Abstract:
Systems and methods are provided for controlling lateral movement of a medical capsule system. A capsule housing is configured to be inserted into an anatomical structure of a patient. The multichannel tether is coupled to a rear of the capsule and includes at least one liquid exhaust channel conveying liquid to the capsule housing. The plurality of liquid exhaust ports are positioned around an outer circumference of the capsule housing and each configured to controllably expel liquid laterally from the capsule housing at varying rates to affect lateral movement of the capsule housing.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/048,105, filed Sep. 9, 2015, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Gastric cancer is the second leading cause of cancer death worldwide. Screening programs have had a significant impact on mortality in settings such as Japan. Nearly 70% of cases occur in low/middle income countries (LMICs), where endoscopy resources are traditionally limited. The present invention relates to endoscopic systems and methods and, more specifically, to endoscopic screening mechanisms. 
       SUMMARY 
       [0003]    Esophagogastroduodenoscopy (EGD) is a procedure used in the detection of esophageal and stomach cancers. Currently flexible endoscopes are used in EGD to view the esophagus and stomach; however, flexible endoscopes are both expensive and require large additional machinery to disinfect the system once used. 
         [0004]    In many parts of the developing world, instances of stomach cancer are steadily rising and access to flexible endoscopes by the general population is minimal due the aforementioned costs and inability to reliably disinfect systems. The Hydro-Jet Endoscopic Capsule (HEC) described herein has a low fabrication cost and can be disposed of after each use, it overcomes the challenges created by flexible endoscope systems. This creates an affordable alternative for endoscopy in large markets such as East Asia, Central America, South America and Eastern Europe. 
         [0005]    Currently there are no low cost alternatives to standard endoscopies. This limits the availability of the procedure in the developing world such as East Asia, Central America, South America and Eastern Europe, where esophageal and stomach cancers are rising within the population. The HEC is a novel medical device, firstly, in the fact that it uses an accessible, biocompatible renewable resource (water) for control and maneuverability. Second, the HEC&#39;s low manufacturing cost and disposable design allow it to be used without the additional acquisition of expensive sterilization equipment. Lastly, the HEC system&#39;s low initial costs allow it to be an affordable system in developing healthcare markets. 
         [0006]    In some embodiments, the invention allows for Esophagogastroduodenoscopy (EGD) procedures to be accomplished at low costs and without sterilization/cleaning/processing equipment using a Hydro-Jet Endoscopic Capsule (HEC). This novel approach bypasses the typical expenses of traditional endoscopes which are both expensive to purchase and require additional machinery to clean for reuse. 
         [0007]    The HEC is maneuvered within the body using streams of water that are ejected out of the main body of the capsule at particular angles and at particular pressures. A multi-channel soft tether provides high-pressurized water from a water distribution system to a set of intake nozzles on the capsule. Operated by the user using a computer user interface, the water distribution system controls the flow rate of water into each exit channel on the capsule. The HEC&#39;s core is capable of carrying a Video Processing Unit (VPU) that relays real-time images during the procedure for both control and diagnosis. The VPU is reusable between procedures without sterilization/cleaning to reduce the overall procedure cost. The HEC itself is also reconfigurable to host existing on-the-market endoscopic cameras and can be setup to use a disposable camera if need arises. 
         [0008]    Once an EGD procedure is complete, the VPU is removed from the HEC. The HEC and its multi-channel soft tether are disposed. The VPU is then inserted into a new HEC with multi-channel soft tether for use in the next patient. Various constructions of the systems and methods described herein provide a novel, ultra low-cost (&lt;1-2 USD per case), disposable system for gastric cancer screening for use in resource-limited settings, including rural villages. 
         [0009]    In one embodiment, the system includes a 10×26 mm capsule (fabricated from a biocompatible plastic material) with an attached multi-channel soft tether (diameter 5 mm) that provides high-pressure water to four articulated water-jet nozzles in the capsule. A miniature camera with LEDs is placed at the front of the capsule, with cable located in a fifth tether channel. The tether is connected to a water distribution system, which is used to control the flow of water through each channel in the capsule, thus propelling the capsule. The capsule is controlled by an external joystick. The video processing unit presents the camera view on a dedicated monitor. The capsule and soft tether are designed to be disposable and ultra-low cost (unit price &lt;1-2 USD). The endoscopic camera is the only reusable component, fitted with an efficient engagement/disengagement mechanism. Once inside the capsule, the camera is sealed from the external environment and without need for reprocessing after use. 
         [0010]    The system was tested for its ability to allow for visualization of key gastric landmarks in a freshly excised stomach from a 40 Kg Yorkshire swine. The landmarks (pylorus, antrum, greater and lesser curvatures, fundus, and cardia) were labeled using a series of laser lights placed external to the stomach and were visible from within the stomach. Six trials were performed by a single endoscopist. Time and identification of the laser labeled landmarks were recorded. 
         [0011]    All landmarks were adequately visualized using the system in all trials. The total time for each trial was 6 min 15 sec±1 min 51 sec. All locations were appropriately identified by the endoscopist. A total of 1.35 L±0.4 L of water was utilized for each trial. There was no evidence of gastric perforation or trauma to the porcine model after each trial. The system allowed for visualization of landmarks in a porcine stomach in a safe and efficient manner. This ultra low-cost endoscopy would allow for gastric cancer screening in low resource settings where there is a high incidence of gastric cancer. In vivo porcine survival studies are ongoing. 
         [0012]    In another embodiment, the invention provides a medical capsule system including a capsule housing, a multichannel tether, and a plurality of liquid exhaust ports positioned around an outer circumferences of the capsule housing. The capsule housing is configured to be inserted into an anatomical structure of a patient. The multichannel tether is coupled to a rear of the capsule and includes at least one liquid exhaust channel conveying liquid to the capsule housing. The plurality of liquid exhaust ports are each configured to controllably expel liquid at varying rates to affect lateral movement of the capsule housing. 
         [0013]    In yet another embodiment, the invention provides a method of performing esophagogastroduodenoscopy using a hydrojet medical capsule system. The medical capsule system includes a capsule housing, a multichannel tether coupled to the rear of the capsule housing, and a plurality of liquid exhaust ports positioned around an outer circumference of the capsule housing to controllably expel liquid at varying rates. The capsule housing is inserted into the patient&#39;s esophagus through the mouth and linearly advanced to the stomach of the patient. Water is provided to the capsule through at least one liquid exhaust channel positioned within the multichannel tether and controllably expelled through one of the plurality of exhaust ports to affect lateral movement of the capsule. 
         [0014]    Some embodiments of the invention also provide for detection of tissue damage, esophageal and stomach cancer, and other abnormalities in esophageal and stomach organs. 
         [0015]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic view of a hydrojet capsule according to one embodiment inserted through the mouth of a patient and maneuvered into the stomach. 
           [0017]      FIG. 2A  is an exploded view of the hydrojet capsule of  FIG. 1 . 
           [0018]      FIG. 2B  is a partial cross-sectional view of the main outer shell body of the hydrojet capsule of  FIG. 2A . 
           [0019]      FIG. 3  is another schematic view of the hydrojet capsule of  FIG. 1  being maneuvered through the stomach of a patient. 
           [0020]      FIG. 4  is a block diagram of a control system for the hydrojet capsule of  FIG. 1 . 
           [0021]      FIG. 5  is a schematic diagram of a hydrojet capsule with a modular tool system. 
           [0022]      FIG. 6  is a schematic diagram of a hydrojet capsule with a permanently affixed camera system. 
           [0023]      FIG. 7  is a schematic diagram of a disposable hydrojet capsule with a permanently affixed camera system. 
           [0024]      FIG. 8  is a schematic diagram of a pressurized water supply and control system for a hydrojet capsule. 
           [0025]      FIG. 9  is a cross-sectional view of a pinch valve for controlling water flow to the hydrojet capsule in the pressurized water supply and control system of  FIG. 8 . 
           [0026]      FIG. 10  is a cross-sectional view of a hydrojet for expelling water from a fluid supply line through an exhaust port of a hydrojet capsule. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
         [0028]      FIG. 1  illustrates an example of a system and method for performing esophagogastroduodenoscopy (EGD) using a hydrojet endoscopic capsule (HEC)  100 . The HEC  100  is maneuvered within the body of a patient  101  using fluidic jets that expel a fluid (typically potable water) out of the main body  103  of the capsule  100 . A multi-channel soft tether  105  provides pressurized fluid from a fluid distribution system (described in further detail below) to a set of nozzles on the capsule in order to control the thrust produced by the nozzles. In the example of  FIG. 1 , the capsule  100  is equipped with a camera  107  and one or more LEDs  109  for illuminating and capturing images of the interior anatomy of the patient  101 . 
         [0029]    The main body  103  of the capsule  100  includes a plurality of exhaust ports  111  through which the pressurized fluid medium is expelled to control the full hemispherical movement of the capsule within a workspace. One or more suction ports  113  are also positioned on the main body  103  of the capsule  100  and are used to extract fluid from the patient&#39;s internal anatomy (e.g., the patient&#39;s stomach and/or GI tract) in order to prevent over inflation of the anatomy by the fluid that is injected for maneuvering the capsule  100 . 
         [0030]    In some embodiments, the capsule  100  is equipped with other sensors including, for example, an inertial sensor. The inertial sensor (e.g., an accelerometer) supplements manual control signals provided by a user and is used to implement closed loop control of the capsule system as described in further detail below. 
         [0031]    In the example of  FIG. 1 , the capsule  100  is inserted through the mouth of the patient  101  and extended through the cardia  115  into the stomach. In the stomach, the jets of the capsule  100  controllably expel fluid through the exhaust ports  111  to maneuver the capsule along the fundus  117 , the lesser curvature  119 , and the greater curvature  121  towards the pylorus  123 . 
         [0032]      FIG. 2A  illustrates the capsule  100  in further detail. In the example of  FIG. 2A , the main body  103  of the capsule  100  is selectively openable to provide access to a sealed compartment inside the capsule  100 . In this example, the main body  103  is opened by detaching an outer shell front cap  203  from the outer shell main body  201 . An inner core  205  is positioned inside the main body  103  to provide structural support and to aid in placement of internal components of the capsule  100 . The camera  107  extends linearly from the distal end of the inner core  205  and the LEDs  109  are mounted on the distal end of the inner core  205 . 
         [0033]    The exhaust ports  111  and suction ports  113  of the capsule  100  are formed in the outer shell main body  201  of the capsule  100  in this example. As shown in  FIG. 2B , four exhaust ports  111  are positioned around the circumference of the main body  103  at 90 degree angles relative to each other. However, it is noted that other quantities and spacings of exhaust ports are possible—for example, a total of three exhaust ports may be positioned around the circumference of the main body at 120 degree angles relative to each other. 
         [0034]    Returning to the example of  FIGS. 2A and 2B , a pair of suction ports  113  is positioned on opposite sides of the main body  103  at a 45 degree angle relative to the respective neighboring exhaust ports  111 . In this example, the exhaust ports  111  are positioned to provide for lateral maneuverability of the capsule  100 . For example, to move the capsule  100  to the right, water is controllably expelled from the exhaust port  111  on the left of the capsule main body  103 . To dampen the movement of the capsule  100 , water may simultaneously be expelled from the exhaust port  111  on the right side of the capsule main body  103  at a lesser flow rate to counteract the thrust produced by the left-side jet. Similarly, to move the capsule  100  laterally upward, water is controllably expelled at a greater flow rate from the exhaust port  111  on the bottom of the capsule main body  103 . Furthermore, in some construction, the suction ports are also controllably operated to aid in the lateral movement of the capsule  100  by drawing water to pull the capsule in a particular direction. 
         [0035]    For example, referring to  FIG. 3 , once the capsule  100  is inserted through the cardia  115  of the stomach (at position  301 ), the capsule may be turned towards the fundus  117  by expelled fluid through the left-side exhaust port (relative to the reader in  FIG. 3 ). This left-side expulsion will cause the capsule  100  to move along the greater curvature  121  of the stomach towards the fundus  117  (position  303 ). Conversely, controllably expelling water at a greater pressure through the right-side exhaust port causes the capsule  100  to move to the left (position  305 ). Continued right-side expulsion combined with continued linear insertion of the capsule  100  causes the capsule  100  to move along the greater curvature  121 , crossing the pylorus  123  until it reaches a target position along the lesser curvature  119  (position  307 ). 
         [0036]    As shown in  FIG. 3 , the capsule  100  has an initial range of motion that can be provided by expelling fluid within the contents of the stomach. However, the range of motion can be extended by contacting the mucosa (e.g., at position  305 ) and then expelling fluid against the mucosa to generate thrust of the capsule  100 . 
         [0037]    In some embodiments, linear movement of the capsule  100  is achieved by pushing the flexible tether  105  further into the esophagus of the patient to advance the linear position of the capsule and by pulling the flexible tether to retract the position of the capsule  100 . However, in other embodiments, the jets used to expel fluid through the exhaust ports  111  of the capsule  100  are angled towards the rear of the capsule to provide forward and lateral thrust. Similarly, the suction ports  113  can be angles towards the front of the capsule  100  to assist in forward movement of the capsule by drawing water from in front of the capsule  100  to pull the capsule  100  forward. 
         [0038]    Furthermore, in addition to controllably expelling fluid through the exhaust ports to cause the capsule to move laterally, the rate at which fluid is expelled can be controlled to stabilize the capsule in a current position. 
         [0039]      FIG. 4  illustrates an example of a control system for operating and maneuvering the capsule  100 . A pump  401  draws fluid from a water source  403  (e.g., a fluid supply tank/reservoir) and provides pressuring water to a fluid manifold  405 . A series of controllable valves  407  (either proportional or on/off valves) direct the flow of the pressurized fluid through a series of fluid supply lines  409  to the capsule  100 . Each valve  407  and corresponding supply line  409  provides fluid that is expelled through one or more specific exhaust ports  111  on the capsule body. Therefore, the lateral movement of the capsule  100  is controlled by operating the valves  407 . 
         [0040]    A computer  411  is used to control lateral movement of the capsule by generating output signals to valve controller circuitry  413 , which controls the operation of the individual valves  407 . The computer  411  may control the valves in response to signals from on-board sensors of the capsule (such as, for example, the accelerometer discussed above). The computer  411  may also interface with one or more user controls (not pictured) through which an operator can guide the movement of the capsule  100 . These user controls may include, for example, one or more foot pedals, a joy stick, or other user interface control device. The computer also provides control signals  415  directly to the capsule  100  for operating on-capsule devices such as, for example, the LEDs and the video camera system and also receives data signals  417  from the capsule (e.g., video data from the camera). In some embodiments, the camera data received from the capsule through line  417  is displayed to the user on the computer  411  to aid in the maneuvering and navigation of the capsule  100 . The electronic lines  415  and  417  and the fluid supply lines  409  are grouped together and housing within the multi-channel flexible tether of the capsule  100 . 
         [0041]      FIGS. 5, 6, and 7  further illustrate various examples of the hydrojet capsule  100 . The example of  FIG. 5  provides a modular capsule that can be selectively fitted with a variety of different tools. Alternatively (or in addition), the capsule system of  FIG. 5  can provide a low-cost disposable housing with reusable, more expensive components that are selectively connected to the capsule system and sealed within an internal compartment of the capsule. The example of  FIG. 5  includes a selectively operable capsule body  501  with an attached multi-channel tether that provides a plurality of water intake lines  503  and one or more electronic data/power lines  505 . Exhaust ports  507   a  and  507   b  are positioned around the capsule body. A modular tool  509  is placed within the sealed main body  501  of the capsule. In this example, the modular tool  509  is a video camera system and, as such, the main body  501  is equipped with a lens  511  to enable the video camera system to capture images. The capsule body  501  also includes an electrical connector coupling  513  to connect the modular tool  509  to the electrical data/power line  505 . 
         [0042]    In reusable modular systems, the camera  509  can be removed and replaced with a different tool/system. However, in disposable systems, the capsule body  501  and the flexible tether are constructed of low-cost materials and are disposed after use. As such, sanitization of the capsule body  501  is not necessary. Furthermore, because the more expensive video camera system  509  is sealed within a compartment of the capsule body  501 , the camera system  509  can be reused by coupling the camera system  509  into another capsule body  501  without requiring additional sanitization of the camera system  509 . 
         [0043]    In the example of  FIG. 6 , provides another implementation with reusable component that must be sanitized between each use. The main body  601  is coupled to a plurality of fluid supply lines  603  and one or more electrical data/power lines  605 . The main body also includes a plurality of exhaust ports  607   a,    607   b  positioned around the capsule body  601  for maneuvering the capsule. However, in this example, the capsule body  601  includes a permanently affixed video camera system  609 . Because the video camera system  609  is permanently affixed, the capsule body  601  and the video camera system  609  must be properly sanitized before being reused. 
         [0044]      FIG. 7  provides a further example in which a low-cost, permanently affixed camera is included in the capsule system. By using a low-cost camera, the resolution and image quality is reduced. However, the camera system and the capsule can be disposed after use; thereby negating the need for sanitization procedures which can be difficult in some environments/locations. The capsule system of  FIG. 7  also includes a disposable main body  701  coupled to a flexible tether that provides a plurality of fluid supply lines  703  and one or more electrical data/power lines  705 . The capsule body  701  includes a plurality of exhaust ports  707   a,    707   b  for controlling lateral movement of the capsule and the permanently affixed, low-cost, disposable camera system  709 . 
         [0045]    As discussed above, the capsule system receives pressurized fluid from an external system to control lateral movement of the capsule. In the example of  FIG. 4 , water is drawn from a reservoir/tank  403  by a pump  401 . However, other pressurized fluid supply/control mechanisms are possible.  FIG. 8  illustrates an example of a fluid distribution system  800  that controllably provides pressurized fluid to each nozzle of the capsule to produce thrust for the capsule. A fluid tank  801  holds water in a pressurized/sealed vessel. An air supply  803  provides pressurized gas/air that is provided to the fluid tank  801  above the held water. The air supply  803  can include, for example, an electrically powered pneumatic pump or a regulated tank of pressurized air. The increased air pressure within the fluid tank  801  applies pressure to the water stored therein and pushes the water into the plurality of supply lines  805 . Each supply line is equipped with a controllable pinch valve  807  to regulate the amount of water that passes through each supply line  805  to the capsule  809  and to regulate the flow rate in each supply line  805 . 
         [0046]    In systems that use a regulated compressed air tank as the air supply  803 , the system can have very low power consumption requirements because no electric pump is needed to supply fluid to the capsule. Instead, the compressed gas, which can be carried in portable canisters, is used in conjunction with the dispensing pressure vessel to control maneuvering of the capsule. Because the system does not require electric power to drive a fluid or pneumatic pump, the need for external infrastructure during use is nearly eliminated, making the system more portable and potentially battery powered. These features make the system particularly appealing for use in developing countries and rural areas. 
         [0047]    In some embodiments, the fluid distribution system  800  also includes a weight sensor that monitors the weight of the fluid tank  801  in real-time. This weight measurement is then used by the computer control system (e.g., computer  411  in  FIG. 4 ) to estimate the flow rate of the working fluid (e.g., the water in the fluid tank  801 ) to the capsule  809  and, therefore, the total amount of fluid added to the patient&#39;s GI tract. The fluid distribution system then controls the rate at which water is drawn through the suction valve to match the volume of fluid supplied to the patient in order to maintain a net balance between fluid supplied to and removed from the patient. 
         [0048]    As discussed above, the rate at which fluid from the supply tank  801  is allowed to enter the fluid supply lines  805  and, ultimately, the rate at which fluid is expelled from each exhaust port of the capsule  809  is controlled by a series of valves  807 .  FIG. 9  illustrates one example of a controllable pinch valve  900  that can be used in the fluid dispensing system  800  of  FIG. 8 . The pinch valve includes a controllable piston/actuator  901  that is moved linearly up and down. Downward movement of the piston  901  gradually pinches the supply line  903  to reduce the amount of pressurized fluid that is allowed to move through the supply line  903  and, thereby, controls the rate at which the fluid is expelled from the corresponding exhaust port of the capsule. The piston  901  can be lowered until the supply line  903  is sealed and no fluid is allowed to move through the supply line  903 . Among other things, the use of a pinch valve isolates the control mechanism of the valve from water—as such, only safe plastic components contact the water that will be expelled into the body of the patient. 
         [0049]    Finally,  FIG. 10  illustrates an example of a jet nozzle  1000  that is equipped on each exhaust port in some embodiments of the capsule system. The main body  1001  of the nozzle/jet is coupled to the distal end of the water supply line and received pressurized water. The diameter of the nozzle body is gradually reduced in an upper portion  1003  of the main body and curves towards an expulsion portion  1005  that is positioned at the exhaust port  1007  of the capsule body. The curved portion  1005  serves to redirect linear flow to be expelled laterally from the capsule body. This flow redirection also results in some forward thrust on the capsule. In other words, the jet design provides both lateral force to move the capsule, as well as forward force tending to push the capsule forward. This features adds to the stability of the capsule overall, as it opposes the lateral jet force much like both extensor and contractor muscles are used to keep a human hand in a stable, well-defined position. 
         [0050]    Thus, the invention provides, among other things, an endoscopic capsule system in which lateral movement is controlled by controllably expelling water laterally from the body of the capsule. Some embodiments utilize pressurized gas to provide water pressure creating a very stable water pressure source and a portable system with low power consumption requirements. Some embodiments utilized pinch valves for flow control while ensuring that the fluid that is injected into the body of the patient only contacts safe plastic components. In some embodiments, specially designed jets provide improved thrust for full hemispherical movement. Finally, in some embodiments, the use of an inertial sensor and a video system provide for computer-aided, closed-loop control for a reliable, user-friendly control interface. Various features and advantages of the invention are set forth in the following claims.