Patent Publication Number: US-2023149019-A1

Title: Filling liquid, balloon delivery device, medical ultrasonic device, medical system, tubular organ blocking technique, and tubular organ blocking release technique

Description:
TECHNICAL FIELD 
     The present disclosure relates to a filling liquid, a balloon delivery device, a medical ultrasonic device, a medical system, a method for occluding a tubular organ, and a method for terminating a tubular organ occlusion. 
     BACKGROUND ART 
     As a therapeutic method of congenital diaphragmatic hernia, tracheal occlusion, or occlusion of the fetal trachea with a balloon for a certain period of time has been proposed. 
     Congenital diaphragmatic hernia is an illness caused by a hole formed in the fetal diaphragm during the growth process of the fetus in the uterus, which allows intraperitoneal organs such as small intestine, large intestine, and stomach to migrate through the hole in the diaphragm to the thoracic cavity, resulting in an obstruction of growth of the fetal lungs. In an example of tracheal occlusion, a balloon is placed in the fetal trachea, the balloon is then inflated by liquid such as physiological saline solution injected into the balloon, and the balloon thus inflated occludes the fetal trachea. When the fetal trachea is kept occluded for a certain period of time, the pressure of the lung fluid stimulates the growth of the fetal lungs during the period and the intraperitoneal organs that entered the thoracic cavity are pushed back to the original positions in the peritoneal cavity. After that, the tracheal occlusion is terminated by deflating the balloon, in preparation for pulmonary respiration after birth. 
     A known method of terminating balloon tracheal occlusion is inserting an endoscope into the uterus and breaking the balloon with a guidewire or the like. As this technique involves endoscopic surgery, this technique is invasive to the human body and hence burdensome on the patient. Further, as endoscopic surgery needs to be performed by a medical specialist or the like, it is sometimes difficult to set up a system for that. 
     To address this, a technique using an ultrasonic wave has been proposed as a minimally invasive and easy method of terminating balloon tracheal occlusion. For example, an ultrasonic medical system recited in Patent Literature 1 includes a probe with an ultrasonic transducer and a transmitter that controls the probe in such a way as to form an ultrasonic transmission beam. The transmitter controls the probe in such a way as to form the transmission beam directed to the balloon placed in the tubular trachea. The probe transmits an ultrasonic wave along the transmission beam and causes the liquid filler that fills the balloon to evaporate due to the ultrasonic waves. This raises the pressure inside the balloon. 
     The balloon recited in Patent Literature 1 includes a backflow check valve that curtails the filler injected in the balloon from flowing out of the balloon. The backflow check valve stops curtailing the filler from flowing out when the pressure in the balloon rises. Because of this, when the pressure in the balloon rises due to the ultrasonic wave, the filler is discharged from the balloon through the backflow check valve. This deflates the balloon and hence terminates the balloon tracheal occlusion. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Unexamined Japanese Patent Application Kokai Publication No. 2013-202263. 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the conventional ultrasonic medical system, the backflow check valve may fail to stop curtailing the filler from flowing out, resulting in a failure to terminate the balloon tracheal occlusion. 
     The present disclosure is made in view of the above-described circumstances and has an objective of providing a method for occluding tubular organ and a method for terminating tubular organ occlusion that can terminate a balloon occlusion of a tubular organ such as trachea in a minimally invasive, easy, and assured way as well as a filling liquid, a balloon delivery device, a medical ultrasonic device, and a medical system for these methods. 
     Solution to Problem 
     To achieve the above-described objective, a filling liquid for filling a balloon for a method for occluding a tubular organ, according to a first aspect of the present disclosure, includes: 
     a microcapsule in which a balloon-dissolving substance that dissolves the balloon is encapsulated, wherein the microcapsule is destroyable by an ultrasonic beam; and 
     a liquid that is harmless in the tubular organ and does not dissolve the balloon. 
     A balloon delivery device according to a second aspect of the present disclosure includes: 
     a catheter to which a balloon is attachable at a front end of the catheter; and 
     injection means for injecting the filling liquid according to the first aspect of the present disclosure to a tubular tissue through the catheter. 
     A medical ultrasonic device according to a third aspect of the present disclosure includes: 
     a probe including an ultrasonic transducer; and 
     an ultrasonic wave control unit that controls the ultrasonic transducer to cause the probe to emit an ultrasonic beam that destroys the microcapsule to the balloon filled with the filling liquid according to the first aspect of the present disclosure and occluding a tubular organ. 
     A medical system according to a fourth aspect of the present disclosure includes: 
     the balloon delivery device according to the second aspect of the present disclosure; and 
     the medical ultrasonic device according to the third aspect of the present disclosure. 
     A method for occluding a tubular organ according to a fifth aspect of the present disclosure includes: 
     a step of preparing a catheter with a balloon attached to a front end of the catheter; 
     a step of delivering the balloon into a certain tubular organ by means of the catheter; 
     a step of filling the balloon with the filling liquid according to the first aspect of the present disclosure by means of the catheter, inflating the balloon, and occluding the tubular organ with the inflated balloon; and 
     a step of detaching the catheter from the balloon. 
     A method for terminating tubular organ occlusion according to a sixth aspect of the present disclosure includes 
     a step of applying the ultrasonic beam to a balloon that is filled with the filling liquid according to the first aspect of the present disclosure and occludes a tubular organ and of breaking the balloon as a result. 
     Advantageous Effects of Invention 
     According to the present disclosure, a balloon is filled with a filling liquid containing microcapsules, a balloon-dissolving substance that dissolves the balloon is encapsulated in the microcapsules, and an ultrasonic wave control unit causes a probe to emit an ultrasonic beam that destroys the microcapsules in the filling liquid in the balloon when applied to the balloon occluding the tubular organ. This makes it possible to destroy the microcapsules in the filling liquid in the balloon by simply applying the ultrasonic beam from the probe to the balloon occluding the tubular organ and to dissolve and break the balloon with the balloon-dissolving substance let out of the destroyed microcapsules. Therefore, it is possible to provide a medical system and a medical ultrasonic device that can terminate a balloon occlusion of a tubular organ in a minimally invasive, easy, and assured way. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view illustrating a configuration of a medical system according to an embodiment of the present disclosure; 
         FIG.  2    is a diagram illustrating a functional configuration of an endoscope control unit according to an embodiment; 
         FIG.  3    is a diagram illustrating a functional configuration of an ultrasonic wave control unit according to an embodiment; 
         FIG.  4    is an enlarged view of the vicinity of the thoracic cavity of a fetus affected by congenital diaphragmatic hernia; 
         FIG.  5    is a view illustrating a balloon placed in the fetal trachea by using endoscopic device; 
         FIG.  6    is a view illustrating a trachea occluded by the balloon inflated by filling liquid that fills the balloon; 
         FIG.  7    is a view illustrating the balloon detached from the endoscopic device, the balloon occluding the trachea; 
         FIG.  8    is an enlarged view of the vicinity of the fetal thoracic cavity, intraperitoneal organs pushed back out of the thoracic cavity due to the tracheal occlusion; 
         FIG.  9    is a view illustrating a first ultrasonic beam applied to the balloon; 
         FIG.  10 A  is an enlarged view illustrating the balloon and the fetal trachea during the termination of the balloon tracheal occlusion at the time of starting the application of the first ultrasonic beam; 
         FIG.  10 B  is an enlarged view illustrating the balloon and the fetal trachea during the termination of the balloon tracheal occlusion, microcapsules broken and limonene let out to the filling liquid; 
         FIG.  10 C  is an enlarged view illustrating the balloon and the fetal trachea during the termination of the balloon tracheal occlusion, the balloon broken by the effect of limonene and filling liquid let out of the balloon; and 
         FIG.  10 D  is an enlarged view illustrating the balloon and the fetal trachea during the termination of the balloon tracheal occlusion, the balloon deflated and the tracheal occlusion terminated. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present disclosure will be described below with reference to the drawings. Like elements will be denoted by like reference signs throughout the drawings. 
     A medical system  1  according to an embodiment of the present disclosure is a system for occluding a tubular organ of a living body with a balloon  170  and for terminating the occlusion, the configuration of which is illustrated in  FIG.  1   . The medical system  1  includes an endoscopic device  100  and an ultrasonic device  200 . Note that the proportions of the parts in  FIG.  1    are altered as appropriate for easier understanding. 
     (Configuration of the endoscopic device  100 ) 
     The endoscopic device  100  is a device for occluding a tubular organ of a living body with a balloon  170 . The endoscopic device  100  includes a sheath  110 , an endoscope  120 , an endoscope control unit  130 , a first syringe  150 , a first catheter  155 , a second syringe  160 , and a second catheter  165 . 
     The sheath  110  is a member used for allowing easy insertion of the insertion part  121  of the endoscope  120 , the first catheter  155 , and the second catheter  165  to the body. The sheath  110  includes a sheath body  111  and a connecter  112 . 
     The sheath body  111  is a long tubular part in which a through inner hole is defined in the longitudinal direction, into which the insertion part  121  of the endoscope  120 , the first catheter  155 , and the second catheter  165  can be inserted. The sheath body  111  is made of rigid material such as metal or hard resin. The rear part  111   a  of the sheath body  111  is approximately linearly formed. In contrast, the front part  111   b  of the sheath body  111  is curved gently, approximately in a circular arc, in order to ease insertion into a living body. Note that the sheath body  111  may have individual through inner holes respectively having inside diameters large enough to insert the insertion part  121  of the endoscope  120 , the first catheter  155 , and the second catheter  165 . 
     The connecter  112  is a part coupled to the rear end of the sheath body  111  to detachably connect the endoscope  120  with the sheath  110 . The connecter  112  has an insertion hole defined therein that communicates with the through inner hole of the sheath body  111 . The connecter  112  connects the operation part  122  of the endoscope  120  with the sheath body  111  by fitting or screwing, such that the insertion part  121  of the endoscope  120  is inserted into the sheath body  111  through the insertion hole. The connecter  112  further includes an insertion port part  113  having an insertion hole through which the first catheter  155  can be inserted and an insertion port part  114  having an insertion hole through which the second catheter  165  can be inserted. The first catheter  155  and the second catheter  165  are inserted to the through inner hole of the sheath body  111  respectively through the insertion port parts  113  and  114 . 
     The endoscope  120  is a device for making observation inside a living body. The endoscope  120  includes an insertion part  121 , an operation part  122 , and a wire  123 . 
     The insertion part  121  is an approximately cylindrical part to be inserted into a living body. The insertion part  121  is inserted into a living body, for example, with the sheath  110  attached to the endoscope  120 . The insertion part  121  is flexible and, when the sheath  110  is attached to the endoscope  120 , the insertion part  121  can be inserted into the sheath body  111  along the shape of the sheath body  111 . Further, the insertion part  121  has a length approximately equal to that of the sheath body  111  and, when the sheath  110  is attached to the endoscope  120 , the front end of the insertion part  121  does not protrude from the front end of the sheath body  111  but is slightly retreated in the sheath body  111 . Further, an imaging unit  125  for taking images inside the living body is provided at the front part of the insertion part  121 . 
     The imaging unit  125  includes, for example, a camera that includes an objective lens that condenses light from the subject, a charge-coupled device (CCD) image sensor, a complementary metal oxide semiconductor (CMOS) image sensor, and the like, and a lighting device that includes a light emitting diode (LED) and the like. 
     The operation part  122  is a part connected to the rear end of the insertion part  121  and is held by a user to operate the endoscope  120 . The operation part  122  includes a switch, a knob, and the like (not illustrated) for operating various functions of the endoscope  120 . Herein, the user is typically a doctor. 
     Note that the insertion part  121  may include in the insertion part  121  a cable wire and the like for changing the direction of the imaging unit  125  in such a way as to enable the user to direct the imaging unit  125  provided at the front part of the insertion part  121  in a desired direction to change the scope of images to be taken, by adjusting the length of the cable wire by operating a nob or the like provided on the operation part  122 . 
     The wire  123  extends through the insertion part  121  and electrically connects the imaging unit  125  with the endoscope control unit  130 . The imaging unit  125  and the endoscope control unit  130  transmit and receive various signals to and from each other through the wire  123 . 
     The endoscope control unit  130  is a unit for controlling the endoscope  120 . The endoscope control unit  130 , the functional configuration of which is illustrated in  FIG.  2   , includes an input device  131 , a controller  132 , an imaging controller  133 , a display image generator  134 , and a display  135 . 
     The input device  131  is operated by the user to input an instruction to start or end operation of the imaging unit  125  and the like as well as to input various setting values and the like. The input device  131  includes, for example, a button, a switch, and the like, physically. Note that the input device  131  together with the display  135  may form a touch panel. 
     The controller  132  controls the imaging controller  133 , the display image generator  134 , and the like in accordance with operations on the input device  131 , signals from various sensors (not illustrated), and the like. 
     The imaging controller  133  controls the imaging unit  125  under the control of the controller  132 . For example, when the imaging controller  133  acquires an instruction from the controller  132  in response to an operation on the input device  131 , the imaging controller  133  starts or ends an operation of the imaging unit  125  in accordance with the acquired instruction. Further, for example, the imaging controller  133  controls the operation of the imaging unit  125  in accordance with setting values and the like, the setting value designated by means of the controller  132  on the basis of an operation on the input device  131 . The operation of the imaging unit  125  includes, for example, taking an image with the camera, emitting light from the lighting device, and the like. 
     Under the control of the controller  132 , the display image generator  134  generates display data by acquiring image data indicating an image taken by the camera of the imaging unit  125  from the imaging unit  125  and converting the image data into display data for displaying the image on the display  135 . Such conversion processing includes, for example, conversion processing of the image data acquired from the camera of the imaging unit  125  into pixel data indicating the pixel values for the display  135 , noise removal processing, and the like. 
     The controller  132 , the imaging controller  133 , and the display image generator  134  physically include, for example, one or more processors, random access memory (RAM), read only memory (ROM), flash memory, dedicated electric circuits, and the like, which may be combined as appropriate. 
     The display  135  acquires display data from the display image generator  134  and displays the image represented by the display data. The display  135  may physically include, for example, a liquid crystal panel, a liquid crystal drive circuit, a back panel, and the like. 
     The first syringe  150  is an instrument used as injection means for injecting flush liquid  151 . The first syringe  150  is attached to the rear end of the first catheter  155  with the cylinder of the first syringe  150  filled with the flush liquid  151 . The flush liquid  151  may be, for example, physiological saline solution. When the endoscope  120  is inserted into the body, the vision of the endoscope  120  may be affected by turbidity of body liquid (amniotic fluid and the like) and the like. In such a case, the user manually operates the plunger of the first syringe  150  to inject the transparent flush liquid  151 , causes the flush liquid  151  to spout from the front end of the first catheter  155 , and thereby obtains appropriate vision of the endoscope  120 . 
     The first catheter  155  is a tubular member to be inserted into the living body in order to inject flush liquid  151  into the living body. The first catheter  155  is installed by insertion from the insertion port part  113  provided for the connecter  112  through the through inner hole defined through the sheath body  111  in the longitudinal direction, and is inserted to the living body with the sheath  110 . The flush liquid  151  filling the first syringe  150  attached to the rear end of the first catheter  155  goes through the first catheter  155  and spouts from the spout opening  156  provided at the front end of the first catheter  155 . 
     The second syringe  160  is an instrument used as injection means for injecting filling liquid  161 . The second syringe  160  is attached to the rear end of the second catheter  165  with the cylinder of the second syringe  160  filled with the filling liquid  161 . The user manually operates the plunger of the second syringe  160  to inject the filling liquid  161  to the balloon  170  attached to the front end of the second catheter  165  and thereby inflates the balloon  170 . 
     The filling liquid  161  is a liquid with which to fill the balloon  170  in order to inflate the balloon  170  in a tubular organ to occlude the tubular organ. The filling liquid  161  includes microcapsules  162  in which a material that dissolves the balloon  170  is encapsulated. The filling liquid  161  may be, for example, physiological saline solution mixed with a large number of limonene-encapsulating microcapsules  162 . Herein, a microcapsule means a fine particle in which a substance, for example, a liquid is encapsulated within a thin membrane and includes, for example, a macromolecular micelle, a liposome, an emulsion, and the like. Microcapsules  162  having a particle diameter of about 1 to 100 μm are suitable for the use but the particle diameter of the microcapsules  162  is not limited to this range. Note that it is desirable that the filling liquid  161  containing the microcapsules  162  have such a viscosity and a density as to allow the filling liquid  161  to be easily injected to the balloon  170  through the second catheter  165 . 
     For example, when liposomes are used as microcapsules  162 , limonene-encapsulating liposomes can be easily produced by the Bangham method or the like. More specifically, phospholipid, which is a component of liposome layers, is dissolved in organic solvent (for example, mixed solvent of methanol and chloroform) and the organic solvent is removed by evaporation using an evaporator, thereby forming a thin membrane. Next, the limonene to be encapsulated and physiological saline solution are added to swell the thin membrane and, further, ultrasonic processing is applied to make the particles smaller and uniform, and thus limonene-encapsulating liposomes (microcapsules  162 ) are produced. 
     The second catheter  165  is a tubular member used for injecting the filling liquid  161  into the balloon  170 . The second catheter  165  with the balloon  170  attached to the front end thereof is provided from the insertion port part  114  provided for the connecter  112  and through the through inner hole defined through the sheath body  111  in the longitudinal direction, and is inserted to the living body with the sheath  110 . The filling liquid  161  filling the second syringe  160  attached to the rear end of the second catheter  165  is injected through the second catheter  165  to the balloon  170  attached to the front end of the second catheter  165 . 
     The balloon  170  is a member in the form of a bag for occluding a tubular organ and made mainly of, for example, latex. The balloon  170  is detachably attached to the front end of the second catheter  165 . More specifically, the balloon  170  includes a backflow check valve (not illustrated), which allows the filling liquid  161  to go inside and prevents the filling liquid  161  injected inside from going outside. The balloon  170  is attached to the second catheter  165  by sticking the needle (not illustrated) provided at the front end of the second catheter  165  into the backflow check valve. 
     (Configuration of the ultrasonic device  200 ) 
     The ultrasonic device  200  is a device for terminating the occlusion of a tubular organ by the balloon  170  by using ultrasonic waves. The ultrasonic device  200  includes a probe  210 , which includes a first probe  211  and a second probe  212 , a control unit  220 , which includes a first ultrasonic wave control unit  221  and a second ultrasonic wave control unit  222 , a wire  231  electrically connecting the first probe  211  with the first ultrasonic wave control unit  221 , and a wire  232  electrically connecting the second probe  212  with the second ultrasonic wave control unit  222 . 
     The first probe  211  is an appliance that transmits, through the front part thereof which contacts the living body, a first ultrasonic beam  251   a  that breaks the microcapsules  162  in the balloon  170 . The first probe  211  includes a plurality of first ultrasonic transducers  250   a  as illustrated in FIG.  1 . 
     The first probe  211  is an annular member with a round through hole defined approximately in the center thereof. The front part of the first probe  211  has a sloped surface formed conically and concavely toward the round through hole. The plurality of first ultrasonic transducers  250   a  are arranged in order inside the sloped surface. Such arrangement of the plurality of first ultrasonic transducers  250   a  allows the first probe  211  to transmit the first ultrasonic beam  251   a  to a target located on the central axis of the round through hole (the central axis of the probe). 
     The second probe  212  is an appliance that transmits and receives, through the front part thereof which contacts the living body, a second ultrasonic beam  251   b  to obtain a sonogram, which is an image of the inside of the living body. The second probe  212  includes a plurality of second ultrasonic transducers  250   b  as illustrated in  FIG.  1   . 
     The second probe  212  is a columnar member inserted to the round through hole defined in the first probe  211  and detachably attached to the first probe  211 . The first probe  211  and the second probe  212  are used usually with the second probe  212  attached to the first probe  211 . The plurality of second ultrasonic transducers  250   b  are arranged in order inside the front part of the second probe  212 . 
     Note that the forms of the first probe  211  and the second probe  212  and the arrangements of the ultrasonic transducers  250   a  and  250   b  are not limited to this and may be altered as appropriate. Further, the first probe  211  and the second probe  212  may include a damper, an acoustic matching layer, an acoustic lens, and the like (not illustrated). A damper is a member that curtails the ultrasonic waves produced by the ultrasonic transducers  250   a  and  250   b  from being transmitted backward. An acoustic matching layer is a member for decreasing the difference in acoustic impedance between the ultrasonic transducers  250   a  and  250   b  and the living body. An acoustic lens is a device that focuses the ultrasonic beam  251   a  and  251   b , which will be described later. 
     Each of the ultrasonic transducers  250   a  and  250   b  is a device having a piezoelectric effect, including, for example, zirconate titanate, poly(vinylidene fluoride), quartz crystal, or the like and produces an ultrasonic wave by vibrating in response to an electric signal applied through the wire  231  or  232 . 
     In particular, the plurality of first ultrasonic transducers  250   a  are devices to emit a first ultrasonic beam  251   a  that breaks microcapsules  162  in the filling liquid  161  when applied to the balloon  170  filled with the filling liquid  161  and occluding a tubular organ. The plurality of first ultrasonic transducers  250   a  generate an ultrasonic waves by vibrating in response to an electric signal applied thereto through the wire  231 . The ultrasonic waves are emitted from the front part of the first probe  211  as a first ultrasonic beam  251   a.    
     Note that it is preferable that the first ultrasonic beam  251   a  be an ultrasonic beam having a higher energy than that of the second ultrasonic beam  251   b  to ensure destruction of the microcapsules  162  and, for example, a line-focused ultrasonic beam is preferably used. 
     The plurality of second ultrasonic transducers  250   b  are devices for transmitting and receiving a second ultrasonic beam  251   b  to obtain a sonogram taken inside the living body. 
     The plurality of second ultrasonic transducers  250   b  produce ultrasonic waves by vibrating in response to an electric signal. The ultrasonic wave is emitted from the front part of the second probe  212  as a second ultrasonic beam  251   b . Further, upon receiving the second ultrasonic beam  251   b  reflected inside the living body, the plurality of second ultrasonic transducers  250   b  output an electrical signal in accordance with the received second ultrasonic beam  251   b  as a reception signal. 
     The first ultrasonic wave control unit  221  is a unit that controls the first probe  211  and includes an input device  261 , a controller  262 , and a transmitter  263 , as  FIG.  3    illustrates the functional configuration thereof. 
     The input device  261  is operated by the user for inputting an instruction to start or finish the emission of the first ultrasonic beam  251   a , setting values of various kinds, and the like. The input device  261  physically includes, for example, a button, a switch, and the like. 
     The controller  262  controls the transmitter  263  in accordance with the operation on the input device  261 , signals from various sensors (not illustrated), and the like. 
     Under the control by the controller  262 , the transmitter  263  controls the plurality of first ultrasonic transducers  250   a  to cause the first probe  211  to emit the first ultrasonic beam  251   a.    
     In particular, the transmitter  263  outputs a transmission signal, which is an electric signal, through the wire  231  to each of the plurality of first ultrasonic transducers  250   a  to control the plurality of first ultrasonic transducers  250   a . Each of the plurality of first ultrasonic transducers  250   a  thereby acquires the transmission signal from the transmitter  263  and produces an ultrasonic wave in accordance with the acquired signal. The individual ultrasonic waves produced by the respective first ultrasonic transducers  250   a  compose a first ultrasonic beam  251   a , which is emitted from the first probe  211 . 
     The second ultrasonic wave control unit  222  is a unit that controls the second probe  212  and includes an input device  271 , a controller  272 , a transmitter  273 , a receiver  274 , a sonogram generator  275 , and a display  276 . 
     The input device  271  is operated by the user for inputting an instruction to start or finish the emission of the second ultrasonic beam  251   b ; an instruction to start or finish the display of a sonogram; setting values of various kinds; and the like. The input device  271  physically includes, for example, a button, a switch, and the like. Note that the input device  271  together with the display  276  may form a touch panel. 
     The controller  272  controls the transmitter  273 , the receiver  274 , and the like in accordance with the operation on the input device  271 , signals from various sensors (not illustrated), and the like. 
     Under the control by the controller  272 , the transmitter  273  controls the plurality of second ultrasonic transducers  250   b  to cause the second probe  212  to emit the second ultrasonic beam  251   b.    
     In particular, the transmitter  273  outputs a transmission signal, which is an electric signal, through the wire  232  to each of the plurality of second ultrasonic transducers  250   b  to control the plurality of second ultrasonic transducers  250   b . Each of the plurality of second ultrasonic transducers  250   b  thereby acquires the transmission signal from the transmitter  273  and produces an ultrasonic wave in accordance with the acquired signal. The individual ultrasonic waves produced by the respective first ultrasonic transducers  250   b  compose a first ultrasonic beam  251   b , which is emitted from the first probe  212 . 
     Under the control by the controller  272 , the receiver  274  generates echo data in accordance with the second ultrasonic beam  251   b  reflected inside the living body on the basis of the reception signals outputted by the plurality of second ultrasonic transducers  250   b . In particular, the receiver  274  generates the echo data by acquiring the reception signals outputted by the plurality of second ultrasonic transducers  250   b  through the wire  232  and applying phasing addition processing and the like to the acquired reception signals. 
     The sonogram generator  275  generates display data to display a sonogram on the display  276  on the basis of the echo data generated by the receiver  274 . In particular, the sonogram generator  275  generates the display data by acquiring the echo data generated by the receiver  274  from the receiver  274  and applying appropriate image processing to the acquired echo data. The image processing herein is, for example, processing for allowing the display  276  to display an image of a predetermined mode, such as B-mode image or 2D image. 
     The controller  272 , the transmitter  273 , the receiver  274 , and the sonogram generator  275  may physically include, for example, one or more processors, RAM, ROM, flash memory, dedicated electric circuits, and the like, which may be combined as appropriate. 
     The display  276  displays the sonogram represented by the display data generated by the sonogram generator  275 . In particular, the display  276  acquires the display data from the sonogram generator  275  and displays the sonogram represented by the acquired display data. The display  276  may physically include, for example, a liquid crystal panel, a liquid crystal drive circuit, a back panel, and the like. 
     The configuration of the medical system  1  according to an embodiment has been described above. An operation of the medical system  1  according to the present embodiment will be described below. 
     As to the present embodiment, an operation of the medical system  1  will be described with an example of application thereof to a treatment of congenital diaphragmatic hernia. Congenital diaphragmatic hernia is an illness in which the diaphragm of a fetus  412  has a hole  450 , through which intraperitoneal organs  413  such as small intestine, large intestine, and stomach migrate into the thoracic cavity  411 , obstructing the growth of the fetal lungs  414   a  and  414   b , as illustrated in  FIG.  4   , which is an enlarged view of the vicinity of the fetal thoracic cavity  411 .  FIG.  4    illustrates an example in which the growth of the left lung  414   a , shaded by oblique lines, is obstructed. 
     Note that the medical system  1  can be suitably used not only for the treatment of congenital diaphragmatic hernia but also for the treatment of various illnesses in which it is effective to occlude a tubular organ of the living body with a balloon  170  and to terminate the occlusion. Further, the living body is not limited to a living human body but may be a living animal body. 
     (Occlusion of a Tubular Organ) 
     The user starts the operation of the imaging unit  125  by operating the input device  131  of the endoscope control unit  130 . This causes the image taken by the camera of the imaging unit  125  to be displayed on the display  135 . 
     In particular, the imaging controller  133  receives an instruction from the controller  132  to start operation of the imaging unit  125 , based on the operation of the input device  131 . In response to the instruction, the imaging controller  133  causes the light of the imaging unit  125  to emit light and causes the camera of the imaging unit  125  to take an image. The camera of the imaging unit  125  outputs image data that represent the image taken. The display image generator  134  acquires the image data from the imaging unit  125  and generates display data based on the acquired image data. The display  135  acquires the display data from the display image generator  134  and displays the image represented by the acquired display data. 
     Holding the operation part  122 , the user inserts the sheath body  111  into the uterus  320  through an insertion hole formed in the maternal abdomen  310 , as illustrated in  FIG.  5   , wherein the insertion part  121 , the first catheter  155 , and the second catheter  165  are arranged in the sheath body  111  by being inserted therethrough in advance (see  FIG.  1   ). The user at this time inserts the sheath body  111  into the uterus  320  while the balloon  170  attached to the front end of the second catheter  165  is not exposed at the front end of the sheath body  111  but housed in the sheath body  111 . 
     The user inserts the front part  111   b  of the sheath body  111  into the fetal trachea  410 , which is the target tubular organ to be occluded, by operating the operation part  122  while viewing the image displayed on the display  135 . When the user has a poor vision in the endoscope  120  during the insertion of the sheath body  111 , the user causes the flush liquid  151  to spout from the front end of the sheath body  111  as appropriate by operating the first syringe  150 . When the front part  111   b  of the sheath body  111  reaches the fetal trachea  410 , the user pushes the second catheter  165  in the direction of insertion and disposes the balloon  170  in such a way that the balloon  170  is exposed at the front end of the sheath body  111  (see  FIG.  5   ). 
     While checking the state of inflation of the balloon  170  on the image taken by the endoscope  120  and displayed on the display  135 , the user injects the filling liquid  161  into the balloon  170  by manually operating the second syringe  160  (by pushing down the plunger). 
     When the balloon  170  filled with the filling liquid  161  inflates and occludes the trachea  410  (see  FIG.  6   ), the user stops operating the second syringe  160  and stops injecting the filling liquid  161  to the balloon  170 . 
     The user pulls on the second catheter  165  while holding the operation part  122  to pull out the second catheter  165  alone from the sheath  110  with the sheath body  111  remaining in the maternal body. At this time, since the balloon  170  occludes the trachea  410 , the balloon  170  is pressed against the trachea  410  while applying a certain force on the trachea  410 . Thus, the balloon  170  is detached from the front end of the second catheter  165  simply by pulling out the second catheter  165 . 
     Note that, due to the function of the backflow check valve of the balloon  170 , the filling liquid  161  does not flow out of the balloon  170  but remains in the balloon  170  even when the second catheter  165  is pulled out. 
     After checking the state of inflation of the balloon  170  on the image taken by the endoscope  120  and displayed on the display  135  and checking that the occlusion of the fetal trachea  410  is maintained, the user pulls the operation part  122  to pull out from the maternal body the sheath body  111 , wherein the insertion part  121  of the endoscope  120  and the first catheter  155  remain inserted through the sheath body  111  (see  FIG.  7   ). 
     The user stops the operation of the imaging unit  125  by operating the input device  131  of the endoscope control unit  130 . In particular, the imaging controller  133  receives from the controller  132  an instruction to stop the operation of the imaging unit  125 , based on the operation of the input device  131 . In response to the instruction, the imaging controller  133  stops the light of the imaging unit  125  emitting light and stops the camera taking an image. This concludes the surgical treatment for occluding the fetal trachea  410 . 
     Thereafter, the fetal trachea  410  is kept occluded for a certain period of time. During the time when the trachea  410  is occluded, the pressure of the lung liquid stimulates the growth of the fetal lung  414   a  and pushes the intraperitoneal organs  413  that entered the thoracic cavity  411  back to the original positions in the peritoneal cavity (see  FIG.  8   ). 
     The period during which the trachea is occluded is generally about 34 weeks. Approximately after this period, the occlusion of the trachea needs to be terminated in preparation for pulmonary respiration after birth. 
     &lt;Termination of the Occlusion of the Tubular Organ&gt; 
     The user operates the input device  271  of the second ultrasonic wave control unit  222  to cause the ultrasonic device  200  to start displaying a sonogram. This allows the user to have a sonogram including an image of the balloon  170  occluding the fetal trachea  410  displayed on the display  276  by applying the second probe  212  on the proper part of the maternal abdomen  310 . 
     In particular, the transmitter  273  and the receiver  274  receive an instruction from the controller  272  to start displaying the sonogram, based on the operation of the input device  271 . 
     In response to this instruction, the transmitter  273  causes the second probe  212  to emit a second ultrasonic beam  251   b  by controlling the plurality of second ultrasonic transducers  250   b . The plurality of second ultrasonic transducers  250   b  receive the second ultrasonic beam  251   b  reflected, for example, inside the maternal body and outputs reception signals in accordance with the received second ultrasonic beam  251   b.    
     The receiver  274  acquires the reception signals from the plurality of second ultrasonic transducers  250   b  and generates echo data based on the acquired reception signals. The sonogram generator  275  acquires the echo data from the receiver  274  and generates display data based on the acquired echo data. The display  276  acquires the display data from the sonogram generator  275  and displays a sonogram represented by the acquired display data. 
     Thus, a sonogram of the inside of the maternal body is displayed on the display  276  by applying the second probe  212  to the maternal abdomen  310 . The user adjusts the position of the second probe  212  viewing the sonogram to apply the second probe  212  to the proper part of the maternal abdomen  310  and thereby a sonogram including an image of the balloon  170  occluding the fetal trachea  410  is displayed on the display  276 . 
     Note that, for the processing of displaying such a sonogram as described above, various conventional processing techniques may be applied as appropriate. 
     When the balloon  170  is displayed approximately in the center of the sonogram, the user operates the input device  261  of the first ultrasonic wave control unit  221  to cause the first probe  211  to start emitting the first ultrasonic beam  251   a  as illustrated in  FIG.  9   . Note that the second ultrasonic beam  251   b  is not illustrated in  FIG.  9    to simplify the drawing. 
     In particular, the transmitter  263  receives from the controller  262  an instruction to start emitting the first ultrasonic beam  251   a , based on the operation of the input device  261 . In response to the instruction, the transmitter  263  causes the first probe  211  to emit the first ultrasonic beam  251   a  by controlling the plurality of first ultrasonic transducers  250   a.    
     As described above, the plurality of first ultrasonic transducers  250   a  are arranged inside the sloped surface of the front part of the first probe  211  surrounding the outer circumference of the second probe  212 . Therefore, the first ultrasonic beam  251   a  can be applied to the balloon  170  by causing the first probe  211  to emit the first ultrasonic beam  251   a  when the balloon  170  is displayed in the center of the sonogram, as illustrated in  FIG.  10 A , which is an enlarged view of the vicinity of the balloon  170  and the fetal trachea  410 . 
     At this time, the first ultrasonic beam  251   a  may be applied for example, for a period of 2.5 ms repeatedly every 50 ms at an applied voltage value 200 Vpp, owing to the operation of the plurality of first ultrasonic transducers  250   a  under the control by the transmitter  263 . Such a mode of application of the first ultrasonic beam  251   a  may be set in advance or may be set by the user operating the input device  261 . 
     When the first ultrasonic beam  251   a  is applied to the balloon  170 , the microcapsules  162  contained in the filling liquid  161  in the balloon  170  are gradually broken and limonene is let out to the filling liquid  161 , as illustrated in  FIG.  10 B . In  FIG.  10 B , the broken microcapsules  162  are depicted by broken lines and the state in which limonene is let out to the filling liquid  161  is depicted by oblique lines. 
     Limonene let out to the filling liquid  161  comes into contact with the balloon  170  and the balloon  170  dissolves where the contact is made. As a result, the balloon  170  is broken as illustrated in  FIG.  10 C .  FIG.  10 C  illustrates an example in which the balloon  170  is broken at the front end thereof (the end closer to the fetal lungs  414   a  and  414   b ). 
     As the filling liquid  161  is let out of the balloon  170  through the broken part, the balloon  170  deflates. This terminates the occlusion of the trachea  410  by the balloon  170  (see  FIG.  10 D ). The deflated balloon  170  is discharged through the fetal mouth to the uterus  320 , together with the lung liquid built up in the fetal lungs  414   a  and  414   b  due to the occlusion till then. 
     The user checks that the balloon  170  is broken on the sonogram and causes the first probe  211  to stop emitting the first ultrasonic beam  251   a  by operating the input device  261  of the first ultrasonic wave control unit  221 . The user also causes the second probe  212  to stop emitting the second ultrasonic beam  251   b  by operating the input device  271  of the second ultrasonic wave control unit  222  and stops the display of the sonogram. 
     In particular, the transmitter  263  of the first ultrasonic wave control unit  221  receives from the controller  262  an instruction to stop emitting the first ultrasonic beam  251   a , based on the operation of the input device  261 . In response to the instruction, the transmitter  263  causes the first probe  211  to stop emitting the first ultrasonic beam  251   a  by controlling the plurality of first ultrasonic transducers  250   a.    
     Further, the transmitter  273  and the receiver  274  of the second ultrasonic wave control unit  222  receive from the controller  272  an instruction to stop displaying the sonogram, based on the operation of the input device  271 . In response to the instruction, the transmitter  273  causes the second probe  212  to stop emitting the second ultrasonic beam  251   b  by controlling the plurality of second ultrasonic transducers  250   b  and the receiver  274  stops processing such as the receiving the reception signals. 
     Note that the duration of time in which the first ultrasonic beam  251   a  is being emitted from the first probe  211  to the balloon  170  before the balloon  170  is broken is, for example, about 1 to several seconds. 
     As described above, according to the present embodiment, the transmitter  263  of the first ultrasonic wave control unit  221  causes the first probe  211  to emit the first ultrasonic beam  251   a  that breaks the microcapsules  162  contained in the filling liquid  161  when applied to the balloon  170  filled with filling liquid  161  and occluding the fetal trachea  410 . Further, a substance that dissolves the balloon  170  is encapsulated in the microcapsules  162 . 
     This makes it possible to break the microcapsules  162  contained in the filling liquid  161  by applying ultrasonic waves to the balloon  170  filled with the filling liquid  161  and occluding the fetal trachea  410  and to cause the balloon  170  to be dissolved by limonene let out of the broken microcapsules  162 . 
     As described above, the termination of the occlusion of the fetal trachea  410  by the balloon  170  requires no surgical operation and therefore is minimally invasive. Further, unlike endoscopic surgery, it is not necessary to set up a system of medical specialists and the like and therefore it is relatively easy to perform the termination. Further, the balloon  170  can assuredly be broken by limonene. Therefore, it is possible to terminate the occlusion of the fetal trachea  410  by the balloon  170  in a minimally invasive, easy, and assured way. 
     According to the present embodiment, the user operates the second syringe  160  to inject the filling liquid  161 , which is guided through the second catheter  165  to the balloon  170 . This allows the balloon  170  to be filled with the filling liquid  161  and to inflate, thereby occluding the fetal trachea  410 . 
     According to the present embodiment, the balloon  170  is made of latex. Further, limonene, which has a property of dissolving rubber such as latex, is used as a substance to dissolve the balloon  170 . Limonene is a naturally derived substance and thus very unlikely to adversely affect a human body. 
     An embodiment of the present disclosure has been described above but the present disclosure is not limited to this embodiment and may be modified, for example, in the following ways. 
     For example, the embodiment has been described with an example in which the medical system  1  includes an endoscopic device  100  and an ultrasonic device  200  physically separate from each other as illustrated in  FIG.  1   . However, the medical system may as a whole include the features included by the medical system  1 . For example, the first ultrasonic wave control unit  221  and the second ultrasonic wave control unit  222  as well as the endoscope control unit  130  may be integrated physically into one control device that controls the entire medical system. The same advantageous effects as according to the embodiment can be achieved also according to this modified example. 
     For example, limonene is an example of a substance that dissolves the balloon  170  made of latex. Further, the material for the balloon  170  may be selected as appropriate and a substance that dissolves the balloon  170  made of the material selected as appropriate is preferably encapsulated in the microcapsules  162 . A naturally derived essential oil having a property of dissolving rubber such as latex may be used as appropriate as the substance to dissolve the balloon  170 . Among the naturally derived essential oils of this kind apart from limonene are, for example, menthol, geraniol, carotenoid (plant pigment), fat-soluble vitamins (vitamins A, D, E, and K), and naturally occurring compounds called terpenoids, which have isoprene as constituent units, such as coenzyme Q. The same advantageous effects as according to the embodiment can be achieved also according to this modified example. 
     For example, the probe that emits the ultrasonic beam has been described with an example including the first probe  211  and the second probe  212  that separately perform the emissions of the first ultrasonic beam  251   a  and the second ultrasonic beam  251   b , respectively, and other functions. However, a probe that can integrally process the emissions of the first ultrasonic beam  251   a  and the second ultrasonic beam  251   b  and other functions may be used. In such a case, the first ultrasonic wave control unit  221  and the second ultrasonic wave control unit  222  may be integrated into one ultrasonic wave control unit. Further, there may be a single first ultrasonic transducer  250   a  and a single second ultrasonic transducer  250   b . Further, all of one or more first ultrasonic transducers  250   a  and one or more second ultrasonic transducers  250   b  or at least a part of a plurality of first ultrasonic transducers  250   a  and a plurality of second ultrasonic transducers  250   b  may have a plurality of functions at the same time among the function of generating an ultrasonic wave for emitting the first ultrasonic beam  251   a , the function of generating an ultrasonic wave for emitting the second ultrasonic beam  251   b , and the function of receiving the second ultrasonic beam  251   b . The same advantageous effects as according to the embodiment can be achieved also according to this modified example. 
     For example, according to the embodiment, an example in which the first probe  211  is caused to emit a first ultrasonic beam  251   a  while the balloon  170  is displayed in the center of the sonogram but the first ultrasonic beam  251   a  may be emitted to the balloon  170  by designating the position of the balloon  170 . In particular, the user may identify the position of the balloon  170  on the basis of the image of the balloon  170  displayed on the display  276  of the second ultrasonic wave control unit  222  and, by operating the input device  261  of the first ultrasonic wave control unit  221 , designate the position of the balloon  170  on the transmitter  263  by way of the controller  262 . The transmitter  263  may then control the plurality of first ultrasonic transducers  250   a  in such a way that the first ultrasonic beam  251   a  is emitted to the designated position. The same advantageous effects as according to the embodiment can be achieved also according to this modified example. Further, as the first ultrasonic beam  251   a  can be applied assuredly to the balloon  170 , the occlusion of the tubular organ by the balloon  170  can be terminated more assuredly. 
     The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled. 
     This application claims the benefit of Japanese Patent Application No. 2016-126601, filed on Jun. 27, 2016, the entire disclosure of which is incorporated by reference herein. 
     REFERENCE SIGNS LIST 
     
         
           1  Medical system 
           100  Endoscopic device 
           110  Sheath 
           111  Sheath body 
           111   a  Rear part 
           111   b  Front part 
           112  Connecter 
           113 ,  114  Insertion port part 
           120  Endoscope 
           121  Insertion part 
           122  Operation part 
           123  Wire 
           125  Imaging unit 
           130  Endoscope control unit 
           131  Input device 
           132  Controller 
           133  Imaging controller 
           134  Display image generator 
           135  Display 
           150  First syringe 
           151  Flush liquid 
           155  First catheter 
           156  Spout opening 
           160  Second syringe 
           161  Filling liquid 
           162  Microcapsule 
           165  Second catheter 
           170  Balloon 
           200  Ultrasonic device 
           210  Probe 
           211  First probe 
           212  Second probe 
           220  Control unit 
           221  First ultrasonic wave control unit 
           222  Second ultrasonic wave control unit 
           231 ,  232  Wire 
           250   a  First ultrasonic transducer 
           250   b  Second ultrasonic transducer 
           251   a  First ultrasonic beam 
           251   b  Second ultrasonic beam 
           261  Input device 
           262  Controller 
           263  Transmitter 
           271  Input device 
           272  Controller 
           273  Transmitter 
           274  Receiver 
           275  Sonogram generator 
           276  Display 
           310  Abdomen 
           320  Uterus 
           410  Trachea 
           411  Thoracic cavity 
           412  Diaphragm 
           413  Intraperitoneal organ 
           414   a ,  414   b  Lung 
           450  Hole