Patent Publication Number: US-2023149043-A1

Title: Cannulation method, information processing system and medical system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to U.S. Provisional Application Nos. 63/280,716 filed Nov. 18, 2021, and 63/294,597 filed Dec. 29, 2021, the entire contents of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     A technique called endoscopic retrograde cholangiopancreatography (ERCP) has been known that captures an X-ray image or a CT image of biliary duct by inserting a cannula into a biliary duct from a treatment tool channel of an endoscope, injecting a contrast agent from the cannula, and performing X-ray imaging or CT imaging. U.S. Patent Application Publication No. 2010/0056910 discloses a procedure to approach a biliary duct using a flexible guide wire in order to allow for easy insertion without inhibiting drainage of pancreatic juice. 
     SUMMARY 
     An aspect of the present disclosure relates to a cannulation method includes: inserting an endoscope into a duodenum, bringing a distal end section of the endoscope to a position where a duodenal papilla is within a field of view of the endoscope, promoting secretion of pancreatic juice or bile by administering a drainage stimulant, determining an amount of relaxation of the duodenal papilla, and performing cannulation into a biliary duct through the duodenal papilla where the amount of relaxation is greater than a predetermined amount. 
     Another aspect of the present disclosure relates to an information processing system includes a processor comprising hardware. The processor is configured to acquire an endoscope image from an endoscope, the endoscope image showing a duodenal papilla, determine an amount of relaxation of the duodenal papilla based on the acquired endoscope image, and determine whether or not to administer a drainage stimulant promoting secretion of pancreatic juice or bile based on the determined amount of relaxation. 
     Still another aspect of the present disclosure relates to a medical system including: an information processing system described above; and the endoscope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows organs and tissues involved in the ERCP procedure. 
         FIG.  2    shows a flow of the ERCP procedure. 
         FIG.  3    shows a schematic diagram of the form of papillary portion viewed directly from the front. 
         FIG.  4    shows classification types of biliary and pancreatic ducts corresponding to endoscope images of the papillary portion. 
         FIG.  5    explains a cannulation method of the present embodiment. 
         FIG.  6    schematically shows a relaxed state and an unrelaxed state of the papillary portion. 
         FIG.  7    is a flowchart explaining the cannulation method of the present embodiment. 
         FIG.  8    is a flowchart explaining a specific example of the cannulation method of the present embodiment. 
         FIG.  9    is a flowchart explaining a specific example of the cannulation method of the present embodiment. 
         FIG.  10    is a flowchart explaining a specific example of the cannulation method of the present embodiment. 
         FIG.  11    shows a configuration example of an information processing system of the present embodiment. 
         FIG.  12    is a flowchart explaining a process of the present embodiment. 
         FIG.  13    explains a process using a trained model. 
         FIG.  14    is a flowchart explaining a process of the present embodiment when the trained model is used. 
         FIG.  15    explains another process using the trained model. 
         FIG.  16    is a flowchart explaining another process of the present embodiment when the trained model is used. 
         FIG.  17    explains another process using the trained model. 
         FIG.  18    explains another process using the trained model. 
         FIG.  19    is a flowchart explaining a process of the present embodiment when electrically-driven endoscopic operation is used. 
         FIG.  20    is a flowchart explaining a process of the present embodiment when electrically-driven endoscopic operation is used. 
         FIG.  21    shows a configuration example of a medical system of the present embodiment. 
         FIG.  22    is a flowchart of a procedure in the present embodiment. 
         FIG.  23    shows the vicinity of the distal end of an endoscope positioned by an overtube and a balloon. 
         FIG.  24    is a schematic view of an endoscope including a bending section and a driving mechanism thereof. 
         FIG.  25    shows a detailed configuration example of a forward/backward drive device. 
         FIG.  26    is a perspective view of a connecting section including a rolling drive device. 
         FIG.  27    shows a detailed configuration example of a distal end section of an endoscope including a raising base of a treatment tool. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being “connected” or “coupled” to a second element, such description includes embodiments in which the first and second elements are directly connected or coupled to each other, and also includes embodiments in which the first and second elements are indirectly connected or coupled to each other with one or more other intervening elements in between. 
     Explanation of ERCP 
     The present embodiment relates to a cannulation method and an information processing system for performing ERCP and the like. ERCP stands for Endoscopic Retrograde Cholangiopancreatography. First, before describing the present embodiment, the details of procedure of ERCP is described below. 
       FIG.  1    shows organs and tissues involved in the ERCP procedure. The organs include a multiple types of tissues, forming a unique structure with a specific function. In  FIG.  1   , the liver, gallbladder, pancreas, esophagus, stomach, and duodenum are shown as organs. Tissues are formed by related cells combined, and examples include blood vessels, muscles, skin, and the like. In  FIG.  1   , a biliary duct and a pancreatic duct are shown as tissues. 
     The biliary duct is the target of the ERCP procedure. The biliary duct is a pipeline for allowing the bile produced in the liver to flow into the duodenum. When approaching the biliary duct using an endoscope, a treatment tool inserted into the channel of the endoscope is inserted to the biliary duct from the papillary portion of the duodenum while holding the endoscope at the position of the duodenum. Hereinafter, the papillary portion of the duodenum is simply referred to as a papillary portion. The papillary portion is a region including an opening of the luminal tissue with respect to the duodenum. Not only the opening but also the structure around the opening is referred to as a papillary portion. The opening of the luminal tissue is the opening of a common duct with respect to the duodenum. The common duct is formed as the confluence of the biliary duct and pancreatic duct. However, as described later, the papillary portion largely varies between individuals. For example, in some cases, the biliary duct opens directly to the duodenum without being merged with the pancreatic duct. In this case, the opening of the luminal tissue is the opening of the biliary duct. 
       FIG.  2    shows a flow of the ERCP procedure. In ERCP, a side-viewing type endoscope in which a camera, an illumination lens, and an opening of a treatment tool channel are provided on a side surface of a distal end section of the endoscope is used. The camera is also referred to as an imaging device. 
     In the endoscope insertion step, the insertion section of the endoscope is inserted from the mouth to the duodenum through the esophagus and stomach. At this time, the insertion section is inserted until the papillary portion becomes roughly visible in the field of view of the endoscope. Next, in the positioning step, the position of the endoscope is adjusted relative to the papillary portion. Specifically, the position of the distal end section of the endoscope is adjusted so that the papillary portion is within the imaging range of the camera of the endoscope. Alternatively, the position of the distal end section of the endoscope is adjusted so that the camera of the endoscope is facing directly front of the papillary portion and the papillary portion appears in the center of the field of view. 
     Then, in the cannulation step, a cannula is inserted from the papillary portion into the biliary duct. Specifically, the cannula is inserted into the treatment tool channel of the endoscope so that the cannula protrudes from the channel opening of the distal end section of the endoscope. The distal end of the cannula is inserted into the common duct from the opening of the common duct, and the cannula is further inserted through the confluence of the biliary duct and the pancreatic duct toward the direction of the biliary duct. Cannulation refers to insertion of a cannula into a body. A cannula is a medical tube that is inserted into a body for medical purposes. 
     Next, in the contrast radiography and imaging step, a contrast agent is injected into the cannula and poured into the biliary duct through the distal end of the cannula. By performing X-ray or CT imaging in this state, an X-ray image or a CT (Computed Tomography) image showing the biliary duct, gallbladder, and pancreatic duct can be obtained. The procedure of ERCP has been described. After the procedure, various treatments are performed according to the results of diagnosis based on the X-ray image or CT image. An example of the treatment is described below. 
     In a guide wire insertion step, a guide wire is inserted into a cannula so that the guide wire is protruded from the distal end of the cannula, and the guide wire is inserted into the biliary duct. In a cannula removing step, the cannula is removed while leaving the guide wire inside the biliary duct. As a result, only the guide wire protrudes from the distal end section of the endoscope, indwelling in the biliary duct. Next, in a treatment tool insertion step, the treatment tool is inserted into the biliary duct along the guide wire. An example of a treatment tool is a basket or stent. The basket is used with a catheter. While allowing the guide wire to pass through the catheter, the catheter is inserted into the biliary duct along the guide wire. A basket made of a plurality of metal wires is inserted into the biliary duct from the distal end of the catheter, an object to be removed, such as a gallstone, is placed in the basket and held, and the object to be removed is taken out from the biliary duct by removing the basket and catheter in this state from the biliary duct. A stent is also used in a similar manner with a catheter and inserted into the biliary duct from the distal end of the catheter. The narrow portion of the biliary duct can be widened by inserting a stent; further, by keeping the stent therein, the narrow portion is held in a widened state by the indwelling stent. 
     The ERCP procedure is performed as described above. The cannulation step of inserting the cannula has the following challenges. For example,  FIG.  3    is a schematic diagram of the form of the papillary portion viewed directly from the front. As shown in  FIG.  3   , unique structures exist around the opening of the papillary portion. Specifically, structures respectively called a frenulum, a papillary protrusion, an encircling fold, circular folds, and an oral protrusion are present around the opening, which is a major papilla. As shown in  FIG.  3   , the opening of the papillary portion is usually closed. In some cases, the opening is tight closed, making it impossible to insert the cannula smoothly. The opening into which the cannula cannot be inserted is incised using a procedure called endoscopic spincterotomy (EST) and cannulated. 
     Additionally, the shapes of the opening and its surroundings in the papillary portion differ from individual to individual. For example,  FIG.  4    shows classification patterns for the papillary portion and examples of endoscope images observed in the respective classification patterns. As shown in  FIG.  4   , the classification patterns based on the paths of the biliary and pancreatic ducts include, for example, a common channel type, a separate type, an onion type, and a septal type. The classification patterns based on the opening of the papillary portion include a separate opening type, an onion type, a nodular type, a villous type, a flat type, and a vertically elongated type. 
     As such, the opening of the papillary portion is usually closed and the shapes of the opening and its surroundings differ from individual to individual, so that the cannulation step involves difficulty in smoothly inserting the cannula. In this regard, U.S. Patent Application Publication No. 2010/0056910 mentioned above discloses a procedure that allows for easy insertion without inhibiting drainage of pancreatic juice by approaching the biliary duct using a flexible guide wire. However, the publication does not suggest any procedure that facilitates insertion of the cannula into the opening prior to insertion of the cannula. 
     Cannulation Method 
     Hence, in the present embodiment, a drainage stimulant is administered to promote secretion of pancreatic juice or bile in a step prior to the cannulation. For example, prior to insertion of the cannula, an agent that promotes pancreatic juice, such as secretin, is sprayed to the papillary portion as a drainage stimulant. Alternatively, prior to insertion of the endoscope, a drainage stimulant may be administered orally. Such a step of promoting the secretion of pancreatic juice or bile by administration of the drainage stimulant can accelerate the secretion of pancreatic juice or bile to thereby loosen the region around the papillary portion and expand the opening. Specifically, the sphincter of Oddi in the papillary portion is relaxed, which widens the opening and facilitates insertion of the cannula into the opening. This allows even inexperienced operators or the like to easily insert the cannula into the opening of the papillary portion, facilitating an easier ERCP procedure. 
       FIG.  5    explains the cannulation method of the present embodiment. In  FIG.  5   , a step of inserting the endoscope into the duodenum is performed, followed by a step of positioning the endoscope whereby the distal end section thereof is brought to the position where the papillary portion is in the field of view of the endoscope. For example, a step is performed where an operator recognizes the papillary portion from an endoscope image and positions the endoscope to the position where the papillary portion can be seen. Then, a step is performed where the drainage stimulant is administered to promote the secretion of pancreatic juice or bile. For example, a step is performed where an agent that promotes the secretion of pancreatic juice, such as secretin, is sprayed to the papillary portion from the distal end section of the endoscope. The drainage stimulant may be any agent that promotes the secretion of at least one of pancreatic juice and bile, and may be an agent that promotes the secretion of both pancreatic juice and bile. Then, a step is performed where a state of relaxation of the lumen in the papillary portion is confirmed, alternatively referred to as determining an amount of relaxation of the lumen in the papillary portion. The state of relaxation of the lumen in the papillary portion is, for example, a state of relaxation of the sphincter near the opening of the papillary portion, more specifically a state of relaxation of the sphincter of Oddi present around the papillary portion. In other words, a step is performed where it is confirmed whether the sphincter of Oddi in the papillary portion has been relaxed to allow for insertion of the cannula into the opening of the papillary portion. For example,  FIG.  6    schematically shows a relaxed state and an unrelaxed state of the papillary portion. In an unrelaxed state, the opening is closed and insertion of the cannula is not easy, but in a relaxed state, the sphincter of Oddi is relaxed and open, facilitating insertion of the cannula into the opening (that is, an amount of relaxation can correspond e.g., to a size of the opening and/or an amount of pancreatic juice or bile present in the image(s)). For example, an operator or the like visually or otherwise confirms whether such a relaxed state is present, corresponding to an amount of relaxation. Subsequently, if the relaxed state (amount of relaxation) is greater than some predetermined amount of relaxation (e.g., open more than a predetermined amount) a step of cannulating the biliary duct is performed. That is, a step is performed where the cannula is protruded from the channel opening of the distal end section of the endoscope and the distal end of the cannula is inserted into the relaxed opening to thereby insert the cannula in the direction of the biliary duct. Then, a contrast radiography and imaging step is performed where a contrast agent is injected into the cannula and poured into the biliary duct from the distal end of the cannula. 
       FIG.  7    is a flowchart explaining the cannulation method of the present embodiment. As shown in  FIG.  7   , the cannulation method of the present embodiment includes step S 11  of inserting the endoscope into the duodenum and step S 12  of bringing the distal end section of the endoscope to the position where the papillary portion is in the field of view of the endoscope. These steps S 11 , S 12  may be performed manually by an operator without electrical driving, or may be performed by electrically-driven endoscopic operation, which is detailed below. The cannulation method of the present embodiment further includes step S 13  of promoting the secretion of pancreatic juice or bile by administering the drainage stimulant. Specifically, the drainage stimulant is administered to bring about the secretion of pancreatic juice or bile to thereby, for example, relax the sphincter of Oddi in the papillary portion. The cannulation method further includes step S 14  of confirming a state of relaxation of the lumen in the papillary portion. For example, as shown in  FIG.  6   , it is confirmed whether the papillary portion is in an unrelaxed state or a relaxed state by determining whether the opening is greater than a predetermined size. This confirmation in step S 14  may be performed by an operator visually checking the endoscope image, or may be implemented by a process of estimating a state of relaxation based on an endoscope image using an information processing system  20  of  FIG.  11    described below. The cannulation method further includes step S 15  of performing cannulation into the biliary duct. This cannulation step S 15  may be performed manually by an operator without electrical driving power, or may be performed by electrically-driven endoscopic operation described below. 
     As described above, in the present embodiment, the cannulation method for ERCP includes the step of administering the drainage stimulant to promote the secretion of pancreatic juice or bile. Employing such a step can promote the secretion of pancreatic juice or bile by the drainage stimulant and relax the sphincter or the like in the papillary portion. This allows for easy insertion of the cannula into the opening of the papillary portion in the step of cannulating the biliary duct, facilitating an easier ERCP procedure. 
       FIG.  8    is a flowchart explaining a specific example of the cannulation method of the present embodiment.  FIG.  8    shows a specific example of step S 13  in  FIG.  7   ; in step S 13  of promoting the secretion of pancreatic juice or bile, the drainage stimulant is administered (sprayed) from the endoscope disposed within the duodenum. For example, as shown in  FIG.  5   , an agent administration tube is protruded from the channel opening of the distal end section of the endoscope, and the drainage stimulant is administered from the tube. Specifically, an agent such as secretin is sprayed from the agent administration tube. The cannula may be substituted for this agent administration tube. In this way, the drainage stimulant can be administered to the papillary portion from the endoscope located close to the papillary portion in the duodenum, which allows for more precise administration of the drainage stimulant toward the papillary portion. Thus, this can relax the papillary portion in a more reliable manner, facilitating insertion of the cannula into the opening of the papillary portion. 
     In  FIG.  8   , following step S 12  of bringing the distal end section of the endoscope to the above position, the drainage stimulant is administered from the endoscope to the papillary portion in step S 13  of promoting the secretion of pancreatic juice or bile. For example, while the sequence of the steps in the cannulation method of the present embodiment, such as step  13  of promoting the secretion, may be in any order, in  FIG.  8   , the drainage stimulant is administered from the endoscope to the papillary portion in step S 13  following step S 12  of bringing the distal end section of the endoscope to the above position. This step sequence allows the drainage stimulant to be administered to the papillary portion from the endoscope whose distal end section has been brought to the position where the papillary portion is in the field of view of the endoscope. This allows for even more precise administration of the drainage stimulant toward the papillary portion, making it possible to relax the lumen in the papillary portion in an even more reliable manner. 
       FIG.  9    is a flowchart explaining another specific example of the cannulation method of the present embodiment. In  FIGS.  7  and  8   , step S 13  of promoting the secretion of pancreatic juice or bile is employed following step S 12  of bringing the distal end section of the endoscope to the above position. In  FIG.  9   , in contrast, step S 10  of promoting the secretion of pancreatic juice or bile is employed prior to step S 11  of inserting the endoscope into the duodenum. For example, in  FIG.  9   , step S 10  of promoting the secretion of pancreatic juice or bile employs a step of orally administering the drainage stimulant prior to step S 11  of inserting the endoscope. For example, after a patient has taken the drainage stimulant that stimulates the secretion of pancreatic juice or bile, step S 11  is performed to insert the endoscope into the duodenum, and then step S 12  is performed to bring the distal end section of the endoscope to the position where the papillary portion is in the field of view of the endoscope. Then, step S 14  is performed to confirm a state of relaxation of the lumen in the papillary portion, and step S 15  is performed to cannulate the biliary duct. This step sequence can promote the secretion of pancreatic juice or bile through oral administration of the drainage stimulant prior to the insertion of the endoscope, without needing to provide a mechanism to spray the agent directly to the papillary portion from the distal end section of the endoscope. Thus, the oral administration of the drainage stimulant can relax the lumen in the papillary portion, facilitating insertion of the cannula into the opening of the papillary portion. 
       FIG.  10    is a flowchart explaining another specific example of the cannulation method of the present embodiment. In  FIG.  10   , a dose of the drainage stimulant is determined based on an endoscope image acquired by the endoscope and administered accordingly in step S 13 . For example, a dose of the drainage stimulant is determined based on an amount, luminance, or color of pancreatic juice or bile shown in the endoscope image and administered accordingly. Then, in step S 14 , a state (or amount) of relaxation of the lumen in the papillary portion is confirmed, and upon determining in step S 15  that the lumen is relaxed, cannulation into the biliary duct is performed in step S 16 . On the other hand, upon determining in step S 15  that the lumen is not relaxed, the process returns to step S 13  to administer the drainage stimulant again. 
     As described above, in  FIG.  10   , the dose of the drainage stimulant is determined based on the endoscope image acquired by the endoscope in step  13  of promoting the secretion of pancreatic juice or bile. For example, the dose of the drainage stimulant is determined through a process of determining a state of relaxation based on the endoscope image as described below. Specifically, the endoscope image is input to a trained model to determine a state of relaxation of the lumen in the papillary portion. Alternatively, an operator visually inspects the endoscope image to determine the dose of the drainage stimulant. Upon determining that the lumen in the papillary portion has been relaxed by administration of the determined dose of the drainage stimulant, cannulation into the biliary duct is performed. In this way, the endoscope image acquired by the endoscope can be effectively utilized to relax the lumen in the papillary portion by administration of the appropriate dose of the drainage stimulant determined based on the endoscope image. Thus, the operator can easily insert the cannula into the opening of the papillary portion which has been relaxed by administration of the appropriate dose of the drainage stimulant. 
     In this case, in step S 13  of promoting the secretion of pancreatic juice or bile, the cannulation method of the present embodiment can determine the dose of the drainage stimulant based on at least one of the amount, luminance, or color of pancreatic juice or bile shown in the endoscope image. This allows for using the amount, luminance, or color of pancreatic juice or bile in the endoscope image to determine the dose of the drainage stimulant by which the lumen in the papillary portion can be relaxed. Thus, the lumen in the papillary portion can be relaxed by administration of the appropriate dose of the drainage stimulant, facilitating insertion of the cannula into the opening of the papillary portion. For example, when the amount of pancreatic juice or bile shown in the endoscope image is small, the dose of the drainage stimulant is increased. On the other hand, when the amount of pancreatic juice or bile shown in the endoscope image is large, the dose of the drainage stimulant is reduced. This is because the larger the amount of pancreatic juice or bile, the more relaxed state the papillary portion is considered to be in. Also, when a large amount of pancreatic juice or bile is secreted, light from the light source or the like at the distal end section of the endoscope is reflected by the liquid, so that the luminance of the liquid portion in the endoscope image changes. Thus, the dose of the drainage stimulant can be determined based on the luminance of pancreatic juice or bile. The dose of the drainage stimulant can also be determined by detecting the color of pancreatic juice or bile and determining the amount (drainage amount) of pancreatic juice or bile. For example, the color of bile is yellow, yellow-green, brown, or amber. As such, detection of these colors in the endoscope image allows for determining the amount of pancreatic juice or bile to determine the dose of the drainage stimulant. Also, when pancreatic juice or bile is secreted in the lumen in the papillary portion, the color of the biological tissue in the lumen and the color of pancreatic juice or bile are mixed and displayed in the endoscope image, so that detection of such changes in the color allows for determining the amount of pancreatic juice or bile to determine the dose of the drainage stimulant. 
     The drainage stimulant is, for example, an agent that promotes the secretion of pancreatic juice, which is e.g., secretin. Secretin is a gastrointestinal hormone that is synthesized in the mucous membrane of small intestine and promotes exocrine secretion of bicarbonate from the pancreas. For example, secretin is an agent that promotes the drainage of pancreatic juice. While the cannula is inserted into the biliary duct, the biliary and pancreatic ducts are connected and merged at the confluence. Accordingly, using an agent that promotes the drainage of pancreatic juice is expected to be effective in relaxing the papillary portion. 
     The drainage stimulant may be an agent that promotes the secretion of bile. For example, curcumin is an agent that promotes the drainage of bile. Curcumin is a yellow polyphenol compound contained in turmeric and the like. Also, cholecystokinin (CCK) is an agent that promotes the drainage of both pancreatic juice and bile and thus can be used as an agent to promote bile secretion. CCK is a gastrointestinal hormone that is secreted from the upper small intestine and controls secretion of gastric acid, pancreatic juice, and bile after meals. 
     For example, the sphincter of Oddi in the papillary portion becomes relaxed upon stimulating the drainage of bile and pancreatic juice. Bile and pancreatic juice are drained as the gastrointestinal hormones produced in the duodenum, which are CCK and secretin, respectively, enter the bloodstream and act on the brain. CCK is more effective because it stimulates the drainage of both bile and pancreatic juice. For example, gastrointestinal hormones are peptides, which are difficult to produce in a stable manner. Additionally, intravenous injections are required because they are degraded by digestive fluids when administered orally. On the other hand, secretin is widely used as a pancreatic drainage stimulant and suitable as an agent for relaxing the sphincter of Oddi and facilitating the ERCP. 
     For example, when food is digested in the stomach and reaches the duodenum as acids, secretin is secreted by intestinal cells and carried in the bloodstream to the brain, stimulating the secretion of pancreatic juice from the pancreas. Accordingly, administering secretin to the papillary portion can promote the secretion of pancreatic juice. On the other hand, when lipids reach the duodenal lumen, cholecystokinin-pancreozymin (CCK-PZ) is produced and internally secreted from the duodenum. Then, an elevated blood concentration of CCK-PZ causes the gallbladder to contract, causing more bile to flow into the duodenum. Pancreatic juice rich in digestive enzymes is also produced and externally secreted. These factors act to digest and degrade lipids in the duodenal lumen, bringing it back into the state it was in before the arrival of lipids. Thus, CCK is considered to be capable of promoting the secretion of both pancreatic juice and bile. 
     As described above, secretin is secreted as acids reach the duodenum, and CCK is secreted as lipids reach the duodenum. Accordingly, lipids and acids, either in the form of a liquid mixture thereof or individually, are endoscopically sprayed to the duodenum, and the drainage of bile is visually or otherwise confirmed. Then, cannulation is performed. As such, cannulation can be performed with the sphincter of Oddi relaxed. Additionally, lipids that easily cause secretion of CCK are known, and spraying such lipids from the distal end section of the endoscope or orally administering them prior to the ERCP is expected to promote the secretion of pancreatic juice and bile. 
     It is also possible to administer substances that cause bile itself to drain. Examples of substances effective in stimulating the drainage of bile include curcumin (turmeric or  Curcuma longa ). Curcumin is administered orally prior to implementing the ERCP and the endoscope is inserted. Then, upon confirming that bile is drained from the papillary portion, cannulation is performed. 
     Information Processing System 
     As described with reference to  FIGS.  3  and  4   , the shapes of the opening and its surroundings in the papillary portion differ from individual to individual. Accordingly, it is difficult for operators to determine a state of relaxation of the papillary portion through visual confirmation. For example, inexperienced operators may be unable to properly determine whether the papillary portion has become relaxed. 
     Hence, the present embodiment employs a procedure of estimating a state of relaxation of the lumen in the papillary portion based on an endoscope image to determine whether or not or how much to administer the drainage stimulant.  FIG.  11    shows a configuration example of an information processing system  20  for implementing such a procedure of the present embodiment. 
     As shown in  FIG.  11   , the information processing system  20  includes a processor  30 . The information processing system  20  can further include a storage device  70 . For example, this information processing system  20  can be implemented by a control device  600  of a medical system  10  described below with reference to  FIG.  21   . In this case, the medical system  10  is implemented by an endoscope  100  and the information processing system  20 . In this case, part or all of the information processing system  20  may be, for example, implemented by a drive control device  200  and a video control device  500  of the control device  600 , or by an information processing device, such as a personal computer (PC), provided to the control device  600  separately from the drive control device  200  and the video control device  500 . Alternatively, part or all of the information processing system  20  may be implemented by a server or the like in a cloud system. 
     The processor  30  includes hardware. The hardware of the processor  30  may be implemented by digital circuitry that processes digital signals, or by digital circuitry and analog circuitry that processes analog signals. The processor  30  can also be implemented by one or more circuit devices (ICs) or one or more circuit elements mounted on a circuit board. Specifically, the processor  30  can be implemented by a central processing unit (CPU), for example. However, the processor  30  is not limited to a CPU and may be implemented by any of various processors including a graphics processing unit (GPU) and a digital signal processor (DSP). Alternatively, the processor  30  may be implemented by hardware circuitry including an ASIC. 
     The storage device  70  is a device that stores information, which is e.g., a memory. The storage device  70  as a storage section can be implemented by a semiconductor memory such as SRAM and DRAM. Alternatively, the storage device  70  may be implemented by a magnetic storage device, such as a hard disk drive (HDD), or by an optical storage device. For example, the storage device  70  serves as a working area for processes executed by the processor  30 . For example, the storage device  70  stores computer-readable instructions, and execution of the instructions by the processor  30  implements processing in the respective sections of the information processing system  20 . The instructions as referred to herein may be a set of instructions constituting a program, or may be instructions that direct the hardware circuitry of the processor  30  to operate. 
     The processor  30  includes a processing section  40 . The processor  30  can also include a control section  50 , a display device interface  60 , and an endoscope interface  62 . The processing section  40  performs processes including estimating a state of relaxation of the papillary portion and determining whether or not or how much the drainage stimulant should be administered, e.g., by determining a size of the opening in the image(s) and comparing the same to a predetermined size opening stored in the storage. The control section  50  controls electrically-driven endoscopic operation. Details of the processing section  40  and the control section  50  are described below. 
     The display device interface  60  is an output section to output display images and interfaces with the display device  90 . For example, data of display images generated by the processor  30  are output to the display device  90  via the display device interface  60  and displayed on the display device  90 . The endoscope interface  62  is an image acquisition section and interfaces with endoscope  100 . Specifically, the endoscope interface  62  interfaces with an endoscope processor  108  that performs various processing associated with the endoscope  100 . For example, the processor  30  acquires endoscope images captured by the endoscope  100  via the endoscope interface  62 . In this case, the endoscope processor  108  performs various processing on the endoscope images, such as image processing. The endoscope processor  108  is implemented by the video control device  500  in  FIG.  21    (described below) or the like. The display device  90  can be implemented by, for example, a liquid crystal display (LDC), an organic EL display, or a CRT display. Details of the endoscope  100  are described below. 
       FIG.  12    is a flowchart explaining a process of the present embodiment. As shown in  FIG.  12   , the processor  30  including the hardware (the processing section  40 ; the same applies below) acquires an endoscope image showing the papillary portion  100  from the endoscope  100  (step S 21 ). For example, the processor  30  acquires the endoscope image (endoscope video) captured by the endoscope  100  through the endoscope interface  62 . The processor  30  then estimates a state of relaxation of the lumen in the papillary portion based on the endoscope image acquired (step S 22 ). For example, the processor  30  estimates a state of relaxation of the sphincter near the opening of the papillary portion based on the endoscope image showing the papillary portion, e.g., based on a determined size of the opening in the image(s) and/or an amount of pancreatic juice or bile present in the image(s). The processor  30  then determines whether or not or how much to administer the drainage stimulant that promotes the secretion of pancreatic juice or bile (step S 23 ). For example, the processor  30  determines whether a state of relaxation of the papillary portion requires administration of the drainage stimulant or what dose of the drainage stimulant should be administered to bring about a relaxed state suitable for cannulation. For example, the processor  30  determines whether the papillary portion has been in a relaxed state suitable for cannulation without any administration of the drainage stimulant, or whether the papillary portion will not be in a relaxed state suitable for cannulation without administration of the drainage stimulant. Alternatively, the processor  30  determines whether the papillary portion has been in a relaxed state suitable for cannulation after administration of the drainage stimulant and no additional administration of the drainage stimulant is needed, or whether the papillary portion will not be in a relaxed state suitable for cannulation without additional administration of the drainage stimulant. The processor  30  also determines what dose of the drainage stimulant should be administered to bring about a relaxed state suitable for cannulation, based on conditions of the papillary portion and its surroundings shown in the endoscope image. It should be noted that the processor  30  is required to determine at least one of whether or not to administer the drainage stimulant and how much to administer the drainage stimulant, and may determine both whether or not and how much to administer the drainage stimulant. The processing section  40  performs the process of estimating a state of relaxation of the papillary portion and determining whether or not or how much to administer the drainage stimulant. 
     As described above, in the present embodiment, a state of relaxation of the lumen in the papillary portion is estimated from the endoscope image showing the papillary portion, and whether or not or how much to administer the drainage stimulant is determined. In this way, upon determination that administration of the drainage stimulant is needed, the drainage stimulant is administered to promote the secretion of pancreatic juice or bile, making it possible to relax the sphincter and the like in the papillary portion. Additionally, the determined dose of the drainage stimulant is administered to promote the secretion of pancreatic juice or bile, making it possible to sufficiently relax the sphincter and the like in the papillary portion. This allows for easy insertion of the cannula into the opening of the papillary portion in cannulating the biliary duct, facilitating an easier ERCP procedure. 
     As shown in  FIG.  5   , the storage device  70  stores a trained model  72 . Specifically, the storage device  70  stores a trained model  72  trained to output information about whether or not to administer the drainage stimulant or information about how much to administer the drainage stimulant in response to an endoscope image. The information about whether or not to administer the drainage stimulant is information indicating whether the administration of the drainage stimulant is needed, and may be information about the need for administration itself or information for identifying whether the administration is needed. The information about how much to administer the drainage stimulant is information indicating the dose of the drainage stimulant, and may be information about the dose itself, or may be information for identifying the dose. The processor  30  (the processing section  40 ) determines whether or not or how much to administer the drainage stimulant based on the endoscope image and the trained model  72 . For example, the processor  30  inputs an endoscope image to the trained model  72  and determines whether or not or how much to administer the drainage stimulant based on information output from the trained model  72  about whether or not to administer the drainage stimulant or how much to administer the drainage stimulant. 
     Thus, the trained model  72  can be used estimate a state of relaxation of the lumen in the papillary portion and determine whether or not or how much to administer the drainage stimulant based on the endoscope image. This facilitates insertion of the cannula into the opening of the papillary portion in cannulating the biliary duct. 
     Here, the trained model  72  is a machine learned model built using training data and is implemented with, for example, a neural network. For example, the trained model  72  is trained with training data that is a data set in which input data are associated with ground truth data. For example, the storage device  70  stores a program describing an inference algorithm and parameters used in the inference algorithm as information of the trained model  72 . The processor  30  then performs processing based on the information of the trained model  72 . That is, the processor  30  executes the program using the parameters stored in the storage device  70  to perform the process of determining whether or not or how much to administer the drainage stimulant based on an endoscope image. For example, the inference algorithm can employ a neural network. Weight coefficients for inter-connected nodes in the neural network are the parameters. The neural network includes an input layer to which input data is fed, an intermediate layer that performs arithmetic processing on the data fed through the input layer, and an output layer that outputs recognition results based on the arithmetic processing results output from the intermediate layer. The inference algorithm is not limited to the neural network, and can employ various machine learning processing used for the recognition process. The trained model  72  is generated by a learning device. The learning device generates the trained model  72  by inputting training data, also called teacher data, into a learning model and providing feedback to the learning model based on its inference results. The training data includes a plurality of data sets, and each set includes input data and ground truth data. The ground truth data refers to the inference results that should be obtained for the input data, and is prepared in advance by, for example, medical professionals. 
     For example, the input data for the trained model  72  in the present embodiment is endoscope images from the endoscope  100 . The ground truth data for the trained model  72  is data for estimating and determining whether or not or how much to administer the drainage stimulant. For example, the ground truth data is data that indicates whether the administration of the drainage stimulant is needed or data that identifies the dose of the drainage stimulant. 
       FIG.  13    illustrates an example process of the present embodiment using the trained model  72 . In  FIG.  13   , the trained model  72  is trained with training data  74 , in which endoscope images are associated with information indicating whether or not to administer the drainage stimulant. For example, the training data  74  is created by a medical professional, such as a physician, judging a state of relaxation of the papillary portion in each of multiple training endoscope images and assigning to each endoscope image the information indicating whether or not to administer the drainage stimulant as a ground truth label. For example, the medical professional observes the image of the papillary portion in each endoscope image, judges whether it is relaxed enough to enable easy insertion of the cannula, and assigns the information indicating whether or not to administer the drainage stimulant as the ground truth label. Thus, during inference, in response to input of, for example, an endoscope image showing the papillary portion in an unrelaxed state or an endoscope image showing the papillary portion in an insufficiently relaxed state that will make it impossible to easily insert the cannula, the trained model  72  outputs information indicating that the administration of the drainage stimulant is needed. Also, during inference, in response to input of, for example, an endoscope image showing the papillary portion relaxed enough to enable easy insertion of the cannula, the trained model  72  outputs information indicating that the administration of the drainage stimulant is not needed. 
     As described above, in  FIG.  13   , the trained model  72  outputs the information indicating whether or not to administer the drainage stimulant for endoscope images showing the papillary portion, so that the processor  30  can determine whether or not to administer the drainage stimulant based on the information output from the trained model  72  and provide instructions to administer the drainage stimulant, not to administer it, or to complete the administration. For example, the processor  30  provides to an operator a notification instructing him/her to administer the drainage stimulant, not to administer it, or to complete the administration. Alternatively, in cases where the medical system  10  automatically administers the drainage stimulant, the processor  30  instructs a mechanism (spraying mechanism) that administers (sprays) the drainage stimulant to administer it, not to administer it, or to complete the administration. 
       FIG.  14    is a flowchart illustrating a process of the present embodiment when the trained model  72  in  FIG.  13    is used. First, the endoscope is inserted (step S 31 ), and the processor  30  (the processing section  40 ) acquires an endoscope image (step S 32 ). The processor  30  then inputs the endoscope image to the trained model  72  to determine whether or not to administer (spray) the drainage stimulant (step S 33 ). For example, the processor  30  determines whether or not to administer the drainage stimulant by estimating a state of relaxation of the papillary portion using the trained model  72 . If it is determined that the administration of the drainage stimulant is needed, the processor  30  instructs the administration of the drainage stimulant (step S 35 ) and moves to, for example, step S 32 . For example, the processor  30  provides a notification to the operator instructing him/her to administer the drainage stimulant, or automatically administers the drainage stimulant. On the other hand, if it is determined that the administration of the drainage stimulant is not needed, the processor  30  instructs completion of the drainage stimulant administration (step S 36 ). For example, the processor  30  provides a notification to the operator instructing him/her to complete the drainage stimulant administration, or automatically completes the drainage stimulant administration. 
       FIG.  15    explains another example process of the present embodiment using the trained model  72 . In  FIG.  15   , the trained model  72  is trained with the training data  74 , in which endoscope images are associated with drainage stimulant doses. For example, the training data  74  is created by a medical professional, such as a physician, judging a state of relaxation of the papillary portion in each of multiple training endoscope images and assigning to each endoscope image information indicating a dose of the drainage stimulant as a ground truth label. For example, the medical professional observes the image of the papillary portion in each endoscope image, determines what dose of the drainage stimulant should be administered to bring the papillary portion into a relaxed state suitable for cannulation, and assigns the information indicating the dose of the drainage stimulant as the ground truth label. Thus, in response to input of an endoscope image during inference, the trained model  72  outputs information about the dose of the drainage stimulant corresponding to that endoscope image. For example, the trained model  72  outputs information about the dose of the drainage stimulant by which the papillary portion can be brought into a suitable relaxed state. 
     As described above, in  FIG.  15   , the trained model  72  outputs the information indicating the dose of the drainage stimulant for the endoscope image showing the papillary portion, so that the processor  30  can determine the dose of the drainage stimulant based on the information output from the trained model  72  and indicate the dose of the drainage stimulant. For example, the processor  30  provides to an operator a notification indicating the dose of the drainage stimulant needed to relax the papillary portion. Alternatively, in cases where the medical system  10  automatically administers the drainage stimulant, the processor  30  indicates the dose of the drainage stimulant to a mechanism (spraying mechanism) that administers (sprays) the drainage stimulant. In  FIG.  15   , the trained model  72  also outputs information about whether or not to administer the drainage stimulant, and the processor  30  determines whether or not to administer the drainage stimulant based on this information. 
       FIG.  16    is a flowchart of a process of the present embodiment when the trained model  72  in  FIG.  15    is used.  FIG.  16    differs from  FIG.  14    in that, in step S 33  of  FIG.  16   , the processor  30  inputs an endoscope image to the trained model  72  to determine whether or not to administer (spray) the drainage stimulant and how much to administer (spray) the drainage stimulant. If it is determined in step S 34  that the administration is needed, the processor  30  instructs the administration of the drainage stimulant and indicates the dose thereof in step S 35 . If it is determined that the administration is not needed, the processor  30  instructs completion of the drainage stimulant administration in step S 36 . 
       FIG.  17    illustrates another example process of the present embodiment using the trained model  72 . The trained model  72  in  FIG.  17    is trained also using information about the drainage amount of pancreatic juice or bile, for example, trained with the training data  74  based on information about the drainage amount of pancreatic juice or bile. For example, the trained model  72  is trained to estimate a state of relaxation of the papillary portion based on the drainage amount of pancreatic juice or bile shown in the endoscope image. For example, the drainage amount of pancreatic juice or bile can be evaluated by extracting from the endoscope image color regions corresponding to pancreatic juice or bile. For example, bile can be evaluated by extracting regions of transparent dark brown, green, or intermediate colors therebetween, or regions of white turbid liquids, and pancreatic juice can be evaluated based on changes in luminance because pancreatic juice is clear and colorless. For example, when it is determined from the endoscope image that a large amount of pancreatic juice or bile is drained, the papillary portion is estimated to be sufficiently relaxed. The trained model  72  outputs information about whether or not or how much to administer the drainage stimulant based on the estimated drainage amount of pancreatic juice or bile. For example, when a small amount of pancreatic juice or bile is drained, the trained model  72  outputs information instructing administration of the drainage stimulant. When a large amount of pancreatic juice or bile is drained, the trained model  72  outputs information instructing completion of the drainage stimulant administration. Alternatively, the trained model  72  may learn a relation between the drainage amount of pancreatic juice or bile and the dose of the drainage stimulant. For example, the trained model  72  learns the dose needed to sufficiently drain the pancreatic juice or bile to bring about a relaxed state suitable for cannulation. The trained model  72  then outputs information about the dose of the drainage stimulant needed to sufficiently drain the pancreatic juice or bile to transition the current state into a relaxed state suitable for cannulation. 
       FIG.  18    illustrates another example process of the present embodiment using the trained model  72 . The trained model  72  in  FIG.  18    is trained also using information about the type of the papillary portion, for example, trained with the training data  74  based on information about the type of the papillary portion of each patient. For example, the trained model  72  learns a relation between the type of the papillary portion, the dose of the drainage stimulant needed to relax the papillary portion, and the drainage amount of pancreatic juice or bile. For example, the type of the papillary portion is from the class including common channel, separate, onion, and septal types in  FIG.  4   , or from the class including separate opening, onion, nodular, villous, flat, and vertically elongated types. For example, for patients with the papillary portion of a type that is initially relaxed to some extent, the trained model  72  is trained to determine that the papillary portion is relaxed upon detecting a small value of drainage amount of bile or pancreatic juice. On the other hand, for patients with the papillary portion of a type that is initially tight, the trained model  72  is trained to determine that the papillary portion is relaxed upon detecting a large value of drainage amount of bile or pancreatic juice. This allows the trained model  72  to output information about whether or not or how much to administer the drainage stimulant, in which individual patient differences according to the type of papillary portion are reflected. Control of endoscopic operation by electrical driving 
     As described with reference to  FIG.  21    below, the endoscope  100  employed in the present embodiment is an endoscope whose endoscopic operation is electrically driven, where the endoscopic operation is at least one of forward and backward movement of the insertion section, a curving angle of the bending section of the insertion section, or rolling rotation of the insertion section. The processor  30  positions the insertion section of the endoscope  100  with respect to the papillary portion by the electrically-driven endoscopic operation, prior to administration of the drainage stimulant. In this case, the control section  50  performs the positioning of the distal end section of the endoscope  100  by the electrically-driven endoscopic operation.  FIG.  19    is a flowchart explaining a process of the present embodiment when such electrically-driven endoscopic operation is performed. 
     First, the processor  30  (the control section  50 ; the same applies below) positions the distal end section of the endoscope  100  with respect to the papillary portion by the electrically-driven endoscopic operation (step S 40 ). For example, as shown in  FIG.  3   , the distal end section of the endoscope  100  is positioned such that the endoscope image is captured at a predetermined angle of view and in a predetermined imaging direction. For example, a reference image for positioning may be prepared, a similarity between the endoscope image and the reference image may be determined, and the distal end section of the endoscope  100  may be positioned such that the endoscope image matches the reference image as closely as possible. Details of this positioning are described below. After positioning the distal end section of the endoscope  100 , the processor  30  (the processing section  40 ) acquires an endoscope image showing the papillary portion (step S 41 ). That is, the processor  30  acquires the endoscope image via the endoscope interface  62 . Then, the processor  30  estimates a state of relaxation of the lumen in the papillary portion based on the endoscope image (step S 42 ). The processor  30  then determines whether or not or how much to administer the drainage stimulant that promotes the secretion of pancreatic juice or bile (step S 43 ). For example, as mentioned above, the processor  30  uses the trained model  72  to determine whether or not or how much to administer the drainage stimulant. 
     Thus, in  FIG.  19   , based on the endoscope image acquired after positioning the distal end section of the endoscope  100  by the electrically-driven endoscopic operation, a state of relaxation of the lumen in the papillary portion is estimated and whether or not or how much to administer the drainage stimulant is determined. Using the endoscope image positioned by electrical driving in this manner helps facilitate the process of estimating a state of relaxation based on the endoscope image and determining whether or not or how much to administer the drainage stimulant and helps improve the accuracy of this process. If, for example, endoscope images taken with various angles of view and in various imaging directions are input to the trained model  72  during the process of estimating a state of relaxation and determining whether or not or how much to administer the drainage stimulant, the accuracy of the process would decrease. In addition, in order for the trained model  72  to be able to estimate a state of relaxation and determine whether or not or how much to administer the drainage stimulant for endoscope images taken with various angles of view and in various imaging directions, a huge number of training endoscope images would be required during the training process. In this respect, in  FIG.  19   , the process of estimating a state of relaxation and determining whether or not or how much to administer the drainage stimulant is performed based on the endoscope image positioned by the electrically-driven endoscopic operation, so that the above problems can be prevented from occurring. 
     Additionally, in the present embodiment, in the case of using the endoscope  100  whose endoscopic operation, which is at least one of forward and backward movement of the insertion section, a curving angle of the bending section of the insertion section, or rolling rotation of the insertion section, is electrically driven, the processor  30  (the control section  50 ) inserts the cannula into the biliary duct by controlling the electrically-driven endoscopic operation after administration of the drainage stimulant to the papillary portion. In this case, the control section  50  controls the electrically-driven endoscopic operation during insertion of the cannula into the biliary duct.  FIG.  20    is a flowchart explaining a process of the present embodiment when such electrically-driven endoscopic operation is performed. 
     Steps S 51 , S 52 , S 53  in  FIG.  20    are similar to steps S 21 , S 22 , S 23  of  FIG.  12   , so that descriptions thereof will be omitted. It should be noted that prior to step S 51  of  FIG.  20   , the distal end section of the endoscope may be positioned by the electrically-driven endoscopic operation as in step S 40  of  FIG.  19   , and an endoscope image showing the papillary portion may be acquired after the positioning. In  FIG.  20   , after step S 53 , the processor  30  (the control section  50 ) inserts the cannula into the biliary duct by controlling the electrically-driven endoscopic operation (step S 54 ). That is, the processor  30  controls the electrically-driven endoscopic operation such that the cannula is inserted along the biliary duct by electrical driving of the endoscopic operation, which is at least one of forward and backward movement of the insertion section of the endoscope  100 , a curving angle of the bending section of the insertion section, or rolling rotation of the insertion section. 
     In this way, the cannula can be inserted into the biliary duct by controlling the electrically-driven endoscopic operation after the lumen in the papillary portion has been relaxed by the drainage stimulant. For example, without administration of the drainage stimulant, the opening of the papillary portion would be closed, making it difficult to cannulate the opening with the cannula and insert it along the biliary duct. In this regard, in the present embodiment, the secretion of pancreatic juice or bile is promoted by administration of the drainage stimulant, and after the region near the opening has been relaxed, the cannula is inserted by the electrically-driven endoscopic operation. Specifically, the cannula is inserted by the electrically-driven endoscopic operation after the papillary portion has been so relaxed that administration of the drainage stimulant will no longer be needed, or after the dose of the drainage stimulant that can sufficiently relax the papillary portion has been administered. Thus, the cannula can be more easily inserted into the opening of the papillary portion by the electrically-driven endoscopic operation. This makes it possible to properly assist inexperienced operators and the like in performing cannulation during the ERCP procedure. 
     As described with reference to  FIG.  21    below, the medical system  10  of the present embodiment includes the information processing system  20  and the endoscope  100 . The present embodiment may be implemented as a method of operating the medical system  10 . The method of operating the medical system  10  is a method of operating the medical system  10  including the endoscope  100  which captures endoscope images and whose endoscopic operation is electrically driven, where the endoscopic operation is at least one of forward and backward movement of the insertion section, a curving angle of the bending section of the insertion section, or rolling rotation of the insertion section. The operating method includes a step of positioning the insertion section with respect to the papillary portion of the duodenum by electrically-driven endoscopic operation, and a step of estimating a state of relaxation of the lumen in the papillary portion based on an endoscope image from the endoscope  100  whose insertion section has been positioned and determining whether or not or how much to administer the drainage stimulant that promotes the secretion of pancreatic juice or bile. 
     Medical System 
     A medical system of the present embodiment is now described. When cannulation into the biliary duct is performed, it is performed by referring to an endoscope image showing the papillary portion. As described with reference to  FIGS.  3  and  4   , there are various forms of papillary portion and luminal tissue, and it is difficult to specify the insertion position and insertion direction of the cannula from the endoscope image. 
     On the other hand, the operator estimates the position of the opening and the travelling direction of the biliary duct based on past cases, experiences, and the like while viewing the endoscope image, and tries to insert the cannula from the opening into the biliary duct according to the estimation. At this time, in order to more accurately estimate the position of the opening and the travelling direction of the biliary duct, it is desirable that the position of the papillary portion in the image and the angle of view of the image are easy to compare with those in the past cases or are familiar to the operator. 
     As shown in  FIG.  1   , such positioning of the endoscope is performed by operating the distal end of the endoscope insertion section reaching the duodenum from outside the body. However, since the insertion section and the organ through which the insertion section passes are flexible, the operation performed at the base end of the insertion section is not easily transmitted to the distal end section. In addition, since the distal end section of the endoscope is not fixed to the duodenum and floats in the air, the distal end section of the endoscope is not stable with respect to the papillary portion, and the positional relationship between the distal end section and the papillary portion is not easily determined. For these reasons, it is difficult to adjust the position of the distal end section of the endoscope so that the field of view of the endoscope is facing directly front of the papillary portion or so that the papillary portion appears in the center of the field of view. 
     Therefore, in the present embodiment, the above-described positioning is automated by an electric medical system to assist the ERCP procedure. Further, by adding a configuration in which the insertion section of the endoscope is held in the duodenum, the electrically-driven force can be easily transmitted to the distal end section of the endoscope and the position of the distal end section can be desirably controlled. The details of this structure are described below. 
       FIG.  21    shows a configuration example of a medical system  10  according to the present embodiment. The medical system  10  includes an endoscope  100  and a control device  600 . Further, the medical system  10  may include an overtube  710 , a balloon  720 , and a treatment tool  400 . The medical system  10  is also referred to as an endoscope system or an electric endoscope system. The information processing system  20  described with reference to  FIG.  11    can be implemented by, for example, the hardware of the control device  600  in  FIG.  21   . Thus, the medical system  10  of the present embodiment includes the information processing system  20  implemented by the control device  600  and the endoscope  100 . 
     The overtube  710  is a tube with a variable hardness that covers the insertion section  110  of the endoscope  100 . The balloon  720  is provided near the distal end on the outer side of the overtube  710 . When the endoscope  100  and the overtube  710  are inserted into the body, at least the bending section of the insertion section  110  is exposed from the distal end of the overtube  710 . The bending section refers to a section structured to be bent at an angle corresponding to the curving operation in the vicinity of the distal end of the insertion section  110 . The base end of the overtube  710  is present outside the body. The base end side of the insertion section  110  is exposed from the base end of the overtube  710 . 
     An insertion opening  190  of the treatment tool is provided at the base end side of the insertion section  110 , and a treatment tool channel for allowing the treatment tool  400  to pass through from the insertion opening  190  to the opening of the distal end section  130  is provided inside the insertion section  110 . The insertion opening  190  of the treatment tool is also called a forceps opening; however, the treatment tool to be used is not limited to forceps. 
     The endoscope  100  is detachably connected to a control device  600  using connectors  201  and  202 . The control device  600  includes a drive control device  200  to which the connector  201  is connected, and a video control device  500  to which the connector  202  is connected. The drive control device  200  controls the electrical driving of the endoscope  100  via the connector  201 . Although not shown in  FIG.  21   , an operation device for manually operating the electrical driving may be connected to the drive control device  200 . The video control device  500  receives an image signal from a camera provided at the distal end section  130  of the endoscope  100  via the connector  202 , generates a display image from the image signal, and displays it on a display device (not shown). In  FIG.  21   , the drive control device  200  and the video control device  500  are shown as separate devices, but they may be structured as a single device. In this case, the connectors  201  and  202  may be integrated into a single connector. 
       FIG.  22    is a flowchart of the procedure in the present embodiment. Here, an electric endoscope is assumed in which the forward and backward movement of the insertion section  110  of the endoscope  100 , the curving of the bending section of the insertion section  110 , and the rolling rotation of the insertion section  110  are electrically driven. However, it is sufficient that at least one of these functions is electrically driven. The term “electrical driving” means that the endoscope is driven by a motor or the like based on an electrical signal for controlling the endoscopic operation. For example, when the electrical driving is manually operated, an operation input to the operation device is converted into an electrical signal, and the endoscope is driven based on the electrical signal. In the following, the forward and backward movement may be simply referred to as “forward/backward movement”. 
     In step S 1 , the operator inserts the insertion section  110  of the endoscope  100  and the overtube  710  into the duodenum. More specifically, in a state where the insertion section  110  is inserted into the overtube  710 , the insertion section  110  and the overtube  710  are inserted into the duodenum together. The overtube  710 , which is changeable in hardness, is soft in step S 1 . For example, the operator can move the insertion section  110  and the overtube  710  forward by a non-electrically-driven manual operation so that they are inserted into the body. The non-electrical driving means that the endoscope  100  is not electrically driven by a motor or the like, instead, the force applied to the operation section is directly transmitted to the endoscope by a wire or the like, thereby operating the endoscope. For example, in the present embodiment, steps S 1  to S 4  are not electrically driven. In this case, it is sufficient that at least the forward/backward movement is not electrically driven, and the curving, the rolling rotation, or both may be manually operated by electrical driving. 
     In step S 2 , the operator inserts the insertion section  110  until the distal end section  130  reaches the vicinity of the papillary portion. For example, when the operator manually inserts the insertion section  110  by non-electrical driving, the operator inserts the insertion section  110  until the papillary portion becomes visible in the endoscope image. At this point, the distal end of the endoscope  100  does not need to accurately reach the papillary portion; the distal end of the endoscope  100  may reach a position before the papillary portion or past the papillary portion. 
     In step S 3 , the operator fixes the distal end of the overtube  710  to the duodenum. As an example, the operator performs an operation to inflate the balloon  720  provided near the distal end of the overtube  710 , and fixes the distal end of the overtube  710  to the duodenum by the balloon  720 . In step S 4 , the operator performs an operation to harden the overtube  710 . At this time, the overtube  710  is hardened while maintaining its shape in a state immediately before hardening, that is, the shape when it is inserted from the mouth to the duodenum. As a result, the insertion section  110  is held by the hardened overtube  710  and the balloon  720 , thereby fixing the insertion route of the insertion section  110 . These steps S 3  and S 4  are referred to as first positioning. 
     In step S 5 , the endoscope  100  is connected to the motor unit, and the non-electrical driving is switched to the electrical driving. The method of switching between the non-electrical driving and the electrical driving varies depending on the configuration of the drive mechanism. For example, in steps S 1  to S 4 , the forward/backward movement may be non-electrically driven and the curving and the rolling rotation may be electrically driven. In this case, the forward/backward movement may be switched from the non-electrical driving to the electrical driving by connecting the endoscope  100  to the forward/backward drive device (not shown). Further, when the curving operation by non-electrical driving is enabled by providing a curving operation dial or the like capable of non-electrically performing the curving operation, the curving movement may be switched from the non-electrical driving to the electrical driving, for example, by connecting the connector  201  to the drive control device  200 . Alternatively, even if the motor unit is kept connected, the motor may be structured to be detachable by a clutch mechanism or the like, and the non-electrical driving may be switched to the electrical driving by the clutch mechanism. Step S 5  may be performed before step S 1 . For example, when the forward/backward movement is manually operated by electrical driving, the endoscope  100  may be connected to the motor unit before step S 1 . 
     In step S 6 , the drive control device  200  automatically positions the distal end section  130  at the papillary portion, and the operator confirms that the position of the distal end section  130  has been adjusted so that the papillary portion is captured at a predetermined position on the endoscope image. The drive control device  200  acquires an endoscope image from the video control device  500  and performs positioning of the distal end section  130  of the endoscope  100  based on the endoscope image. More specifically, the drive control device  200  controls the forward/backward movement, curving, or rolling rotation by electrical driving so that the papillary portion is captured at a position registered in advance on the endoscope image. The position registered in advance is, for example, the center of the image. The positioning may be performed so that the opening of the luminal tissue is captured at a position registered in advance. Further, the drive control device  200  may perform electrical driving control based on the endoscope image so that the camera directly faces the front of the papillary portion or so that the papillary portion is captured at an appropriate angle of view. The drive control device  200  may also adjust the angle of view in imaging the papillary portion by controlling the diameter of the balloon  720  by electrical driving based on the endoscope image so that the distance between the camera and the papillary portion can be changed without changing the line-of-sight direction of the camera. This step S 6  is referred to as second positioning. 
     In step S 7 , the operator inserts a cannula into the treatment tool channel through the insertion opening  190  to start cannulation into the biliary duct. 
     In  FIG.  22   , although the operation of the balloon in step S 3  and the hardening of the overtube in step S 4  are performed by non-electrical driving, they may be performed by electrical driving. In this case, the operator inputs an instruction from the operation device, and the drive control device  200  may inflate the balloon or harden the overtube by electrical driving using the instruction as a trigger. Alternatively, the drive control device  200  may perform an image recognition process for detecting the papillary portion from the endoscope image, and may automatically inflate the balloon or harden the overtube using the detection of the papillary portion from the endoscope image as a trigger. 
     According to the procedure flow described above, by inflating the balloon  720  before hardening the overtube  710  in step S 3 , the position of the distal end of the overtube  710  does not shift when the overtube  710  is hardened. Specifically, the distal end of the overtube  710  can be accurately positioned. In addition, by the first positioning in steps S 3  and S 4 , the insertion route of the insertion section  110  is held by the balloon  720  and the overtube  710 . As a result, in the second positioning in step S 6 , the forward/backward movement, curving, or rolling rotation of the endoscope  100  due to the electrical driving is easily transmitted from the base end side to the distal end of the insertion section  110 . 
       FIG.  23    shows the vicinity of the distal end of an endoscope positioned by the overtube  710  and the balloon  720 . As shown in  FIG.  23   , the balloon  720  is fixed at a position slightly apart from the papillary portion to the pyloric side of the stomach. More specifically, the balloon  720  is positioned closer to the base end of the insertion section  110  than the base end of the bending section of the insertion section  110 . By combining such a balloon  720  with the overtube  710  having a variable hardness, the bending section exposed to the papillary portion side from the balloon  720  and the distal end section  130  can be freely operated without being fixed, and the electrical driving from the base end side can be efficiently transmitted to the distal end section  130  of the endoscope. 
     The endoscopic operation by the electrical driving is the forward and backward movement shown in A 1 , a curving movement shown in A 2 , or a rolling rotation shown in A 3 . The forward movement is a shift toward the distal end side along the axial direction of the insertion section  110 , and the backward movement is a shift toward the base end side along the axial direction of the insertion section  110 . The curving movement is a movement by which the angle of the distal end section  130  is changed due to the bending of the bending section. The curving movement includes curving movements in two orthogonal directions, which can be controlled independently. One of the two orthogonal directions is referred to as the vertical direction and the other is referred to as the horizontal direction. The rolling rotation is a rotation about an axis of the insertion section  110 . 
       FIG.  23    shows an example in which the balloon  720  is attached to the distal end of the overtube  710  and the endoscope protrudes from the distal end of the overtube  710 . However, it is sufficient that the overtube  710  and the balloon  720  are configured so that a portion of the bending section beyond the base end can freely move. For example, it may also be arranged such that a soft tube with a constant hardness extends beyond the overtube with a variable hardness, and the balloon  720  is attached to the boundary thereof. In this case, although a part of the base end side of the bending section is covered with the soft tube, its movement is not hindered. 
       FIG.  24    is a schematic view of an endoscope  100  including a bending section  102  and a driving mechanism thereof. An endoscope  100  includes a bending section  102 , a soft section  104 , and a connector  201 . 
     The bending section  102  and the soft section  104  are covered with an outer sheath  111 . The bending section  102  includes a plurality of curving pieces  112  and a distal end section  130  connected to the distal end of the curving pieces  112 . Each of the plurality of curving pieces  112  and the distal end section  130  is connected in series from the base end side to the distal end side by a rotatable connecting section  114 , thereby forming a multi joint structure. The connector  201  is provided with a coupling mechanism  162  on the endoscope side connected to a coupling mechanism on the drive control device  200  side. By attaching the connector  201  to the drive control device  200 , it is possible to electrically drive the curving movement. A curving wire  160  is provided in the outer sheath  111 . One end of the curving wire  160  is connected to the distal end section  130 . The curving wire  160  passes through the soft section  104  by penetrating through a plurality of curving pieces  112 , turns back in a coupling mechanism  162 , passes through the soft section  104  again, penetrates through the plurality of curving pieces  112 . The other end of the curving wire  160  is connected to the distal end section  130 . The driving force from the wire drive section of the drive control device  200  is transmitted to the curving wire  160  via the coupling mechanism  162  as the pulling force of the curving wire  160 . 
     As shown by the solid line arrow B 2  in  FIG.  24   , when the upper wire in the figure is pulled, the lower wire is pushed, whereby the multiple joints of the curving pieces  112  are bent upward in the figure. As a result, as indicated by the solid line arrow A 2 , the bending section  102  is curved upward in the figure. When the lower wire in the figure is pulled as indicated by the dotted arrow B 2 , similarly, the bending section  102  is curved downward in the figure as indicated by the dotted arrow A 2 . As described with reference to  FIG.  23   , the bending section  102  can be curved independently in two orthogonal directions. Although  FIG.  24    shows a curving mechanism for one direction, two sets of curving wires are actually provided, and each curving wire can be curved independently in two directions by being pulled independently by the coupling mechanism  162 . 
     Note that the mechanism for the electrically-driven curving is not limited to that described above. For example, a motor unit may be provided instead of the coupling mechanism  162 . Specifically, it may be arranged such that the drive control device  200  transmits a control signal to the motor unit via the connector  201 , and the motor unit drives the curving movement by pulling or relaxing the curving wire  160  based on the control signal. 
       FIG.  25    shows a detailed configuration example of a forward/backward drive device  800 . The forward/backward drive device  800  includes a motor unit  816 , a base  818 , and a slider  819 . 
     As shown in the upper and middle figures, the extracorporeal soft section  140  of the endoscope  100  is provided with an attachment  802  detachable from the motor unit  816 . As shown in the middle figure, the attachment of the attachment  802  to the motor unit  816  enables electrical driving of forward/backward movement. As shown in the lower figure, the slider  819  supports the motor unit  816  while enabling the motor unit  816  to move linearly with respect to the base  818 . The slider  819  is fixed to an operating table. As shown in B 1 , the drive control device  200  transmits a forward or backward control signal to the motor unit  816  by wireless communication, and the motor unit  816  and the attachment  802  move linearly on the slider  819  based on the control signal. As a result, the forward and backward movement of the endoscope  100  shown in A 1  in  FIG.  23    is achieved. Note that the drive control device  200  and the motor unit  816  may be connected by wired connection. 
       FIG.  26    is a perspective view of the connecting section  125  including a rolling drive device  850 . The connecting section  125  includes a connecting section main body  124  and a rolling drive device  850 . 
     The insertion opening  190  of the treatment tool is provided in the connecting section main body  124  and is connected to the treatment tool channel inside the connecting section main body  124 . The connecting section main body  124  has a cylindrical shape, and a cylindrical member coaxial with the cylinder is rotatably provided inside the connecting section main body  124 . The base end section of the intracorporeal soft section  119  is fixed to the outside of the cylindrical member, and the base end section serves as a rolling operation section  121 . As a result, the intracorporeal soft section  119  and the cylindrical member can rotate with respect to the connecting section main body  124  about the axial direction of the intracorporeal soft section  119 . The rolling drive device  850  is a motor unit provided inside the connecting section main body  124 . As shown in B 3 , the drive control device  200  transmits a rolling rotation control signal to the rolling drive device  850  by wireless communication, and the rolling drive device  850  rotates the base end section of the intracorporeal soft section  119  with respect to the connecting section main body  124  based on the control signal, thereby causing rolling rotation of the intracorporeal soft section  119 . As a result, the rolling rotation of the endoscope  100  shown in A 3  in  FIG.  23    is achieved. The rolling drive device  850  may include a clutch mechanism, and the rolling rotation may be switched between non-electrical driving and electrical driving by the clutch mechanism. The drive control device  200  and the rolling drive device  850  may be connected by wired connection via a signal line passing through the internal route  101 . 
       FIG.  27    shows a detailed configuration example of a distal end section  130  of an endoscope including a raising base of a treatment tool. The upper figure shows an external view of the distal end section  130 . An opening  131  of a treatment tool channel, a camera  132 , and an illumination lens  133  are provided on the side surface of the distal end section  130 . As shown in the lower figure, the direction parallel to the axial direction of the distal end section  130  is defined as z direction, the direction parallel to the line-of-sight direction of the camera  132  is defined as y direction, and the direction orthogonal to the z direction and they direction is defined as x direction. The lower figure shows a cross-sectional view of the distal end section  130  in a plane that is parallel to the yz plane of the treatment tool channel and that passes through the opening  131  of the treatment tool channel. 
     The distal end section  130  includes a raising base  134  and a raising base wire  135 . The raising base  134  is swingable about an axis parallel to the x direction. One end of the raising base wire  135  is connected to the raising base  134 , while the other end is connected to the drive control device  200  via the connector  201 . As shown in B 4 , the wire drive section of the drive control device  200  pushes and pulls the raising base wire  135  to swing the raising base  134 , thereby, as shown in A 4 , changing the raising angle of the treatment tool  400 . The raising angle is an angle of the treatment tool  400  protruding from the opening  131 . The raising angle can be defined, for example, by an angle formed by the treatment tool  400  protruding from the opening  131  and the z direction. 
     Although the embodiments to which the present disclosure is applied and the modifications thereof have been described above, the present disclosure is not limited to the embodiments and the modifications thereof, and various modifications and variations in elements may be made in implementation without departing from the spirit and scope of the present disclosure. The plurality of elements disclosed in the embodiments and the modifications described above may be combined as appropriate to form various disclosures. For example, some of all the elements described in the embodiments and the modifications may be deleted. Furthermore, elements in different embodiments and modifications may be combined as appropriate. Thus, various modifications and applications can be made without departing from the spirit and scope of the present disclosure. Any term (the processor) cited with a different term (the processing section or the control section) having a broader meaning or the same meaning at least once in the specification and the drawings can be replaced by the different term in any place in the specification and the drawings.