the airway. 
         [0113]    The gas exchange of the lung  30  can also be increased in accordance with the embodiments of the present invention by destroying the airway smooth muscle tone. Smooth muscle tone refers to ability of the smooth muscle of the airway to respond to signals that trigger the airway smooth muscle to continually and partially contract. By destroying the smooth muscle or disrupting the smooth muscle&#39;s ability to respond to such signals, the contraction force is removed and the airway will become larger. 
         [0114]    When one inhales, the pressure in the airway is higher than the alviolar pressure that acts on the outside of the airway. This being the case, a “floppy” or diseased airway will remain open on inspiration. However, as described above, upon expiration, the alviolar pressure builds and at some point exceeds the air pressure in the airway. In this state, a floppy airway will be more prone to collapse and inhibit the flow of air out of the alveoli. The smooth muscle tone may further restrict the airway diameter. Hence, the removal or destruction of at least some of the smooth muscle tone will beneficially increase gas exchange during the expiration cycle. 
         [0115]    Thus, the present invention strives to relieve the effects of emphysema and other forms of pulmonary disease by increasing the efficiency of gas exchange in the lung  30 . Generally speaking, this may be achieved by inserting an apparatus into an airway of the lung through the trachea  22 , and then damaging tissue of the airway  25  to cause fibrosis to strengthen the airway and/or to destroy smooth muscle tone of the airway. 
         [0116]    The following description of the treatment apparatus for use with the embodiments of the present invention can be employed to treat a bronchial tube regardless of whether the tube lumen has collapsed or not. Specifically, the devices can be used to treat bronchial tubes that have not collapsed, are partially collapsed, or are fully collapsed. Moreover, bronchial tubes may exhibit different degrees of closure depending on the state of respiration. For example, a bronchial tube may have a fully expanded lumen during inhalation but partially or completely closed during exhalation. 
         [0117]      FIG. 6  is a schematic view of the lung  32  being treated with a treatment apparatus  40  in accordance with a method of the present invention. The preferred apparatus  40  is an elongated member that may be electronically or manually controlled by a surgeon or controller  42  to damage lung cells to cause fibrosis to stiffen the airway and/or to destroy smooth muscle tone of the airway so as to increase gas exchange performed by the lung. As described further below, the damaging of cells of airway tissue and/or destruction of smooth muscle tone of the airway with the apparatus  40  may be accomplished by any one of, or combinations of, the following: 
         [0118]    (1) heating the tissue; 
         [0119]    (2) cooling the tissue; 
         [0120]    (3) delivering a liquid that damages the tissue; 
         [0121]    (4) delivering a gas that damages the tissue; 
         [0122]    (5) puncturing the tissue; 
         [0123]    (6) tearing the tissue; 
         [0124]    (7) cutting the tissue; 
         [0125]    (8) applying ultrasound to the tissue; 
         [0126]    (9) applying ionizing radiation to the tissue; 
         [0127]    (10) other methods that cause trauma to lung cells to cause fibrosis to stiffen the airway so as to increase gas exchange performed by the lung; and 
         [0128]    (11) other methods that destroy smooth muscle tone of the airway so as to increase gas exchange performed by the lung. A more detailed description of the methods of stiffening the airway  25  and destroying the airway smooth muscle tone to increase gas exchange follows. 
         [0129]      FIG. 6A  is a representational cross-sectional view of the airway  25  of the lung  32  during expiration before it has been treated with the apparatus  40 , while  FIG. 6B  is a representational cross-sectional view of the airway  25  during expiration after it has been treated with the apparatus  40  in accordance with a preferred method of the present invention  FIG. 6B . 
         [0130]    As illustrated in  FIG. 6A , the airway  25  is partially collapsed due to pulmonary disease, such as described earlier. In this state, air exchange is adversely affected. In  FIG. 6B , the treatment apparatus  40  has damaged the tissue of the airway  25  so as increase the thickness of the airway wall. More particularly, the airway  25  has been strengthened because of the natural formation of fibrotic tissue in response to trauma or injury. The formation of the fibrotic tissue has deposited additional tissue to the airway, which strengthens the wall of the airway. Thus, the airway wall shown in  FIG. 6B  is thicker than the airway wall shown in  FIG. 6A . This increased thickness of the airway wall strengthens the airway to help prevent the airway from collapsing during exhalation. Accordingly, the airway illustrated in  FIG. 6B  is not collapsed to the same extent as the untreated airway illustrated in  FIG. 6B . Hence, if the lung  32  is stricken with emphysema, the previously described balance of forces during exhalation is shifted back toward keeping the airway  25  open, which helps prevent airway collapse during exhalation, and will thus result in an increased airflow and gas exchange. 
         [0131]      FIGS. 7-70  illustrate embodiments of treatment apparatus or devices  40 A- 40 AX that can be used to destroy airway smooth muscle tone and/or damage airway tissue to induce fibrosis according to the present invention. These are just some of the examples of the type of treatment apparatus which may be used to perform the methods according to the present invention. It should be recognized that each of the treatment apparatus described below can be modified to deliver or remove energy in different patterns, depending on the treatment to be performed. The treatment apparatus may be actuated continuously for a predetermined period while stationary, may be pulsed, may be actuated multiple times as they are moved along an airway, may be operated continuously while moving the treatment apparatus in an airway to achieve a “painting” of the airway, or may be actuated in a combination of any of these techniques. The particular energy application pattern desired can be achieved by configuring the treatment apparatus itself or by moving the treatment apparatus to different desired treatment locations in the airway. 
         [0132]      FIG. 7  is a schematic side view of lungs being treated with a treatment apparatus  40 A in accordance with one embodiment of the present invention. The treatment apparatus  40 A is an elongated member for delivery of energy from an energy source  50  to a treatment site  52  at an airway of the lungs. The energy may be delivered by the treatment apparatus  40 A in a variety of treatment patterns to achieve a desired response. Examples of patterns are discussed in further detail below. The energy which is delivered by the treatment apparatus  40 A may be any of a variety of types of energy including, but not limited to, radiant, laser, radio frequency, microwave, heat energy, or mechanical energy (such as in the form of cutting or mechanical dilation). In addition, the delivery of laser or light energy may be in conjunction with the delivery of a photodynamic agent, where the laser or light energy stimulates the photodynamic agent and initiates a cytotoxic, or cell damaging chemical reaction. 
         [0133]    The airway smooth muscle tone can be destroyed and the cells of the airway tissue of the airway  25  can be damaged by exposing the tissue  27  to energy. The damaging of the airway tissue by energy will induce fibrosis so as to strengthen the airway. A pattern for treatment can be chosen from a variety of patterns including longitudinal stripes, circumferential bands, helical stripes, and the like as well as spot patterns having rectangular, elliptical, circular or other shapes. The size, number, and spacing of the treatment bands, stripes, or spots are chosen to provide a desired clinical effect of strengthening the airway wall or destroying the smooth muscle tone of the airway without completely destroying the airway or obstructing the airway. 
         [0134]      FIG. 8  illustrates another treatment apparatus  408  for use with one embodiment of the present invention. The treatment apparatus  408  includes an elongated, cylindrical member  90  having a heating element that has a plurality of electrodes designated  92  and  94  located on the outer surface of the member. The electrodes are electrically connected to a source of RF energy via connector  98 . Preferably each electrode is configured as a band as shown that has a width of about 0.2 mm to about 3 mm, and preferably each electrode band is separate from the next by a distance of about 0.5 mm to 10 mm. The heating element may include one or more electrode bands. The treatment apparatus  408  has a distal end  100  that is rounded to reduce the amount of resistance encountered when the apparatus is advanced into the airway  25 . 
         [0135]    The apparatus  408  has an outer diameter that is approximately equal to (or can be expandable to equal) the desired final inner diameter of the lumen of an air passage to be treated. Typically, the outer diameter ranges from about 1.3 mm to about 7 mm. When the heating element comprises a plurality of electrode bands, the distance between each band is preferably less than about three times the outer diameter of the apparatus. The effect will be that the patency bands formed on the wall of the lumen by the electrodes  92 ,  94  will be separated from each other by no more than a distance equal to about three times the length of the outer diameter of the lumen. The patency bands so configured will provide good support for the airway  25  to prevent the lumen from collapsing. 
         [0136]    The treatment apparatus  408  applies a sufficient amount of energy to the walls of collapsible air passages  25  to destroy airway smooth muscle tone and damage cells of the airway tissue to induce fibrosis and create a more rigid wall that can support a non-collapsed lumen. In this embodiment, energy emanates from the electrode bands  92 ,  94 , so that following treatment with this particular apparatus, the walls of the air passage  25  will develop patency bands corresponding to locations along the walls. The contours of the patency bands should substantially match those of the electrode bands. As is apparent, the number and width of each electrode band are not critical. In the case where there is only one electrode band, it may be necessary to move the apparatus and heat more than one area of the lumen wall in order to damage sufficient amounts of the airway wall to induce enough fibrosis to increase the strength of the airway wall such that it is no longer collapsed, i.e., the lumen remains substantially open during normal breathing. 
         [0137]    When the treatment apparatus  408  is positioned at the treatment site, an RF generator is activated to provide suitable RF energy, preferably at a selected frequency in the range of 10 MHZ to 1000 MHZ. The emitted energy is converted within the tissue into heat in the range of about 40° C. to about 95° C. 
         [0138]    RF energy is no longer applied after there has been damage to the tissue to induce a healing response. Preferably, the RF energy is applied for a length of time in the range of about 1 seconds to about 120 seconds. Suitable RF power sources are commercially available and well known to those skilled in the art. In one embodiment the RF generator employed has a single channel, delivering approximately 1 to 25 watts of RF energy and possessing continuous flow capability. The rate of transformation can be controlled by varying the energy delivered to the heating element. 
         [0139]    Besides using RF energy for energizing the heating element, it is to be understood that other forms of energy such as alternating current, microwaves, ultrasound, and light (either coherent (e.g., laser) or incoherent (e.g., light emitting diode or tungsten filament) can be used), and that the thermal energy generated from a resistive coil, a hot fluid element (e.g., circulating liquids, gases, combinations of liquids and gases, etc.), a curie point element, or similar elements can be used as well. The hot fluid element may comprise, for example, an elongated member similar to the one illustrated in  FIG. 8  that includes a conduit system whereby heated fluid is transported through the center of the member and then channeled outward toward the inner surface of the member. In one embodiment the heated fluid is diverted to contact the inner surface of the elongated member so that energy radiates from selected areas on the outer surface of the member corresponding to areas  92  and  94  in  FIG. 8 . Regardless of the source, energy delivered to the lumen wall of the obstructed airway passage should be such that all of the airway tissue is not completely ablated. 
         [0140]    The heating element, as shown in  FIG. 8 , operates as a unipolar, internal electrode in the patient&#39;s body. An outer electrode (not shown) having a much larger surface area than that of the electrode bands is placed on the outer surface of the patient&#39;s body. For example, an external metal mesh or solid plate is placed on the skin with conductive gel. Both electrodes are connected to an RF generator which produces an electric field at a high frequency within the patient&#39;s body. Because the collective surface area of the electrode bands is much smaller than that of the outer electrode, the density of the high frequency electric field is much higher around the electrode bands. The electric field reaches its highest density between the two electrodes in the region near the heating element. The increased density of the field around the electrode bands produces localized heating of the tissue of the lumen wall. 
         [0141]    A heating element comprising a bipolar electrode can also be used. Referring to  FIG. 8 , in a bipolar arrangement electrode band  92  would be a first conductive element and electrode band  94  would be a second conductive element. 
         [0142]    The electrode bands emit RF energy with the first conductive element acting as the active electrode and the second conductive element acting as the return electrode, or vice versa. One electrode would be connected to the positive electrode of the generator and the other would be connected to the negative electrode. An insulator  96  is located between the conductive elements.  FIG. 9  illustrates another treatment apparatus  40 C for use with another embodiment of the present invention. The treatment apparatus  40 C includes a heating element having multiple, i.e., double, bipolar electrode bands. Bands  91  are connected to the positive electrode of the RF generator and bands  93  are connected to the negative electrode. The material between the conductive elements are electrically insulated. 
         [0143]    While the heating elements have been shown as electrode bands, other configurations can be used such as, for example, spiral, ring and grid patterns. These elements will create corresponding patterns on the lumen wall. 
         [0144]      FIG. 10A  illustrates another embodiment of the treatment apparatus  40 D for use with another embodiment of the present invention. The treatment apparatus  40 D includes an elongated, cylindrical member having a heating element that comprises electrodes  106  and  104  located on the other surface of the member. Preferably, the heating element comprises a bipolar electrode wherein one of the electrodes is the active electrode and the other electrode is the return electrode, or vice-versa. One electrode is connected to the RF positive electrode of the generator and the other is connected to the negative electrode. Segment  108  of the member situated between the electrodes is made of electrically insulating material. 
         [0145]    The segment of elongated member in and around electrode  104  is fabricated of material that is expandable and substantially impervious to air or other suitable gases for causing the elongated member to balloon. In this fashion, this section of the elongated member is radially expandable and deformable in response to compressed gas or any other suitable force or material that is applied into the interior region of the elongated member. Moreover, the elongated member will substantially return to its original, non-expanded form when the internal force is deactivated or the material is withdrawn.  FIG. 10B  illustrates the elongated member in the expanded position. The degree of expansion or distance that the member expands will depend on, among other things, the pressure applied and the elasticity of the member wall. In this embodiment, material between position  102  on the elongated member to the base of electrode  106  is fabricated from expandable material such as latex or polyethylene. The material selected preferably does not melt at the temperature ranges used in the treatment. Radial expansion causes electrode  104  to come into thermal or electrical contact with tissue of the air passage  25  to be treated. Electrode  104  is preferably a spring coil. The treatment apparatus  400  may comprise more than one such coil electrode, which may be positioned along the length of the elongated member so that a plurality of locations along a bronchial tube can be treated simultaneously. 
         [0146]      FIGS. 11A ,  11 B,  12 A and  12 B illustrate a further embodiment of the treatment apparatus  40 E for use with an embodiment of the present invention. The treatment apparatus  40 E includes an elongated, cylindrical member  110  having one or more electrodes  112  situated on the outer surface of the elongated member. Preferably, a plurality of these electrodes form a number of rows of electrodes that are positioned along the length of the elongated member. As shown in cross sectional view  FIG. 12A , the segment of surface of the elongated member at and around the electrodes is arranged in pleats  114 . By being folded in this manner, the surface can expand radially when an outward force is applied from the interior of the cylindrical member as shown in  FIGS. 12A and 12B . In this embodiment, the electrodes comprise non-ferrous (e.g., aluminum) strips and an electromagnet  114  which is positioned in the interior of the elongated member. When the electromagnetic is energized with alternating current the magnetic field will cause the non-ferrous electrodes to repel from the electromagnet. In addition, the temperature of the electrode will rise due to Joule heating. The treatment apparatus may comprise a plurality of rows of the electrodes. 
         [0147]      FIG. 13A  illustrates another embodiment of a treatment apparatus  40 F for use with another embodiment of the present invention. The treatment apparatus  40 F includes a balloon  128  placed at the distal end of a catheter shaft  122 . The catheter shaft is connected to syringe  124  located at the proximal end and is connected to an RF generator  126  in between the syringe and balloon. As shown in  FIG. 13B  which is an enlarged, cut away view of the device, the balloon  128 , which is illustrated in the non-inflated state, is constructed of an elastomeric material  144 . A preferred elastomeric material is silicone. Extending from lumen  146  of the shaft and into the interior of the balloon are electrodes  140  and  142  which are spaced apart and supported by rod  145 . In this embodiment, each electrode is configured as a loop or ring around the rod. Catheter shafts suitable for use in the present invention are substantially any of the catheter shafts in current clinical use for surgical procedures. Balloons suitable for the present invention may be of similar material and design as those currently being used in percutaneous transluminal angioplasty. For a review of the state of the art, see U.S. Pat. Nos. 4,807,620; 5,057,106; 5,190,517; 5,281,218; 5,314,466; 5,370,677; 5,370,678; 5,405,346; 5,431,649; 5,437,664; 5,447,529; and 5,454,809, the disclosures of which are all incorporated herein by reference. The inventive heat treatment apparatus will be described using balloons that are fabricated from an elastomeric material such as, for instance, silicone, natural latex, and polyethylene. The material selected preferably does not melt at the temperature ranges used in the treatment and is preferably impervious to the fluid used to inflate the balloon. With balloons that are made of elastomeric materials, the degree of expansion is proportional to the amount of force introduced into the interior of the balloon. Moreover, the balloon preferably will substantially return to its original, non-expanded form when the internal force is deactivated. When the balloon is fully expanded, its diameter will preferably be about 1 mm to 30 mm depending on the site to be treated. The balloon is typically attached to the catheter tip and the balloon material is folded or collapsed so that when it is fully inflated the balloon diameter has a fixed dimension. It is understood however that other balloon structures can be employed. For example, balloons made of non-elastic materials such as, for example, polyester (e.g., MYLAR) and polyethylene, can also be used. As is apparent, the balloon serves as a vessel or reservoir for medium that is heated. In the case where the electrodes are bipolar electrodes, the fluid (e.g., saline) between the poles acts as a resistive heating medium or resistive element. In addition, the balloon upon being inflated serves as structural support for the bronchial tubes. 
         [0148]    Referring to  FIGS. 13A and 13B , electrodes  140  and  142  are connected via cables  136  and  138 , through the wall of the balloon  128 , and through the catheter shaft  122  to a radio frequency (RF) generator  126  with controls  130 . The catheter shaft  122  is also connected to the syringe  124  or other similar device for forcing a noncompressible fluid, such as saline, from source  134  through valve  132  to inflate the balloon with the fluid as the operating surgeon deems appropriate. 
         [0149]    The frequency range of RF radiation useful in the present invention is typically about 10 KHZ to about 100 MHZ and preferably in the range of about 10 KHZ to about 800 KHZ. However, frequencies outside this range may be used at the discretion of the operating surgeon. Alternatively, microwave radiation typically in the frequency range of about 1,000 MHZ to about 2,000 MHZ, preferably in the range of about 1,100 MHZ to about 1,500 MHZ, may be used in place of RF radiation. However, as above, frequencies outside this range may be used at the discretion of the operating surgeon. The RF generator  126  may be replaced with a microwave generator, and the cables  136  and  138  replaced with a waveguide. Other modifications familiar to those skilled in the art may also be required. In addition, alternating current can be employed. 
         [0150]    In use, when the operating surgeon has placed the treatment apparatus with the collapsed balloon within the lumen of a bronchial tube to be treated, the balloon is inflated through the catheter shaft  122  with fluid from the syringe  124  located conveniently for the surgeon. In the case where the lumen of the bronchial tube has collapsed or is partially collapsed, the balloon is preferably inflated until the lumen has expanded to its normal diameter with the balloon in substantial contact with the inner surface of the lumen. Alternatively, in the case where the lumen has not collapsed, the balloon is preferably inflated until it is in substantial contact with the inner surface of the lumen. Indeed, inflation of the balloon is not necessary in treating a non-collapsed bronchial lumen which has a diameter that is about equal to, or less than that of the outer surface of the uninflated balloon. As is apparent, even if the balloon does not have to be inflated, the balloon interior has fluid, e.g., electrically conductive saline, present which becomes heated by the application of RF energy. 
         [0151]    Preferably, the exact amount of inflation is determined by the operating surgeon who monitors the balloon expansion by means of endoscopy, or other suitable imaging methods of the art. Generally, the heat required is induced in the tissue of the bronchial tube wall by the RF or microwave radiation emitting from the balloon tip. 
         [0152]      FIGS. 14A ,  14 B,  15 A,  15 B,  16 A,  16 B,  17 A, and  17 B illustrate other embodiments of the electrode configurations which can be employed with the treatment apparatus  40 F shown in  FIG. 13A . In these figures, the balloons are shown in the inflated state containing fluid  151 . The arrows depict the path of the electric field between the two electrodes or probes that serve as RF poles in the manners described above. 
         [0153]    In  FIG. 14A , which is a cross-sectional view of balloon  150 , electrodes  152  and  154  are configured as elongated wires that are attached at opposite sides of nonconductive rod  156 .  FIG. 14B  is a side view of the balloon with the electrodes inside the interior of the balloon which is sealed except for conduit  158  through which fluid  151  (e.g., saline) is introduced and removed. 
         [0154]    In  FIG. 15A , which is a cross-sectional view of the balloon  160 , electrodes  162  and  164  are wires each configured as a semi-circle and positioned at opposite sides of each other to form a circle. The electrodes have opposite polarities and are electrically insulated from each other.  FIG. 15B  is a side view of the balloon with the electrodes inside the interior of the balloon which is sealed except for conduit  168  through which fluid  151  is introduced and removed. 
         [0155]    In  FIG. 16A , which is cross-sectional view of the balloon  170 , electrodes  172  and  174  are wires with tips that protrude into the interior region of the balloon which has a hollow disk or horse shoe configuration with partition  176  separating the two halves of the disk. Fluid  151  is introduced and removed from the balloon through conduit  178  in support member  175 . The electrodes remain stationary in the solid regions of support member  175  as shown in side view  FIG. 16B . 
         [0156]      FIGS. 17A and 17B  illustrate another embodiment in which the balloon  180  is fabricated of an electrically conductive material and therefore also serves as an electrode. In this fashion, one of the electrodes is an integral part of the balloon itself. The second electrode  182  is attached to non-conducting rod  186 .  FIG. 17B  is a perspective view of the balloon with electrode  182  in the interior of the balloon which is sealed except for conduit  188  through which fluid  151  is introduced and removed. Suitable electrically conductive materials for fabricating the balloon in this case include, for example, a polyester film (e.g. MYLAR) that is coated with gold, silver, or platinum. 
         [0157]      FIG. 18  illustrates another embodiment of the treatment apparatus  40 G for use with one embodiment of the present invention. With the treatment apparatus  40 G, the heat generated to heat the fluid in the balloon is supplied by a circulating, hot fluid. Referring to  FIG. 18 , a balloon  190  (substantially the same as balloon  128  of the embodiment shown in  FIG. 13A ) is attached to a catheter  192  containing a smaller, coaxial catheter  194  (coaxial catheter  194  is substantially the same as catheter  192 , differing only in size.) A heated fluid  198 , which may be a liquid, such as water or physiologically compatibly saline solution, is pumped by a metering, circulating pump  202 , through a heating unit  200 , then through the outer catheter  192  to the balloon. The fluid heats the surface of the balloon and exits through the inner coaxial catheter  194  to return to the pump. A positive pressure is maintained within the system to keep the balloon at the proper inflation. This embodiment is employed in substantially the same manner as the other embodiments described above regarding its use to heat the airway tissue to induce fibrosis and strengthen the airway and destroy smooth muscle tone. The choice of the temperature of the circulating liquid is at the discretion of the operating surgeon, but will usually be in the range of about 60° C. to about 95° C. 
         [0158]    The treatment apparatus  40 H shown in  FIG. 19  represents another embodiment of the treatment apparatus for performing another embodiment of the present invention, wherein the heat generated to heat the fluid in the balloon is supplied by a hot fluid that is injected into the balloon. The catheter  208  includes electrodes  210  and  216  positioned in lumen  206  of the catheter. The electrodes are connected to AC generator  218  although an RF generator can also be used. The channel or lumen  206  also serves as a reservoir for liquid which is introduced from source  222  through syringe  204 . Once the fluid is heated to the desired temperature, it can be injected into the interior of the balloon. As is apparent, the fluid serves both to inflate the balloon as well as to supply the heat treatment of the bronchial tube. A positive pressure is maintained within the system to keep the balloon at the proper inflation. Instead of using resistive heating, the fluid can be heated with heat exchanger  208 . 
         [0159]    Preferably, the RF energy is applied for a length of time in the range of about 1 second to about 600 seconds and preferably about 5 to about 120 seconds. Suitable RF power sources are commercially available and well known to those skilled in the art. In one embodiment the RF generator employed has a single channel that is capable of delivering approximately 1 to 100 watts and preferably 1 to 25 watts of RF energy and possesses continuous flow capability. Regardless of the source of energy used during treatment, the lumen or the bronchial tube is maintained at a temperature of at least about 60° C. and typically between 70° C. to 95° C. and preferably between 70° C. to 85° C. 
         [0160]    The treatment apparatus of the present invention may include more than one balloon and attendant bipolar electrodes which are positioned along the length of the elongated member so that a plurality of locations along a bronchial tube can be treated simultaneously.  FIG. 13C  illustrates an alternative embodiment of the treatment apparatus of  FIG. 13A  described above, which includes two balloons  148 A,  148 B that are spaced apart. Each balloon  148 A,  148 B includes a suitable set of bipolar electrodes as described previously. The balloons can be connected to separate sources of fluid or they can share a common source. 
         [0161]      FIGS. 20A and 20B  show a further embodiment of the treatment apparatus  401  for use with another embodiment of the present invention. The treatment apparatus  401  includes a balloon  300 , similar to the balloons described earlier, that is positioned at or near the distal end of elongated rod  310  which is positioned within the lumen or aperture  351  of catheter sheath  350 . It is understood that the term “rod” also encompasses tubes which have hollow channels. As shown, the balloon with inner surface  301  is in the inflated state having been inflated with an appropriate fluid such as air or saline that is injected from conduit  330  and into the interior of the balloon through aperture  331  in the rod. The apparatus includes electrodes  302  and  304 , similar to those described earlier, which are spaced apart along the outer perimeter of the inflated balloon. It is understood that the number of electrodes and their configurations on the outer surface of the balloon can be varied. These electrodes come into contact with the wall of the airway  25  when the balloon is inflated. The electrodes employed in the present invention can have different configurations. For example, the electrodes can be conventional coil wires with round cross sections, or they can have a non-round configuration, such as, for example, a thin, foil or band with a rectangular cross section. For the device shown in  FIG. 20B , electrodes  302  and  304  are preferably flat bands each extending around the circumference of the balloon. To permit expansion of the balloon, each band is positioned around the outer surface of the balloon with the two ends overlapping each other. As shown the  FIG. 20B , electrode  302  is a band having ends  303  and  313  with a portion of the band adjacent to end  303  overlapping a portion of the band adjacent to end  313 . Similarly, electrode  304  is a band having overlapping ends  305  and  315 . 
         [0162]    The balloon of the treatment apparatus  401  is preferably constructed of nonelastic material that is initially folded and/or collapsed. In this non-inflated state, the diameter of the balloon is small enough that the balloon can be positioned inside an aperture or working channel of a bronchoscope. In use, the bronchoscope first is positioned at the treatment site before the balloon is exposed and then inflated. Heat treatment is then commenced to damage airway tissue to induce fibrosis and/or destroy smooth muscle tone. 
         [0163]      FIGS. 20A and 20B  show that electrodes  302  and  304  are connected via cables  322  and  342 , respectively, to a radio frequency (RF) generator  329  with controls  338 , such as described earlier. Rod  310  is also connected to syringe  350  which is employed to inject a fluid from source  346  through valve  348  into the balloon. 
         [0164]      FIG. 21  illustrates another embodiment of the treatment apparatus  40 J for use with another method of the present invention which includes a pair of electrode coils  410  and  420  that are positioned in tandem. The number of electrode coils is not critical. The apparatus also includes an elongated rod  430  which has a distal end  431  that is connected to a tip or knob  440  and has a proximal end which is at least partially slidably positioned inside aperture  451  of catheter sheath  450  that includes end coupler  435 . Coil  410  has two ends, the first end  411  being attached to knob  440  and the second end  412  is attached to rotatable or floating coupler  470 . Similarly, coil  420  has two ends, the first end  421  is attached to rotatable coupler  470  and the second end  422  is attached to end coupler  435 . 
         [0165]    As shown in  FIG. 21 , the coils are in the relaxed state which is meant that no torque is being applied to either coil. In this state, each coil has a “barrel” configuration so that the diameter of the outer contour formed by each coil is largest at its center and smallest at its two ends. A number of preferred methods can be employed to change the diameters of the contour. One method is to compress or expand the coils along the axis. For example, by pushing rod  430  outward so that knob  440  extends away from catheter sheath  450 , the coil diameters will decrease. Another method of changing the diameter is to apply torque to the coils. Torque can be applied by rotating the rod in a clockwise or counterclockwise direction while keeping end coupler  435  stationary, e.g., attached to the inner surface of catheter sheath. Torque can also be applied by keeping rod  430  stationary while rotating end coupler  435 . Alternatively, torque can be applied by rotating the rod in one direction while rotation end coupler  435  in the opposite direction. During the rotation process, rotatable coupler  470  will also rotate to thereby transfer torque from one coil to the other. 
         [0166]    In practice, applying torque to adjust the radial diameters of the coils is preferred over compressing or pulling the coils lengthwise since applying torque creates less of a gradient in the diameter of each coil. According, preferably, the treatment apparatus is constructed so that end coupler  435  remains stationary. Torque is preferably applied by manually rotating rod  430 . When more than one coil is employed, a rotatable coupler is required to connect adjacent coils. Multiple coil configurations are preferred over one with a single coil that has the same length (in the relaxed state) as the sum of the lengths of the smaller coils since the diameters of the smaller coils will tend to be more uniform and in contact with the wall of the bronchial tube being treated. Each coil in the embodiment shown in  FIG. 21  is connected to an appropriate source of energy. For example, coils  410  and  420  can be connected by lines  415  and  425  to a radio frequency generator  430  as described above. In operation, the heat treatment apparatus  40 J is positioned at the treatment site before the diameters of the coils are adjusted by applying torque. Energy is then applied to the coils. 
         [0167]      FIGS. 22 and 23  show embodiments of the heat treatment apparatus  40 K,  40 L for use with further methods of the present invention, which are similar to that of  FIG. 21 . The apparatus of  FIG. 22  includes a pair of electrode coils  510  and  520  that are positioned in tandem. The apparatus also includes an elongated rod  530  which has a distal end  531  that is connected to a tip or knob  540  and has a proximal end which is at least partially slidably positioned inside aperture  551  of catheter sheath  550  that includes end coupler  535 . Coil  510  has two ends, the first end  511  being attached to knob  540  and the second end  512  is attached to rotatable coupler  570 . Similarly, coil  520  has two ends, the first end  521  is attached to rotatable coupler  570  and the second end  522  is attached to end coupler  535 . As is apparent, each electrode has a cone-shaped contour and comprises a coil that is wound about and along the axis of the rod  530  and which in the relaxed state has a large diameter at one end and a small diameter at the other end. 
         [0168]    The treatment apparatus  40 L of  FIG. 23  includes a pair of electrode coils  610  and  620  that are positioned in tandem. The apparatus also includes an elongated rod  630  which has a distal end  631  that is connected to a tip or knob  640  and has a proximal end which is at least partially slidably positioned inside aperture  651  of catheter sheath  650  that includes end coupler  635 . Coil  610  has two ends, the first end  611  being attached to knob  640  and the second end  612  is attached to rotatable coupler  670 . Similarly, coil  620  has two ends, the first end  621  is attached to rotatable coupler  670  and the second end  622  is attached to end coupler  635 . As is apparent, each electrode has a single loop configuration that comprises a coil that is wound once about the rod  630 . In this configuration, the two electrodes when in the relaxed state preferably form loops having the same diameter. 
         [0169]    The devices  40 K,  40 L of  FIGS. 22 and 23  operate in essentially the same manner as the device  40 J of  FIG. 21 . Specifically, the same methods can be employed to adjust the radial diameter of the coils by compressing or pulling the coils or by applying torque to the coils. In addition, each coil is connected to an appropriate source of energy. For example, coils  610  and  620  can be connected by lines  615  and  625  to a radio frequency generator  330  as shown in  FIG. 20A . 
         [0170]    The electrodes may be constructed of a suitable current conducting metal or alloys such as, for example, copper, steel, and platinum. The electrodes can also be constructed of a shape memory alloy which is capable of assuming a predetermined, i.e., programmed, shape upon reaching a predetermined, i.e., activation, temperature. Such metals are well known in the art as described, for example, in U.S. Pat. Nos. 4,621,882 and 4,772,112 which are incorporated herein. For the present invention, the shape memory metal used should have the characteristic of assuming a deflection away (i.e., expands) from the elongated rod when activated, i.e., heated in excess of the normal body temperature and preferably between 60° C. and 95° C. A preferred shape memory alloy is available as NITINOL from Raychem Corp., Menlo Park, Calif. For the heat treatment apparatuses that employ coils as shown in  FIGS. 20-23 , preferably the electrodes are constructed of NITINOL in a predetermined shape and in the alloy&#39;s super elastic phase which can withstand very large deflections without plastic deformation. 
         [0171]    Alternatively, the heat treatment apparatuses employing a unipolar electrode can also be employed. For instance, in the case of the embodiment shown in  FIGS. 20A and 20B , the heating device can have one or more inner electrodes  302  and/or  304  on the balloon surface and an outer or external electrode  388  that has a much larger surface area than that of the internal electrode(s) and that is placed on the outer surface of the patient&#39;s body. For example, the external electrode can be an external metal mesh or solid plate that is placed on the skin with conductive gel. Both the internal and external electrodes are connected to an RF generator which produces an electric field at a high frequency within the balloon. Because the collective surface area of the internal electrode(s) is much smaller than that of the outer electrode, the density of the high frequency electric field is much higher around the internal electrode(s). The electric field reaches its highest density in the region near the internal electrode(s). The increased density of the field around the internal electrode(s) produces localized heating of the tissue to destroy smooth muscle tone and damage tissue to cause fibrosis, which stiffens the airway  25  so as to increase gas exchange performed by the lung. 
         [0172]    As is apparent, the heat treatment apparatus can have more than one electrode that is positioned at or near the distal end of the elongated rod. For example,  FIG. 24  depicts schematically the distal end  700  of a treatment apparatus  40 M which comprises electrodes  701 ,  702 , and  703 . In this configuration, if the device operates in the bipolar mode, two of the three electrodes (e.g.,  701  and  702 ) are connected to one pole of the RF generator and the other electrode ( 702 ) is connected to the other pole. Heat will be generated in the tissue adjacent the region between electrodes  701  and  702  and the region between electrodes  702  and  703 . These electrodes  701 ,  702 , and  703  can be attached to the exterior surface of a balloon, alternatively they represent adjustable coils in embodiments that do not require a balloon. 
         [0173]    When the treatment apparatus  40 M includes multiple electrodes, not all the electrodes need to be activated at the same time, that is, different combinations of electrodes can be employed sequentially. For example, in the case of the above described bipolar embodiment with three electrodes, electrodes  701  and  702  can be first activated to heat a section of the bronchial tube wall. During the heat treatment, electrode  703  can also be activated so that a second section of the bronchial tube wall is heat treated simultaneously. Alternatively, electrode  701  is disconnected to the RF generator before electrode  703  is activated so that the second section is treated subsequent to treatment of the first section. 
         [0174]    In addition, when a treatment apparatus  40 M includes multiple electrodes, the device can operate in the monopolar, bipolar mode, or both modes at the same time. For instance, electrodes  701  and  702  can be designed to operate in the bipolar mode while electrode  703  is designed to operate in the monopolar mode. As a further variation, the electrodes can be constructed of different materials and/or constructed to have different configurations. For example, electrode  701  can be made of a shape memory alloy and/or it can be a coil while each of the other electrodes  702  and  703  can be made of a non-shape memory material and/or it can be a band with a rectangular cross section. 
         [0175]    The treatment apparatus can comprise more than one balloon that is attached to the elongated rod. For example,  FIG. 25  depicts schematically the distal end of a treatment apparatus  40 N for use with embodiments of the present invention, which comprises balloons  810  and  820 . Electrodes  811  and  812  are attached to the exterior surface of balloon  810  and electrodes  821  and  822  are attached to the exterior surface balloon  820 . The treatment apparatus  40 N includes an elongated rod  860  which is positioned with the lumen of catheter sheath  850 . The treatment apparatus  40 N is preferably constructed in the same manner as the device shown in  FIG. 208  except for the additional balloon. Operation of the device  40 N is also similar although the surgeon has the choice of activating both sets of electrode simultaneously or one set at a time. 
         [0176]      FIG. 26  illustrates another embodiment of a treatment apparatus  40 P for use with the methods of the present invention. The treatment apparatus  40 P is introduced through a catheter, bronchoscope, or other tubular introducer member  1012 . The heat treatment apparatus includes a shaft  1014  and one or more electrodes  1016 . Electrically connected to the electrodes  1016  is an RF generator  1018  or other energy source. The RF generator is controlled by a controller  1020 . Although the invention will be described as employing an RF generator, other energy sources, such as alternating current and microwave may also be used. 
         [0177]    In accordance with the embodiment of  FIG. 26 , the electrodes include a first conical electrode  1016 A connected to an inner shaft  1022  and a second conical electrode  1016 B connected to an outer shaft  1024 . The conical electrodes  1016 A,  1016 B are positioned with their axes aligned and may be fixed or movable with respect to each other. Each of the conical electrodes  1016 A,  1016 B, includes at least two overlapping sections  1026 . The sections  1026  are flexible and overlap one another to allow the electrodes  1016 A,  1016 B to be compressed within the lumen of the catheter  1012  for insertion into the bronchial tube of a patient. Once the catheter  1012  is positioned with a distal end at a desired treatment location within the bronchial tubes, the shaft  1014  is used to push the electrodes  1016 A,  1016 B out of the distal end of the catheter. Once deployed from the catheter  1012 , the electrodes  1016 A,  1016 B expand radially outwardly until the distal ends of the electrodes contact the walls of the bronchial tube. 
         [0178]    The electrodes  1016 A,  1016 B are electrically connected to the RF generator  1018  by electrical cables  1028 ,  1030 . When the treatment apparatus  40 P employs two electrodes  1016 A,  1016 B the two electrodes are preferably oppositely charged with one of the electrodes connected to a negative output of the RF generator and the other electrode connected to a positive output of the RF generator. Alternatively, both the electrodes  1016 A,  1016 B or a single electrode  1016  may be connected to the same output of the RF generator and an external electrode  1034  may be used. The external electrode  1034  is connected to an output of the RF generator  1018  having an opposite polarity of the output connected to the internal electrode  1016 . 
         [0179]      FIG. 27  illustrates an alternative embodiment of a heat treatment apparatus  1040  having a single electrode  1016  positioned on a shaft  1014 . The electrode  1016  is shown as it is deployed from the distal end of a catheter  1012  for heat treatment of the lumen of bronchial tubes. 
         [0180]    The electrodes  1016  of the embodiment of  FIGS. 26 and 27  are formed of a suitable conductive material such as metal, plastic with a metal coating, or the like. The two or more sections  1026  of each of the cone shaped electrodes is fixed to the shaft  1014  and biased outwardly so that the sections expand or unfold to an enlarged diameter upon release from the distal end of the catheter  1012 . The electrodes  1016  preferably have an enlarged diameter which is equal to or slightly greater than an interior diameter of the bronchial tube to be treated. As shown most clearly in  FIG. 27 , the sides of the sections  1026  overlap one another even in the expanded state. 
         [0181]    In operation of the embodiments of  FIGS. 26 and 27 , the distal end of the catheter  1012  is first positioned at the treatment site by known catheter tracking methods. The catheter  1012  is then retracted over the heat treatment apparatus to expose and expand the electrodes  1016 . Each electrode  1016  of the energy emitting apparatus  40 P expands radially outward upon retraction of the catheter  1012  until the electrodes come into contact with the wall of the bronchial tube. In the embodiment of  FIG. 27 , the distance between the two energy emitting electrodes  1016 A,  1016 B may be fixed or may be changeable by sliding the inner shaft  1022  within the outer shaft  1024 . When treatment is completed the heat treatment apparatus  40 P is retracted back inside the catheter  1012  by sliding the catheter over the electrodes. As the heat treatment apparatus  40 P is retracted the sides of the sections  1026  of the electrode  1016  slide over each other upon coming into contact with a distal edge of the catheter  1012 . 
         [0182]      FIGS. 28 and 29  illustrate an alternative embodiment of a treatment apparatus  400  for use with the methods of the present invention. The treatment apparatus  400  may be delivered to a treatment site in a collapsed configuration illustrated in  FIG. 28 . The treatment apparatus  400  includes two leaf spring or wire shaped electrodes  1054 A and  1054 B. The electrodes  1054 A,  1054 B are connected to an insulating end cap  1056  of a hollow shaft  1058 . The electrodes  1054 A,  1054 B are electrically connected to the RF generator or other energy source by electric cables  1060 ,  1062 . The heat treatment apparatus  1050  is provided with a central shaft  1064  which is slid able within the hollow shaft  1058 . The central shaft  1064  has a shaft tip  1048  which is connected to a distal end of each of the electrodes  1054 A,  1054 B. 
         [0183]    Each of the electrodes  1054 A,  1054 B is preferably insulated with an insulating sleeve  1066  except for an exposed contact section  1068 . The treatment apparatus  400  is delivered to the lumen of a bronchial tube to be treated either alone or through a catheter, bronchoscope, or other channel. The electrodes  1054 A,  1054 B are expanded radially outwardly by moving the central shaft  1064  proximally with respect to the hollow shaft  1058  of the treatment apparatus  400 . Upon expansion, the exposed contact sections  1068  of the electrodes  1054 A,  1054 B come into contact with the walls of the airway or bronchial tube  8 , shown in  FIG. 29 . The electrodes  1054 A,  1054 B may be configured to bend at a predetermined location forming a sharp bend as shown in  FIG. 29 . Alternatively, the electrodes  1054 A,  1054 B may form a more gradual curve in the expanded configuration. The electrodes  1054 A,  1054 B are preferably connected to opposite poles of the energy source. Alternatively, both of the electrodes  1054 A,  1054 B may be connected to the same lead of the energy source and the external electrode  1034  may be used. Upon completion of the treatment process the electrodes  1054  are retracted back into the catheter for removal or moving to a subsequent treatment site. 
         [0184]      FIGS. 30 and 30A  illustrate another embodiment of the treatment apparatus  40 R for use with embodiments of the present invention. The treatment apparatus  40 R includes four electrodes  1054 A,  1054 B,  1054 C,  1054 D. The four electrode embodiment of  FIGS. 30 and 30A  operates in the same manner as the embodiments of  FIGS. 28 and 29  with a slidable central shaft  1064  employed to move the electrodes from a compressed configuration to the expanded configuration illustrated in  FIGS. 30 and 30A . Each electrode  1054 A- 1054 D is connected at a proximal end to the insulating end cap  1056  of the hollow shaft  1058  and at a distal end to the central shaft  1064 . Relative motion of the hollow shaft  1058  with respect to the central shaft  1064  moves the electrodes  1054  from the collapsed to the expanded position. 
         [0185]      FIGS. 31 and 32  illustrate a further embodiment of a heat treatment apparatus  40 S employing one or more wire or leaf spring shaped loop electrodes  1094 . As in the previous embodiments, the loop electrode  1094  expands from a contracted positioned within a catheter  1092  as illustrated in  FIG. 31  to an expanded position illustrated in  FIG. 32 . In the expanded position, the loop shaped electrode  1094  comes into contact with the walls of the airway or bronchial tube B. Although the embodiment of  FIGS. 31 and 32  has been illustrated with a single loop shaped electrode  1094 , it should be understood that multiple loop shaped electrodes may also be use. The loop shaped electrode  1092  is connected to the shaft  1096  of the heat treatment apparatus  40 S by an end cap  1098  and is electrically connected to the energy source by the electric cables  1100 . 
         [0186]      FIGS. 33-36  illustrate an alternative embodiment of a treatment apparatus  40 T for use with the embodiments of the present invention. The treatment apparatus  40 T includes a flexible plate shaped electrode  1114 . The flexible plate shaped electrode  1114  is substantially flower shaped in plan having a plurality of petals  1116  with curved distal ends extending from a central section  1120 . The petals  1116  flex along a hinge line  1118  to the compressed insertion configuration illustrated in  FIG. 33  in which the petals  1116  extend substantially perpendicularly from the central section  1120  of the flexible plate shaped electrode  1114 . 
         [0187]    As illustrated in  FIGS. 35 and 36 , when the treatment apparatus  40 T is moved distally with respect to the catheter  1112  to deploy the electrode  1114  the petals  1116  move outwardly until the petal tips come into contact with the walls of the bronchial tube B. The flexible plate shaped electrode  1114  is preferably formed of a conductive material and fixed to the end of a shaft  1122 . Electric cables  1124  connect the plate shaped electrode  1114  to the energy source. 
         [0188]    The electrodes in each of the forgoing embodiments may be fabricated of any material which when compressed will return to an expanded configuration upon release of the compression forces. For example, one method of controlling the expansion of the electrodes is the use of shape memory alloy electrodes. With a shape memory alloy, the constraint of the electrodes within a catheter may not be necessary. The shape memory alloy electrodes may be formed to expand to an expanded energy delivery configuration upon heating to body temperature within the body. The expansion of the electrodes is limited by the size of the bronchial tube in which the electrode is positioned. 
         [0189]    As described above, the heat treatment apparatus may be employed in a bipolar mode in which two different expandable electrodes are connected to two different outputs of the RF generator  1018  having opposite polarities. For example, the electrodes  1016 A,  1016 B may be connected by the electrical cables  1028 ,  1030  to different terminals of the RF generator  1018 . Alternatively, when more than two electrodes  16  are employed, multiple electrodes may be connected to one terminal of the RF generator. In each of the embodiments of the heat treatment apparatus, the oppositely charged electrodes are separated by an insulating material. For example, in the embodiment of  FIG. 36 , the inner shaft  1022  and outer shaft  1024  are formed of an insulating material. Further, in the embodiments of  FIGS. 28-30  the end cap  1056  and central shaft distal tip are formed of insulating materials. 
         [0190]    In the case where the apparatus includes only one electrode  1016  as shown in  FIG. 27 , the electrode will be connected to the positive or negative terminal of the RF generator  1018  and the opposite terminal of the RF generator will be connected to the external electrode  1032 . 
         [0191]    The frequency range of RF radiation useful in the present invention is typically about 10 KHz to about 100 MHZ, preferably in the range of about 200 KHz to about 800 KHz. However, frequencies outside this range may be used at the discretion of the operating surgeon. Typically, the amount of power employed will be from about 0.01 to 100 watts and preferably in the range of about 1 to 25 watts for about 1 to 60 seconds. Alternatively, alternating current or microwave radiation typically in the frequency range of about 1,000 MHZ to about 2,000 MHZ and preferably from about 1,100 MHZ to about 1,500 MHZ may be used in place of RF radiation. In the latter case, the RF generator  1018  is replaced with a microwave generator, and the electric cables  1028 ,  1030  are replaced with waveguides. 
         [0192]    When the heat treatment apparatus with the bipolar electrodes is positioned inside the lumen of a bronchial tube, activation of the RF generator  1018  causes tissue in the lumen wall to increase in temperature. The heating may be caused by resistance heating of the electrodes themselves and/or power losses through the tissue of the bronchial wall. The particular heat pattern in the tissue will depend on the path of the electric field created by the positioning and configuration of the electrodes. 
         [0193]    In the monopolar mode, the external electrode  1034 , shown in  FIG. 26 , having a much larger surface area than the inner electrodes is placed on the outer surface of the patient&#39;s body. For example, the external electrode  1034  can be an external metal mesh or a solid plate that is placed on the skin with conductive gel. Both the internal and external electrodes are connected to the RF generator  1018  which produces an electric field at a high frequency. Because the collective surface area of the internal electrodes is much smaller than that of the outer electrode  1034 , the density of the high frequency electric field is much higher around the internal electrodes. The electric field reaches its highest density in the region near the internal electrodes. The increased density of the field around the internal electrodes produces localized heating of the tissue around the bronchial tube without causing significant heating of the body tissue between the bronchial tube and the external electrode. 
         [0194]    In use, after the operating surgeon has placed the heat treatment apparatus within the lumen of a bronchial tube to be treated, if necessary, the catheter is retracted to expose the electrodes. In the case where the lumen of the bronchial tube has collapsed or is partially collapsed, the size of the energy emitting device is designed so that expansion of the electrodes causes the lumen to expand to its normal or noncollapsed diameter due to contact of the electrodes with the inner surface of the lumen. Alternatively, in the case where the lumen has not collapsed, the device is designed so that upon expansion the electrodes are in substantial contact with the inner surface of the lumen. Indeed, only minimum expansion may be necessary in treating a noncollapsed bronchial lumen. 
         [0195]    The degree of expansion of the electrodes of the heat treatment apparatus can be monitored by means of endoscopy, fluoroscopy, or by other suitable imaging methods of the art. Generally, the heat required is induced in the tissue of the bronchial tube wall by the RF or microwave radiation emitting from the electrodes. The RF or microwave energy is applied while observing the tissue for changes via simultaneous endoscopy, or other suitable imaging methods of the art. 
         [0196]    The electrodes employed in the heat treatment apparatus are constructed of a suitable current conducting metal or alloys such as, for example, copper, steel, platinum, and the like or of a plastic material with a conductive metal insert. The electrodes can also be constructed of a shape memory alloy which is capable of assuming a predetermined, i.e., programmed, shape upon reaching a predetermined, i.e., activation, temperature. Such metals are well known in the art as described, for example, in U.S. Pat. Nos. 4,621,882 and 4,772,112 which are incorporated herein by reference. For the present invention, the shape memory metal used should have the characteristic of assuming a deflection away (i.e., expands) from the elongated rod when activated, i.e., heated in excess of the normal body temperature and preferably between 60° C. and 95° C. A preferred shape memory alloy is available as NITINOL from Raychem Corp., Menlo Park, Calif. In one embodiment, the electrodes are constructed of NITINOL in a predetermined shape and in the alloy&#39;s super elastic phase which can withstand very large deflections without plastic deformation. 
         [0197]    Substantial tissue transformation may be achieved very rapidly, depending upon the specific treatment conditions. Because the transformation can proceed at a rather rapid rate, the RF energy should be applied at low power levels. Preferably, the RF energy is applied for a length of time in the range of about 0.1 second to about 600 seconds, and preferably about 1 to about 60 seconds. Suitable RF power sources are commercially available and well known to those skilled in the art. In one embodiment the RF generator  18  employed has a single channel, delivering approximately 1 to 100 watts, preferably 1 to 25 watts and possessing continuous flow capability. The rate of tissue damage to induce fibrosis can be controlled by varying the energy delivered to the heat treatment apparatus. Regardless of the source of energy used during treatment, the lumen or the bronchial tube is maintained at a temperature of at least about 45° C., preferably between 60° C. and 95° C. 
         [0198]    When the heat treatment apparatus includes multiple energy emitting devices, not all the electrodes need to be activated at the same time. That is, different combinations of electrodes can be employed sequentially. For example, in the case of the embodiment shown in  FIG. 26 , with two electrodes  1016 A,  1016 B, the electrodes can be activated simultaneously or sequentially. 
         [0199]    In addition, when a heat treatment apparatus includes multiple energy emitting devices, the apparatus can operate in the monopolar, bipolar mode, or both modes at the same time. For instance, one of the electrodes can be designed to operate in the bipolar mode while another electrode operates in the monopolar mode. 
         [0200]    When treating a person with obstructed air passages, a preliminary diagnosis is made to identify the air passages or bronchial tube that can be treated. In treating a particular site, excessive fluid is first removed from the obstructed air passage by conventional means such as with a suction catheter. Thereafter, the heat treatment apparatus is maneuvered to the treatment site. Depending on the diameter of the lumen of the bronchial tube, the device can be positioned directly at the treatment site or it can be positioned into place with a bronchoscope. The elongated shafts  1022 ,  1024  and outer catheter  1012  are preferably made of a flexible material so that the catheter can be maneuvered through a bronchoscope. A bronchoscope is a modified catheter which includes an illuminating and visualization instrument for monitoring the treatment site and a channel for passing instruments (e.g., the treatment apparatus) into the bronchial tubes. 
         [0201]    In operation, the bronchoscope is advanced from the person&#39;s nasal or oral cavity, through the trachea, main stem bronchus, and into an obstructed air passage. The heat treatment apparatus is advanced forward through the bronchoscope to expose the tip of the heat treatment apparatus before the heat treatment apparatus is energized. Depending on the size of the treatment apparatus, the treatment apparatus can be moved to another position for further heat treatment of the air passage. This process can be repeated as many times as necessary to form a series of patency bands supporting an air passage. This procedure is applied to a sufficient number of air passages until the physician determines that he is finished. As is apparent, the procedure can be completed in one treatment or multiple treatments. After completion of the treatment, energy is discontinued and the heat treatment apparatus is removed from the patient. 
         [0202]    Temperature monitoring and impedance monitoring can be utilized in a system which provides feedback to the user in the form of sounds, lights, other displays or a mechanism which shuts down the application of energy from the heating element to the treatment site when sufficient tissue transformation is detected and to avoid burning of the treatment site. The amount of energy applied can be decreased or eliminated manually or automatically under certain conditions. For example, the temperature of the wall of the air passage, or of the heating element can be monitored and the energy being applied adjusted accordingly. The surgeon can, if desired, override the feedback control system. A microprocessor can be included and incorporated into the feedback control system to switch the power on and off, as well as to modulate the power. The microprocessor can serve as a controller to monitor the temperature and modulate the power. 
         [0203]    The invention is also directed to the demonstration or instruction of the inventive surgical techniques including, but not limited to, written instructions, actual instructions involving patients, audio-visual presentations, animal demonstrations, and the like. 
         [0204]    As described above, the apparatus  40  of the present invention may damage cells of the airway to cause fibrosis to stiffen the airway  25  in other manners besides those described above. For example,  FIG. 37  illustrates another treatment apparatus  40 U that delivers light to the walls of the airway  25 . The light delivery device  40 U includes an outer catheter or sheath  2016  surrounding a light transmitting fiber  2018 . A light directing member  2020  is positioned at a distal end of the light delivery device  2010  for directing the light to the conduit walls. 
         [0205]    The light delivery device  40 U is used to irradiate the smooth muscle surrounding the airways to induce fibrosis and/or destroy smooth muscle tone of the airway. 
         [0206]    As shown in  FIG. 38 , the light delivery device  40 U is an elongated device such as a catheter containing a fiber optic. The light delivery device  40 U is connected by a conventional optical connection to a light source  2022 . The treatment of an airway with the light delivery device  40 U involves placing a visualization system such as an endoscope or bronchoscope into the airways. The light delivery device  40 U is then inserted through or next to the bronchoscope or endoscope while visualizing the airways. The light delivery device  40 U which has been positioned with a distal end within an airway to be treated is energized so that radiant energy is emitted in a generally radially direction from a distal end of the light delivery device. The distal end of the light delivery device  40 U is moved through the airway in a uniform painting like motion to expose the entire length of an airway to be treated to the light. The light delivery device  40 U may be passed along the airway one or more times to achieve adequate treatment. The painting like motion used to exposed the entire length of an airway to the light may be performed by moving the entire light delivery device from the proximal end either manually or by motor. 
         [0207]    The light used may be coherent or incoherent light in the range of infrared, visible, or ultraviolet. The light source  2022  may be any known source, such as a UV laser source. Preferably the light is ultraviolet light having a wavelength of about 240-350 nm or visible light in the red visible range. The intensity of the light may vary depending on the application. The light intensity should be bright enough to damage the cells of the tissue to induce fibrosis and/or to destroy the smooth muscle tone or the airway. The light intensity may vary depending on the wavelength used, the application, the thickness of the smooth muscle, and other factors. 
         [0208]      FIGS. 39-42  illustrate different exemplary embodiments of the distal tip of the light delivery device for irradiating the airway walls. In  FIG. 39 , a light delivery device  40 V includes a sheath  2016  having a plurality of windows  2024  which allow the light which has been redirected by the light directing member  2020  to pass substantially radially out of the sheath. The light directing member  2020  is fitted into the distal end of the sheath  2016 . The light directing member  2020  is a parabolic diffusing mirror having a reflective surface  2026  which is substantially parabolic in cross section. The light passes from the light source along the light transmitting fiber  2018  and is reflected by the reflective surface  2026  of the light directing member  2020  through the windows  2024 . The windows  2024  are preferably a plurality of light transmitting sections spaced around the distal end of the sheath. The windows  2024  may be open bores extending through the sheath  2016 . Alternatively, the windows  2024  may be formed of a transparent material which allows the light to pass out of the sheath  2016 . 
         [0209]      FIG. 40  illustrates an alternative embodiment of a light delivery device  40 W in which the light directing member  2020  has a conical shaped reflective surface  2032 . This conical shaped reflective surface may be formed at any desired angle which directs the light transmitted by the light transmitting fiber  2018  radially out of the sheath  2016 . The use of a conical reflective surface  2032  creates a light delivery pattern in which the light rays are directed in a generally coherent radial pattern which is at a generally fixed angle with respect to a longitudinal axis of the light delivery device. In contrast, the light delivery device of  FIG. 39  with the parabolic reflective surface  2026  directs light in a diverging radial pattern which will illuminate a larger area of the airway walls. 
         [0210]      FIG. 41  illustrates a further alternative embodiment of a light delivery device  40 X in which the light directing member  2020  is a substantially conical member including concave reflective surfaces  2036 . These concave reflective surfaces  2036  direct the light which passes in a generally parallel arrangement through the light transmitting fiber  2018  out of the sheath  2016  in a converging or crossing pattern. In addition, in the embodiment of  FIG. 41 , the windows have been replaced by a transparent tip  2038  of the sheath  2016 . 
         [0211]    The light directing members  2020  having a reflective surface as illustrated in  FIGS. 39-41  may be formed in any of the known manners, such as by coating a molded member with a reflective coating, such as aluminum. 
         [0212]    As an alternative to the reflective light directing members of  FIGS. 39-41 , treatment apparatus  40 Y includes a diffusing lens  2042 , such as a Teflon lens, that may be positioned at the end of the light transmitting fiber  2018  as illustrated schematically in  FIG. 42 . The diffusing lens  2042  may direct the light from the light transmitting fiber  2018  in a generally conical pattern as shown in  FIG. 42 . Alternatively, the diffusing lens  2042  may direct the light in a more radially oriented pattern with the light rays being prevented from exiting the lens in a direction substantially parallel with the longitudinal axis of the light transmitting fiber  2018  by a reflective or blocking member. In the embodiment of  FIG. 42 , the sheath  2016  surrounding the light transmitting fiber  2018  and the diffusing lens  2042  may be eliminated entirely and the lens may be affixed directly to the end of the fiber. 
         [0213]    According to one alternative embodiment, the light delivery devices  40 U,  40 V,  40 W,  40 X,  40 Y can be used in conjunction with photo activatable substances such as those known as psoralens. These light activatable compounds, when activated, enhance the ability of visible light to destroy tissue. The psoralens may by injected intravenously. The light delivered by the light delivery devices is matched to the absorption spectrum of the chosen psora lens such that the light exposure activates the compound. When such light activatable substances are employed, a lower light intensity may be used to cause trauma to the tissue than the light intensity required to achieve destruction without the light activatable compounds. 
         [0214]      FIGS. 43-56  illustrate further embodiments of treatment apparatus that may be used with the methods of the present invention. The treatment apparatus of  FIGS. 43-53  include tissue contacting electrodes configured to be placed within the airway. These apparatus can be used for delivering radio frequency in either a monopolar or a bipolar manner or for delivering other energy to the tissue, such as conducted heat energy from resistively heated electrodes, similar to the previously described treatment apparatus. For monopolar energy delivery, one or more electrodes of the treatment apparatus are connected to a single pole of the energy source  3032  and an optional external electrode  3044  is connected to an opposite pole of the energy source. For bipolar energy delivery, multiple electrodes are connected to opposite poles of the energy source  3032  and the external electrode  3044  is omitted. The number and arrangement of the electrodes may vary depending on the pattern of energy delivery desired. The treatment apparatus of  FIGS. 54 and 55  are used to deliver radiant or heat energy to the airway. The treatment apparatus of  FIG. 54  can also deliver indirect radio frequency or microwave energy to the tissue. Finally, the treatment apparatus of  FIG. 56  is used to remove heat energy from the tissue. 
         [0215]    The treatment apparatus  40 Z of  FIG. 43A  includes a catheter  3036  for delivering a shaft  3040  having a plurality of electrodes  3038  to a treatment site. The electrodes  3038  are formed from a plurality of wires which are soldered or otherwise connected together at two connection areas  3042 . The electrodes  3038  between the connection areas  3042  are formed into a basket shape so that arch shaped portions of the wires will contact the walls of an airway. The wires may be coated with an insulating material except at the tissue contact points. Alternatively, the wires of the basket may be exposed while the connection areas  3042  and shaft  3040  are insulated. Preferably, the electrodes  3038  are formed of a resilient material which will allow the distal end of the treatment apparatus to be retracted into the catheter  3036  for delivery of the catheter to the treatment site and will allow the electrodes to return to their original basket shape upon deployment. The treatment apparatus  40 Z is preferably configured such that the electrodes  3038  have sufficient resilience to come into contact with the airway walls for treatment. 
         [0216]      FIG. 43B  illustrates a treatment apparatus  40 AA in which the distal end of the device is provided with a ball shaped member  3050  for easily inserting the device to a treatment site without causing trauma to surrounding tissue.  FIG. 43C  illustrates a treatment apparatus  40 AB having electrodes  3038  connected to the distal end of the catheter  3036  and forming a basket shape. The basket shape may be expanded radially during use to insure contact between the electrodes  3038  and the airway walls by pulling on a center pull wire  3052  which is connected to a distal end  3050  of the device and extends through a lumen of the catheter  3036 . The treatment apparatus  40 A may be delivered to a treatment site through a delivery catheter or sheath  3054  and may be drawn along the airway to treat the airway in a pattern of longitudinal or helical stripes. 
         [0217]      FIG. 44  illustrates a treatment apparatus  40 AC in which a catheter shaft  3046  is provided with a plurality of electrodes  3048  positioned on inflatable balloons  3050 . The balloons  3050  are inflated through the catheter shaft  3046  to cause the electrodes  3048  come into contact with the airway walls  3100 . The electrodes  3048  are preferably connected to the energy source  3032  by conductive wires (not shown) which extend from the electrodes through or along the balloons  3050  and through the catheter shaft  3046  to the energy source. The electrodes may be used in a bipolar mode without an external electrode. Alternatively, the treatment apparatus  40 C may be operated in a monopolar mode with an external electrode  3044 . The electrodes  3048  may be continuous circular electrodes or may be spaced around the balloons  3050 . 
         [0218]    An alternative apparatus device  40 AD of  FIG. 45  includes a catheter  3056  having one or more grooves  3060  in an exterior surface. Positioned within the grooves  3060  are electrodes  3058  for delivery of energy to the airway walls. Although the grooves  3060  have been illustrated in a longitudinal pattern, the grooves may be easily configured in any desired pattern. Preferably, the treatment apparatus  400  of  FIG. 45  includes a biasing member (not shown) for biasing the catheter  3056  against the airway wall such that the electrodes  3058  contact the tissue. The biasing member may be a spring element, an off axis pull wire, an inflatable balloon element, or other biasing member. Alternatively, the biasing function may be performed by providing a preformed curve in the catheter  3056  which causes the catheter to curve into contact with the airway wall when extended from a delivery catheter. 
         [0219]      FIG. 46  illustrates a treatment apparatus  40 AE having one or more electrodes  3068  connected to a distal end of a catheter  3066 . The electrodes  3068  are supported between the distal end of the catheter  3066  and a device tip  3070 . A connecting shaft  3072  supports the tip  3070 . Also connected between the distal end of the catheter  3066  and the tip  3070  is a spring element  3074  for biasing the electrodes  3068  against a wall of the airway. The spring element  3074  may have one end which slides in a track or groove in the catheter  3066  such that the spring can flex to a variety of different positions depending on an internal diameter of the airway to be treated. 
         [0220]      FIG. 47  illustrates an alternative treatment apparatus  40 AF in which the one or more electrodes  3078  are positioned on a body  80  secured to an end of a catheter  3076 . In the  FIG. 47  embodiment, the body  3080  is illustrated as egg shaped, however, other body shapes may also be used. The electrodes  3078  extend through holes  3082  in the body  3080  and along the body surface. A biasing member such as the spring element  3084  is preferably provided on the body  3080  for biasing the body with the electrodes against the airway walls. Leads  3085  are connected to the electrodes and extend through the catheter  3076  to the energy source  3032 . 
         [0221]      FIGS. 48 and 49  illustrate a further treatment apparatus  40 AG having one or more loop shaped electrodes  3088  connected to a catheter shaft  3086 . In the unexpanded position shown in  FIG. 48 , the loop of the electrode  3088  lies along the sides of a central core  3090 . A distal end of the loop electrode  3088  is secured to the core  3090  and to an optional tip member  3092 . The core  3090  is slidable in a lumen of the catheter  3086 . Once the treatment apparatus  40 AG has been positioned with the distal end in the airway to be treated, the electrode is expanded by pulling the core  3090  proximally with respect to the catheter  3086 , as shown in  FIG. 49 . Alternatively, the electrode  3088  or the core  3090  may be spring biased to return to the configuration of  FIG. 49  when a constraining force is removed. This constraining force may be applied by a delivery catheter or bronchoscope through which the treatment apparatus  40 AG is inserted or by a releasable catch. 
         [0222]    The treatment apparatus  40 AH of  FIG. 50  includes a plurality electrodes  3098  positioned on leaf springs  3096  which are outwardly biased. The leaf springs  3096  are connected to a shaft  3102  which is positioned within a delivery catheter  3094 . The leaf springs  3096  and electrodes  3098  are delivered through the delivery catheter  3094  to a treatment site within the airways. When the leaf springs  3096  exit the distal end of the delivery catheter  3094 , the leaf springs bend outward until the electrodes  3098  come into contact with the airway walls for application of energy to the airway walls. 
         [0223]      FIGS. 51 and 52  illustrate embodiments of treatment apparatus  40 AI,  40 AJ in which electrodes  3106  in the form of wires are positioned in one or more lumens  3108  of a catheter  3104 . Openings  3110  are formed in the side walls of the catheters  3104  to expose the electrodes  3106 . As shown in  FIG. 51 , the treatment apparatus  40 AI has multiple lumens  3108  with electrodes provided in each of the lumens. The side wall of the treatment apparatus  40 AI is cut away to expose one or more of the electrodes  3106  through a side wall opening  3110 . In  FIG. 51 , the opening  3110  exposes two electrodes positioned in adjacent lumens. The treatment apparatus  40 AI may be provided with a biasing member as discussed above to bring the electrodes  3106  of the treatment apparatus into contact with the airway wall. 
         [0224]    The treatment apparatus  40 AJ of  FIG. 52  includes a catheter  3104  which has been formed into a loop shape to allow the electrode  3106  to be exposed on opposite sides of the device which contact opposite sides of the airway. The resilience of the loop shape causes the electrodes to come into contact with the airway walls. 
         [0225]    The treatment apparatus  40 AK of  FIG. 53  is in the form of a balloon catheter. The treatment apparatus  40 AK includes electrodes  3118  positioned on an exterior surface of an inflatable balloon  3116 . The electrodes  3118  are electrically connected to the energy source  3032  by the leads  3120  extending through the balloon and through the lumen of the balloon catheter  3114 . The balloon  3116  is filled with a fluid such as saline or air to bring the electrodes into contact with the airway wall  3100 . 
         [0226]      FIG. 54  illustrates an alternative embodiment of a balloon catheter treatment apparatus  40 AM in which a fluid within the balloon  3126  is heated by internal electrodes  3128 . The electrodes  3128  are illustrated in the shape of coils surrounding the shaft of the catheter  3124 , however other electrode shapes may also be used. The electrodes  3128  may be used as resistance heaters by application of an electric current to the electrodes. Alternatively, radio frequency or microwave energy may be applied to the electrodes  3128  to heat a fluid within the balloon  3126 . The heat then passes from an exterior of the balloon  3126  to the airway wall. The radio frequency or microwave energy may also be applied indirectly to the airway wall through the fluid and the balloon. In addition, hot fluid may be transmitted to the balloon  3126  from an external heating device for conductive heating of the airway tissue. 
         [0227]      FIG. 55  illustrates a treatment apparatus  40 AN for delivering heated fluid to the airway walls to heat the airway tissue. The treatment apparatus  40 A includes a heating element  3132  provided within a fluid delivery catheter  3134 . The fluid passes over the heating element  3132  and out of openings  3136  in the end of the catheter  3134 . The openings  3136  are arranged to direct the fluid at the airway walls  3100 . The heating element  3132  may be a coiled resistance heating element or any other heating element. The heating element  3132  may be positioned anywhere along the body of the catheter  3134  or may be an external heating device separate from the catheter. 
         [0228]    The heating element  3132  may also be replaced with a friction producing heating element which heats fluid passing through the fluid delivery catheter  3134 . According to one embodiment of a friction producing heating element, a friction element rotates and contacts a stationary element for purpose of heating the fluid. 
         [0229]      FIG. 56  illustrates an alternative embodiment of a treatment apparatus  40 AP including a cryoprobe tip  3150  for transferring or removing energy in the form of heat from an airway wall  3100 . The cryoprobe tip  3150  is delivered to the treatment site by a cryoprobe shaft  3152 . Transfer of energy from the tissue structures of the airway wall can be used in the same manner as the delivery of energy with any of the devices discussed above. The particular configuration of the cryoprobe treatment apparatus  40 AP may vary as is known in the art. 
         [0230]      FIGS. 57 and 58  illustrate another embodiment of a treatment apparatus  40 AQ that may be used to treat a lung according to the present invention. The treatment apparatus  40 AQ, like the previously described treatment apparatus, damages tissue of the airway  25  so as to induce fibrosis and add thickness to the airway wall. The treatment apparatus  40 AQ also destroys the airway smooth muscle tone to increase gas exchange. With the treatment apparatus  40 AQ, a bristled brush  4000  having a plurality of bristles  4002  is introduced into the airway  25  so as to puncture the airway wall with the bristles  4002 . The bristles  4002  may be needles, pins, or other similarly shaped members. The bristles  4002  are located at the distal end of an elongated member  4004 . The bristles  4002  extend radially outward from the outer surface of the distal end of the elongated member  4004 , and are preferably flexible. The brush  4000  has at least one bristle  4002  that may be manipulated to damage the tissue of the airway  25 . 
         [0231]    As shown in  FIG. 57 , the brush  4000  is inserted through a tube-like member or cannula  4006  which has been inserted into the airway  25 . Because the outer diameter of the brush  4000  (as measured about the most distal ends or tips of the bristles  4002 ) is greater than the interior diameter of the cannula  4006 , the bristles  4002  bend against the interior surface of the cannula  4006  when the brush  4000  is located within the interior of the cannula  4006 . 
         [0232]      FIG. 58  illustrates the brush  4000  after it has been pushed through the most distal opening  4005  of the cannula  4006 . Hence, as shown in  FIG. 58 , the brush  4000  is located at least partially outside of the cannula  4006 . As also shown by  FIG. 58 , when the brush  4000  exits the outlet  4005  of the cannula  4006 , the bristles  4002  will return radially outward to their original straight configuration, rather than the bent configuration shown in  FIG. 57  where the bristles interfere with the interior surface of the cannula  4006 . Hence, the bristles  4002  extend radially outward toward the wall of the airway  25  when the distal end of the brush is forced through the opening of the cannula. As shown in  FIG. 58 , the bristles  4002  have penetrated the wall of the airway  25  to thus cause trauma to the tissue. Once the brush  4000  of the treatment apparatus  40 A extends from the outlet  4005  of the cannula  4006 , the brush  4000  may be moved along the length of the duct as illustrated by the arrow  4007  in  FIG. 58  so as to cause further trauma and damage to the airway  25 . Additionally, as also illustrated by the arrow  4009  in  FIG. 58 , the brush  4000  may be rotated while in the airway  25  so as to cause damage to the airway  25 . The brush  4000  may be moved along the select lengths of the airway  25  to damage predetermined portions of the airway, as desired. After the desire˜damage has been completed, the brush  4000  may be retracted back through the opening  4005  of the cannula  4000  such that undesired damage is not caused to other portions of the airway  25  when the brush  4000  is removed from the airway and eventually the lung. 
         [0233]    The bristles  4002  are preferably the flexible pins illustrated in  FIG. 58 , and are preferably made of a metallic material such as stainless steel. The bristles preferably have a caliber that permits them to be easily bent and resiliently return to their original position after being bent. However, the bristles  4002  may take other forms. For example, the bristles  4002  may be rigid and substantially not elastic such that they are not easily bendable. That is, the bristles may be needle-like members. In this case, the length of each needle-like member must be sufficiently small so that the brush  4000  may travel through the cannula  4006 , because the needle-like members will not bend in the cannula  4006  when contacting the interior surface of the cannula  4006 . The brush  4000  has needle-like members which may be manipulated in the airway  25  so as to cause trauma to the airway wall. 
         [0234]    The bristles  4002  preferably each have a sharp point or tip that will puncture the airway wall to cause damage and thus induce fibrosis and/or destroy smooth muscle tone. However, the tips of the bristles may be blunt such that the bristles will tear or rip the airway, rather than simply puncturing the airway wall. In this case, the tearing action will damage cells of tissue to induce a fibrotic response. Alternatively, the bristles  4002  may be razor-like members having a sharp longitudinal edge that slices the airway  25  to cause damage. 
         [0235]      FIGS. 59 and 60  illustrate another embodiment of a treatment apparatus  40 AR for use with the method of the present invention. The treatment apparatus  40 AR causes damage to the airway  25  by preferably cutting through the airway wall. The treatment apparatus  40 AR includes a cutting device  4100  having a plurality of elongated blades  4102 ,  4103 . As shown by the end view in  FIG. 60A , the elongated blades  4102 ,  4103  are circumferentially spaced at four locations along the exterior surface of an inner rod  4104 . However, additional blades may be included. For example, the blades may be circumferentially spaced at eight locations along the exterior surface of the inner rod  4104 . 
         [0236]    The inner rod or tube  4104  is located at least partially inside the interior of an outer tube or cannula  4106 . As shown by the arrow  4107  in  FIG. 60 , the inner tube  4104  is movable within the interior of the outer tube  4106  along the lengthwise direction of the outer tube  4106 . As shown in  FIGS. 59 and 60 , each of the elongated blades  4102  is pivotally connected to the inner tube  4104  by a pivot connection  4112  located at the most distal end of the inner tube  4104  so as to be rotatable about the pivot connection  4112 . Each of the elongated blades  4102  located toward the distal end of the inner rod  4104  is also pivotally connected by another pivot connection  4110  to another elongated blade  4103 . Hence, the pivot connection  4110  defines a point about which each of the blades  4102 ,  4103  rotates. The elongated blade  4103  is pivotally connected to the outer tube  4106  by a further pivot blade connection  4108  so as to be rotatable about the pivot connection  4108 . Hence, the blades  4102  and  4103  are movable in the direction shown by the arrow  4109  in  FIG. 60  when relative motion occurs between the inner tube  4104  and the outer tube  4106 , preferably when the inner tube  4104  and/or the outer tube  4106  are moved in the direction of the arrow  4107 . For example, when the inner tube  4104  and the outer tube  4106  are moved from the positions illustrated in  FIG. 59  to the positions illustrated in  FIG. 60 , each of the elongated blades  4102  and  4103  will pivot about the pivot connections  4108 ,  4110 ,  4112  such that the elongated blades  4102 ,  4103  move toward the wall of the airway  25  and cut through tissue of the airway to induce fibrosis. The more the most distal end of the inner tube  4104  having the pivot connection  4112  and the most distal end of the outer tube  4106  having the pivot connection  4108  are moved toward each other, the more the blades  4102 ,  4103  will rotate about the pivot connections  4112 ,  4110 ,  4108 . In this manner, the elongated blades  4102 ,  4103  may be caused to cut through the tissue of the airway  25  so as to cause trauma. Preferably, the elongated blades  4102 ,  4103  will damage tissue  27  such that scar tissue develops to thicken the wall of the airway and thus strengthen the airway. As shown in  FIG. 60 , the elongated blades  4102 ,  4103  have cut or sliced through the tissue of the airway. 
         [0237]    The elongated blades  4102 ,  4103  may be repeatedly collapsed and expanded as shown in  FIGS. 59 and 60  so as to cause multiple cuts to the airway tissue, as desired. Additionally, the elongated blades  4102 ,  4103  may be moved in the longitudinal direction of the airway wall while the blades are in the expanded position shown in  FIG. 60  so as to further slice the airway tissue. Likewise, the cutting apparatus  4100  may be rotated in the airway  25  as shown by the arrow  4105  in  FIG. 60  so as to cut and/or tear the tissue of the airway  25 . 
         [0238]    The elongated blades  4102 ,  4103  are preferably thin razor-like elongated members of stainless steel that easily slice through the airway tissue. However, the elongated blades  4102 ,  4103 , may take other configurations. For example, the elongated blades  4102 ,  4103  may be rods having a serrated surface or surfaces that cut or tear through the airway tissue. Additionally, the elongated blades  4102 ,  4103  may each include a plurality of pins that function to penetrate or puncture the airway tissue to destroy smooth muscle tone and/or induce fibrosis to strengthen the airway wall and thus improve gas exchange efficiency. 
         [0239]      FIGS. 61-62  illustrate a further embodiment of a treatment apparatus  40 AS for use with the method of the present invention. The treatment apparatus  40 AS includes a slicing device  4200  that slices through the airway tissue to destroy smooth muscle tone and/or damage lung tissue and induce fibrosis to strengthen the airway wall. The slicing device  4200  includes a plurality of elongated slicing members  4202  that each include a razor edge  4208  located at the most distal end of the slicing members. The slicing members  4202  are preferably elongated metallic members that protrude from the an outlet  4201  of an inner tube  4204 . The slicing members  4202  are movable in the inner tube  4202  along the lengthwise direction of the inner tube  4204  as shown by the arrows  4207  illustrated in  FIG. 62 . The inner tube  4204 , similar to the previously described embodiments, is located within an outer tube or cannula  4206 . The slicing members  4202  may be forced out of an opening  4203  of the outer tube  4206  at the most distal end of the outer tube such that they project outwardly from the end of the outer tube  4206 .  FIG. 61  illustrates the slicing members  4202  located completely inside of the outer tube  4206 , while  FIG. 62  illustrates the slicing members  4202  after they have been moved out of the opening  4203  of the outer tube  4206 . The slicing members  4202  may be manually forced through the opening  4203  or automatically caused to move through the opening  4203  by a controller (not illustrated). 
         [0240]    As illustrated in  FIGS. 61 and 62 , when the slicing members  4202  are moved out of the opening  4203 , they bend or curve away from the longitudinal axis of the outer tube  4206  such that the members slice through the airway tissue of the airway  25 . Hence, the slicing members  4202  are preferably biased to bend away from the longitudinal axis of the outer tube  4206 . That is, each of the slicing members acts like a spring and moves toward the airway wall after exiting the outlet  4203 . 
         [0241]    The slicing members  4202  may be attached to the inner tube  4204  such that the slicing members  4202  move with the inner tube  4204  when the inner tube is moved relative to the outer tube  4206 . Additionally, the slicing members  402  may not be attached to the inner tube  4204  such that they are movable relative to the inner tube  4204 , as well as the outer tube  4206 . As shown by the arrow  4209  in  FIG. 61 , the slicing members  4202  can be rotated relative to the airway  25  during the treatment process so as to slice, cut, or tear through the airway wall to cause further trauma. 
         [0242]    Although the embodiment shown in  FIGS. 61-62  includes only four slicing members  4202 , other numbers of slicing members are contemplated. For example, the treatment apparatus  4 AS can slice the airway tissue with 8, 16, 32, 56, or other numbers of slicing members  4202  that are movable relative the airway  25  so as to cause damage to the airway tissue of the lung. 
         [0243]    The slicing members  4202  can be moved to repetitively slice through the tissue of the airway  25  so as to define a plurality of sliced areas  4210 . In general, the greater the number of sliced areas  4210  made with the treatment apparatus  40 AS, the greater the damage of smooth muscle tone and the greater the fibrotic response, which will thicken the airway wall and strengthen the airway wall to thus increase gas exchange. 
         [0244]    The slicing members  4202  are preferably thin and elongated members having a razor edge  4208 . However, the slicing members  4202  can be other configurations. For example, each of the slicing members  4202  may include a pin point rather than a razor edge. Additionally, each of the slicing members  4202  may include serrations or a razor edge along the elongated edges or sides of the slicing members  4202 , which may extend the entire length of the slicing member or only along predetermined portions of the length. 
         [0245]      FIGS. 63-65  illustrate further embodiments of treatment apparatus  40 AT for use with the present invention. As shown in  FIG. 63 , the treatment apparatus  40 AT includes a balloon  4312  having a plurality of pins  4308  attached to the outer surface of the balloon. The balloon  4312  is similar to the previously described balloons and may be fabricated from like materials. The balloon  4312  is partially located within an inner tube  4304 , as well as a containment sheath  4309 . The balloon  4312  extends from the outlet end of the inner tube  4304 . As shown in  FIG. 64 , the inner tube  4304  is connected to a fluid supply  4314 , which can supply a pressurized gas or fluid to the interior of the tube  4304  and hence the interior of the balloon  4312  to cause the balloon to expand as shown in  FIG. 64 . 
         [0246]    The sheath  4309  that surrounds or encases the balloon  4312  includes a plurality of openings  4302  that extend through the cylindrical wall of the sheath  4309 . Hence, the openings  4302  communicate the exterior of the sheath  4309  with the interior of the sheath. The balloon  4312  is attached to the sheath  4309  at the most distal end  4310  of the sheath. The openings  4302  in the sheath  4309  are located at locations on the exterior surface of the sheath  4309  such that when the balloon  4312  is expanded the pins  4308  will travel through the openings  4302  and protrude from the exterior surface of the sheath  4309 . That is, the openings  4302  are spaced along the length and the circumference of the sheath  4309  the same distance that the pins  4308  are spaced along the length and circumference of the balloon  4312 . Hence, when the balloon  4312  is expanded upon application of pressure by the fluid supply  4314 , the pins will move radially toward the airway and extend through the openings  4302 . When the balloon  4312  has been fully expanded as shown in  FIG. 64 , the pins  4308  will protrude through the openings  4302  and will puncture the tissue of the airway  25  so as to destroy smooth muscle tone and/or induce fibrosis and strengthen the airway. 
         [0247]    The sheath  4309  is preferably formed of a rigid material, such as hard plastic, so that the location of the openings  4302  relative to the location of the pins  4308  on the balloon  4312  remains relatively constant during the treatment process. The sheath  4309  is preferably attached to the outer tube  4306  such that the sheath  4309  will move when the outer tube  4306  is moved: Hence, after the balloon has been expanded to cause pins  4308  to extend through the openings  4302  and puncture the airway tissue, the sheath  4309 , the outer tube  4306 , the balloon, and the pins  4308  may be moved in the longitudinal direction of the airway  25  so as to further tear or slice through the airway tissue. Likewise, as shown by the arrow  4307  shown in  FIG. 64 , the sheath  4309  may be rotated so as to rotate the pins  4308  to cause further damage to the tissue of the airway. 
         [0248]    As shown in  FIGS. 63 and 64 , the pins  4308  are located on diametrically opposite sides of the balloon  4312 , as are the openings  4302  of the sheath  4309 . However, the balloon  4312  may include further rows and columns of pins  4308  and the sheath may include further rows and columns of openings  4302 , as illustrated by the embodiment of the treatment apparatus  40 AT illustrated in  FIG. 65 . As shown in  FIG. 65 , the balloon  4312  includes eight rows of pins  4308  equally spaced along the length and circumference of the balloon  4312 . Hence, the sheath  4309  also includes correspondingly located openings  4302  that the pins  4308  may protrude through when the balloon  4312  is expanded. Other numbers of pins  4308  and openings  4302  are also contemplated. 
         [0249]    The balloons of the embodiments illustrated in  FIGS. 63-65  can be repeatedly expanded and contracted so as to cause multiple punctures to the airway tissue to destroy the airway smooth muscle tone and induce fibrosis and hence stiffen the wall of the airway. Additionally, the pins  4308  can be other configurations. For example, a plurality of razors, knives, or blunt members can be attached to the balloon such that the airway tissue is sliced, cut, or torn when the balloon is expanded. 
         [0250]      FIG. 66  illustrates another embodiment of a treatment apparatus  40 AU that may be used according to the present invention. The treatment apparatus  40 AU includes a balloon  4412 , which is illustrated in its expanded state in  FIG. 66 . The balloon  4412  includes a plurality of openings  4402  that communicate the exterior of the balloon with the interior of the balloon. The openings  4402  are a plurality of small holes that extend through the wall of the balloon  4412 . The balloon  4412  is attached to the end of a tube or cannula  4406 . The interior of the balloon  4412  may be filled with a liquid or gas from the fluid supply  4408 . Hence, the fluid supply  4408  is in communication with the interior of the balloon  4412  through the tube  4406 . The balloon may be expanded as shown in  FIG. 66  by pressurizing the interior of the balloon  4412  with a liquid or gas from the supply  4408 . The liquid or gas supplied from the supply  4408  will exit the balloon  4412  through the openings  4402  located in the balloon. The expanded balloon  4412  contacts with the airway wall. Hence, when the fluid exits the balloon  4412  through the openings  4402 , it will contact the tissue of the airway  25 . The fluid that exits the balloon  4412  may be a heated liquid or gas, similar to the above-described embodiments that destroy cells of the airway tissue by the application of heat. The fluid is preferably a biocompatible liquid, such as liquid saline or air. Additionally, the fluid delivered by the supply  4408  may be cold liquid or gas that destroys the airway tissue by removing heat from the airway tissue when it passes through the openings  4402  of the balloon  4412 . In a preferred embodiment of the treatment apparatus  40 AU, the liquid or gas supplied by the supply  4408  is cooled to a temperature that destroys airway smooth muscle tone and/or damage airway tissue to induce a fibrotic response to strengthen the airway  25 . The liquid or gas delivered by the treatment apparatus  40 AU can also destroy tissue cells by chemically reacting with the tissue. For example, the treatment apparatus  40 AU can deliver an acid to the airway tissue to cause trauma to the tissue. 
         [0251]    Although the expanded balloon  4412  illustrated in  FIG. 66  contacts the wall of the airway  25 , the balloon  4412  can be smaller than the airway  25  such that it does not contact the airway wall when expanded. 
         [0252]      FIGS. 67 and 68  illustrate another embodiment of a treatment apparatus  40 A that can be used to perform the present method of the invention. The treatment apparatus  40 AV, like the apparatus  40 AU illustrated in  FIG. 66 , includes a balloon  4512 . The balloon  4512  is illustrated in its collapsed condition in  FIG. 67 , and is illustrated in its expanded condition in  FIG. 68 . As shown in  FIGS. 67 and 68 , the balloon  4512  includes a plurality of tubes  4504  attached to the exterior surface of the balloon  4512 . The interior of the balloon  4512  is not in communication with the interior of the tubes  4504 . The plurality of tubes  4504  are preferably circumferentially spaced about the exterior cylindrical surface of the balloon  4512 . Each of the tubes  4504  extends along the longitudinal length of the balloon  4512  and through the interior of a tube or cannula  4508 . Like the embodiment illustrated in  FIG. 66 , the balloon  4512  may be inflated by a fluid supply  4514  which supplies a gas or liquid to the interior of the balloon  4512  to cause it to expand to the position illustrated in  FIG. 68 . However, unlike the embodiment illustrated in  FIG. 66 , the expansion of the balloon  4512  does not cause a liquid or gas to be delivered to the wall of the airway  25 . Rather, a separate fluid supply  4510  delivers a liquid or gas to the interior of each of the tubes  4504 . 
         [0253]    The liquid or gas delivered by the fluid supply  4510  travels through the interior of the elongated tubes  4504  and out of a plurality of openings  4502  spaced along the length of each of the tubes  4504 . The openings  4502  are equidistantly spaced along the length of the tube  4504 . Hence, after the balloon is expanded by pressure from the supply  4514 , the supply  4510  may supply a liquid or gas to the interior of the tubes  4504  and out of the openings  4502  such that the liquid or gas from the supply  4510  contacts the airway tissue. As with the embodiment described above in reference to  FIG. 66 , the liquid or gas supplied from the supply  4510  will damage the airway tissue. The fluid or gas delivered through the holes  4502  damages tissue  27  to induce fibrosis and thicken the wall of the airway  25  so as to strengthen the airway wall and increase the gas exchange efficiency of the lung. The fluid or gas can also destroy the smooth muscle tone to increase gas exchange. 
         [0254]      FIG. 69  illustrates an additional embodiment of a treatment apparatus  40 AW for use with the methods of the present invention. The treatment apparatus  40 AW includes a tube or cannula  4604  having a plurality of holes  4602  located at a most distal end of the tube  4604 . The plurality of holes  4602  form a plurality of columns and rows about the circumference of the tube  4604 , as illustrated in  FIG. 69 . The holes  4602  deliver a fluid, such as that described above in reference to  FIGS. 66-68  to the tissue of the airway  25  to damage cells and induce fibrosis. As shown in  FIG. 69 , a gas supply  4610  and/or a liquid supply  4612  may deliver a fluid to the interior of the tube  4604 , through the holes  4602 , and to the tissue of the airway  25 . In this manner, a gas and/or a fluid will destroy smooth muscle tone and/or damage tissue to induce fibrosis and increase the gas exchange efficiency of the lung. 
         [0255]      FIG. 70  illustrates a further embodiment of a treatment apparatus  40 AX for use with the methods according to the present invention. The treatment apparatus  40 AX, like the embodiments illustrated in  FIGS. 66-69 , delivers a liquid or a gas to the airway  25  so as to damage of the airway tissue. In the embodiment illustrated in  FIG. 70 , an inner tube  4702  is located within an outer tube  4704 . The inner tube  4702  may be connected to a gas supply or a liquid supply  4710 . Likewise, the outer tube  4704  may be connected to a gas supply or liquid supply  4712 . The fluid delivered to the interior of the inner tube  4702  from the supply  4710  exits the outlet  4708  at the distal end of the inner tube  4702 . The fluid delivered from the supply  4712  exits the outlet  4706  at the most distal end of the outer tube  4704 . Because there are two separate tubes  4702 ,  4704 , and two separate supplies  4710 ,  4712 , two separate liquids, two separate gases, or a combination of liquids and gases may be delivered to the airway tissue to cause trauma to destroy smooth muscle tone and/or cause fibrosis and strengthen the airway  25 . For example, two liquids or gases may be combined at the outlets  4706 ,  4708  to cause a chemical reaction that damages the cells of the airway tissue to induce fibrosis. 
         [0256]      FIGS. 71 and 72  illustrate a bronchoscope, such as described earlier, that may be used with each of the above-described treatment apparatus  40 . The bronchoscope  5000  has a treatment apparatus  40  slidably positioned within a lumen of the bronchoscope. The bronchoscope also includes an image-transmitting fiber  5008  and illuminating fiber  5020 . Any conventional bronchoscope with an appropriately sized and directed working lumen may be employed. The image transmitting fiber collects light from the distal end of the treating apparatus and directs the light to a viewing apparatus (not shown) for displaying an image of the air passage. The bronchoscope may have a panning system which enables the tip to be moved in different directions. In treating a particular site, excessive fluid is first removed from the obstructed air passage by conventional means such as with suction. Thereafter, the bronchoscope as illustrated in  FIGS. 71 and 72  is advanced from the person&#39;s nasal or oral cavity, and through the trachea, main stem bronchus, and into an air passage. The treatment apparatus  40  is advanced forward from the bronchoscope such that the treatment apparatus may be used to destroy airway smooth muscle tone and/or cause damage to airway tissue to induce fibrosis and strengthen an airway of the lung. This procedure is applied to a sufficient number of obstructed air passages until the physician determines that the treatment is finished. As is apparent, the procedure can be completed in one treatment or multiple treatments. The bronchoscope and the treatment apparatus  40  are then removed from the patient. 
         [0257]    The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.