Patent Publication Number: US-2009227840-A1

Title: Capsule guiding system and capsule guiding method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from a PCT Application No. PCT/JP2007/066573, filed on Aug. 27, 2007, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a capsule guiding system and a capsule guiding method which allow a communication with a capsule endoscope via a human body communication and a guidance of the capsule endoscope through a detection of at least one of a position and a direction of the capsule endoscope. 
     2. Description of the Related Art 
     Recently, a swallowable capsule endoscope has appeared in the field of endoscopes. This capsule endoscope is provided with an imaging function and a radio function. The capsule endoscope moves inside a body cavity, for example, inside of organs such as the stomach and the small intestine according to the peristaltic movement thereof, and functions to capture images sequentially during a period which starts when the capsule endoscope is swallowed from a mouth of a patient for the purpose of an observation (examination) and ends when it is naturally excreted from a human body. 
     However, due to a communication with an outside of the human body through the radio function, the capsule endoscope has problems that a large power consumption causes a short operation period, and a large capacity occupied by a primary battery prevents downsizing and enhancing a high performance of the capsule endoscope. In response, a capsule endoscope which performs the communication with the outside of the human body through a human body communication has been proposed recently. In the capsule endoscope using the human body communication, an electric current is generated due to a potential difference between transmitting electrodes formed on a surface of the capsule endoscope, a voltage is induced between two receiving electrodes attached on a surface of the human body when the electric current flows through the human body, and data is received from the capsule endoscope via the induced voltage. Since the capsule endoscope using the human body communication does not need a high-frequency signal of several hundred MHz and can transmit data by a low-frequency signal of about 10 MHz, the consumption of the electric power can be enormously reduced, as disclosed in Japanese translation No. 2006-513001 of PCT international application and Japanese translation No. 2006-513670 of PCT international application 
     On the other hand, there is a system in which a capsule endoscope is provided with a magnet and subjected to an external rotating magnetic field, so that the capsule endoscope is rotated, and this rotation allows guiding the capsule endoscope in a subject body to a desired position and performing an examination, as disclosed in Japanese Patent Application Laid-Open No. 2004-255174 and Japanese Patent Application Laid-Open No. 2005-304638. 
     However, when it is intended to apply the system of using the external rotating magnetic field and guiding the capsule endoscope to the human body communication system described above, there are problems that a positional relationship between the transmitting electrodes of the capsule endoscope and the receiving electrodes would easily change due to a movement of the human body, at least one of a position and a direction of the capsule endoscope in the subject body cannot be detected precisely, and the guiding cannot be performed precisely as a result. 
     SUMMARY OF THE INVENTION 
     A capsule guiding system according to an aspect of the present invention includes an electrode pad which is arranged at an outside of a human body to perform a human body communication with a capsule endoscope and detect at least one of a position and a direction of the capsule endoscope; a magnetically guiding device which moves the capsule endoscope; a detector which detects a relative position between the electrode pad and the magnetically guiding device; a calculator which calculates at least one of the position and the direction of the capsule endoscope based on a detection value of the electrode pad, and calculates at least one of an absolute position and an absolute direction of the capsule endoscope with respect to the magnetically guiding device based on at least one of the position and the direction of the capsule endoscope and on the relative position detected by the detector; and a control unit which controls the magnetically guiding device based on at least one of the absolute position and the absolute direction. 
     A capsule guiding system according to another aspect of the present invention includes an electrode pad which is arranged at an outside of a human body to perform a human body communication with a capsule endoscope and detect at least one of a position and a direction of the capsule endoscope; a rigid part of a human body arranging device which fixedly arranges the electrode pad; a magnetically guiding device which moves the capsule endoscope; a calculator which calculates at least one of the position and the direction of the capsule endoscope based on a detection value of the electrode pad, adds at least one of a position and a direction of the rigid part of the human body arranging device with respect to the magnetically guiding device to at least one of the position and the direction of the capsule endoscope, and calculates at least one of an absolute position and an absolute direction of the capsule endoscope with respect to the magnetically guiding device; and a control unit which controls the magnetically guiding device based on at least one of the absolute position and the absolute direction. 
     A capsule guiding method according to still another aspect of the present invention includes calculating at least one of a relative position and a relative direction of a capsule endoscope inside a human body with respect to an electrode pad which performs a human body communication with the capsule endoscope and receives a human body communication signal based on the human body communication signal; calculating a relative position of the electrode pad with respect to a magnetically guiding device which forms an external magnetic field with respect to the capsule endoscope and magnetically guides the capsule endoscope; calculating at least one of an absolute position and an absolute direction of the capsule endoscope with respect to the magnetically guiding device based on at least one of the relative position and the relative direction of the capsule endoscope calculated in calculating the relative position/direction of the capsule endoscope and on the relative position of the electrode pad calculated in the calculating of the electrode pad position; and controlling the magnetically guiding device based on at least one of the absolute position and the absolute direction of the capsule endoscope calculated in calculating the absolute position/direction of the capsule endoscope. 
     A capsule guiding method according to still another aspect of the present invention includes calculating at least one of a position and a direction of a capsule endoscope inside a human body based on a human body communication signal received by an electrode pad which performs a human body communication with the capsule endoscope; and controlling a magnetic field which guides the capsule endoscope based on at least one of the position and the direction of the capsule endoscope calculated in calculating the position/direction of the capsule endoscope. 
     The above and other features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a schematic view showing a structure of a capsule guiding system according to a first embodiment of the present invention; 
         FIG. 2  is a view showing a structure of a capsule endoscope in the capsule guiding system shown in  FIG. 1 ; 
         FIG. 3  is a view showing a structure of a magnetic field generating device in the capsule guiding system shown in  FIG. 1 ; 
         FIG. 4  is a schematic view showing a structure of a capsule guiding system according to a modification of the first embodiment of the present invention; 
         FIG. 5  is a schematic view showing a structure of a capsule guiding system according to a second embodiment of the present invention; 
         FIG. 6  is a cross sectional view of a modification using a sheet member; 
         FIG. 7  is a schematic view of a structure of a capsule guiding system according to a third embodiment of the present invention; 
         FIG. 8  is a schematic view of a structure of a capsule guiding system according to a fourth embodiment of the present invention; and 
         FIG. 9  shows a specific example of a marker shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     Exemplary embodiments of a capsule guiding system and a capsule guiding method will be explained below with reference to the accompanying drawings. It should be noted that the present invention is not limited by those embodiments. 
     A first embodiment of the present invention will be explained.  FIG. 1  is a schematic view showing a structure of a capsule guiding system according to the first embodiment of the present invention.  FIG. 2  is a view showing a structure of a capsule endoscope shown in  FIG. 1 . In addition,  FIG. 3  is a view showing a structure of a magnetic field generating device shown in  FIG. 1 . In  FIGS. 1 to 3 , a capsule guiding system  10  includes: a magnetic field generating device  1  which generates a three-dimensional rotating magnetic field; a base  2  at least one part of which is provided in the magnetic field generating device  1 ; a bed  3  (a rigid part of a human body arranging device) which is movable in a Y direction on an upper part of the base  2  via a guide  8  and serves to arrange a human body  5 ; a plurality of electrode pads  7  which are fixedly arranged like a matrix on an upper part of the bed  3 ; and a conductive gel bed  4  (a conductive soft part of the human body arranging device) which is arranged on the bed  3  and the electrode pads  7  and formed of a soft member having a conductivity, for example, a conductive gel member. The human body  5  as a subject body has a capsule endoscope  6  which is swallowed from a mouth and can perform a human body communication, and becomes a state of being electrically conducted with the conductive gel member by lying down on the conductive gel bed  4 . Here, the state of being electrically conducted with the conductive gel bed  4  is maintained at least in a part of the human body  5  and positions of the electrode pads  7  do not move even when the human body  5  moves. Here, a conductive rubber and the like may be used instead of the conductive gel member. Besides, though the electrode pads are configured to be fixedly arranged like a matrix, the electrode pads may not be arranged necessarily like a matrix and it is only necessary that they are fixed at given positions, respectively. 
     Each of the electrode pads  7  is connected to a receiver  11  which receives voltages induced in the electrode pads  7  and outputs to a position/direction calculator  12  and an image processor  18  as a reception signal transmitted from the capsule endoscope  6  via the human body  5 . The position/direction calculator  12  calculates at least one of a relative position and a relative direction of the capsule endoscope  6  with respect to the bed  3  based on the voltage values induced in the electrode pads  7 . On the other hand, the image processor  18  generates image information transmitted from the capsule endoscope  6  based on the reception signal output from the receiver  11  and outputs to a control unit  13 . 
     The control unit  13  is connected to a display unit  15 , an input unit  16 , and a storage unit  17 , and makes the display unit  15  display and the storage unit  17  sequentially store the image information input from the image processor  18 . The input unit  16  outputs input information including various operations with respect to the magnetic field generating device  1  to the control unit  13 , and the control unit  13  gives an instruction to a guiding magnetic field controller  19  and controls a movement of the bed  3  with respect to the base  2  based on the input information. Information for controlling the movement of the bed  3  is also input to the position/direction calculator  12 . The position/direction calculator  12  corrects a movement amount of the bed  3  obtained from the information for controlling the movement of the bed  3  based on a reference position p of the bed  3  with respect to a reference position P of the magnetic field generating device  1 , finally calculates at least one of an absolute position and an absolute direction of the capsule endoscope  6  seen from the reference position P of the magnetic field generating device  1  based on a value of at least one of the relative position and the relative direction, which are described above, of the capsule endoscope  6  seen from the reference position p of the bed  3 , and transmits the calculated result to the control unit  13 . The control unit  13  transmits the value of at least one of the absolute position and the absolute direction of the capsule endoscope  6  to the guiding magnetic field controller  19 , makes the storage unit  17  temporarily store therein, and uses the value in displaying the position/direction of the capsule endoscope  6  on the display unit  15 . 
     The capsule endoscope  6  is shaped to have an opaque tubular case  20  whose one end has an opaque dome shape and the other end is blocked with a transparent dome-shaped case  21  as shown in  FIG. 2 . In an inside of the tubular case  20  and the dome-shaped case  21 , an illumination unit  31  realized by a light emitting diode and the like, a focusing lens  32 , and an imaging element  33  are provided at a side of the dome-shaped case  21  and an image of a subject around the side of the dome-shaped case  21  is captured. An imaging signal output from the imaging element  33  is processed by a signal processor  34 , output as an image signal from transmitting electrodes  22  and  23  to be described later via a transmitter  36 , and transmitted to the electrode pads  7  through the human body. Here, the transmitting electrodes  22  and  23  used for the human body communication are respectively formed on a surface of the dome-shaped case  21  and a surface of the dome opposite to the dome-shaped case  21  The transmitting electrode  22  formed on the surface of the dome-shaped case  21  is a transparent electrode realized by an indium tin oxide and the like. Besides, each of the transmitting electrodes  22  and  23  is a metal which is safe to the human body and has good corrosion resistance, and the transmitting electrode  23  is realized by SUS316L, gold, and the like for example. Moreover, the transmitting electrodes  22  and  23  are to be electrically connected to an inside of the human body via a body fluid and the like. 
     A battery  35  and a magnet  30  are arranged at a center part of the capsule endoscope  6 . Magnetic poles of the magnet  30  are arranged in a direction perpendicular to a longitudinal direction, that is, an axial direction of the capsule endoscope  6  and when a rotating magnetic field is applied around the axis, the magnet  30  is drawn and rotated around the axis like a rotor of a motor, so that the capsule endoscope  6  is rotated. Here, a spiral protrusion  24  is formed around a cylindrical part of the capsule endoscope  6  and the capsule endoscope  6  moves in the axial direction like a screw since the spiral protrusion  24  serves to screw together with a wall of a digestive tract inside the body when the capsule endoscope  6  is rotated. For example, when the capsule endoscope  6  is rotated in a direction A around the axis, the capsule endoscope  6  moves forward towards a direction F, and when the capsule endoscope  6  is rotated in a reverse direction to the direction A around the axis, the capsule endoscope  6  moves backward towards a direction B in  FIG. 2 . By this, the capsule endoscope  6  can move inside the body according to the rotating/guiding magnetic field of the magnetic field generating device  1 . 
     Besides, as shown in  FIG. 3 , the magnetic field generating device  1  has a configuration in which three pairs of electromagnets, each electromagnet producing a state where a coil is wound around a member such as a ferromagnet having a high dielectric constant, are fitted together respectively in three directions X, Y, and Z so that the human body  5  is put thereamong, and can form a three-dimensional external rotating magnetic field with respect to the capsule endoscope  6  by controlling a strength of the magnetic field generated in each direction. The external rotating magnetic field can be formed when the guiding magnetic field controller  19  controls a power distribution amount to each electromagnet pair of each direction based on an operational instruction from the input unit  16  via the control unit  13 . 
     Next, a capsule guiding method in which the capsule guiding system  10  having the above-described configuration uses the rotating magnetic field to guide the capsule endoscope  6  inside the human body  5  will be explained. First, the position/direction calculator  12  obtains, from each electrode pad  7 , a human body communication signal as a reception signal transmitted via the human body  5  from the capsule endoscope  6  inside the human body  5  and calculates at least one of a relative position and a relative direction of the capsule endoscope  6  with respect to each electrode pad  7  based on a voltage value of the human body communication signal from each electrode pad  7 , that is, voltage values induced in the electrode pads  7  (a capsule position/direction calculating step). Here, when the electrode pads  7  are fixedly arranged on the bed  3 , the position/direction calculator  12  calculates at least one of the relative position and the relative direction of the capsule endoscope  6  with respect to the bed  3  in the capsule position/direction calculating step as described above. 
     Subsequently, the position/direction calculator  12  calculates a relative position of each electrode pad  7  with respect to the magnetic field generating device  1  (an electrode pad position calculating step). In this case, the position/direction calculator  12  calculates the relative position of each electrode pad  7  with respect to the reference position P of the magnetic field generating device  1  based on the reference position p of the bed  3  with respect to the reference position P of the magnetic field generating device  1  and on a fixed position of each electrode pad  7  on the bed  3 , and corrects the calculated relative position of each electrode pad  7  based on the movement amount of the bed  3  described above. When a relative positional relationship between each electrode pad  7  and the bed  3  is always constant, the relative position of each electrode pad  7  with respect to the reference position P of the magnetic field generating device  1  may be set in advance based on the relative positional relationship between the reference position P of the magnetic field generating device  1  and the reference position p of the bed  3 . 
     Next, the position/direction calculator  12  calculates at least one of an absolute position and an absolute direction of the capsule endoscope  6  seen from the reference position P of the magnetic field generating device  1  based on at least one of the relative position and the relative direction of the capsule endoscope  6  with respect to each electrode pad  7  and the relative position of each electrode pad  7  with respect to the reference position P of the magnetic field generating device  1  (an absolute position/direction calculating step). The position/direction calculator  12  transmits a result of the calculated at least one of the absolute position and the absolute direction of the capsule endoscope  6  to the control unit  13  as described above. 
     Thereafter, the control unit  13  controls the magnetic field generating device  1  based on at least one of the absolute position and the absolute direction of the capsule endoscope  6  obtained from the position/direction calculator  12  (a magnetic field controlling step). In this case, the control unit  13  controls the magnetic field generating device  1  through a control of the guiding magnetic field controller  19  described above. The guiding magnetic field controller  19  makes the magnetic field generating device  1  form a rotating and guiding magnetic field to be applied to the capsule endoscope  6  so as to guide the capsule endoscope  6  to at least one of the position and the direction instructed by the control unit  13 . In this manner, the capsule guiding system  10  can allow a precise guidance of the capsule endoscope  6  within the human body  5  to at least one of a desired position and a desired direction. 
     In the first embodiment, since the electrode pads  7  and the human body are electrically in contact with each other via the conductive gel bed  4 , it is possible to perform a stable human body communication and detect at least one of the position and the direction of the capsule endoscope  6 . Besides, since the electrode pads  7  have a function of the human body communication as well as a function of detecting at least one of the position and the direction of the capsule endoscope  6 , a configuration can be simple in the first embodiment. Furthermore, since the electrode pads  7  are fixedly arranged on the bed  3 , the positional relationship between the magnetic field generating device  1  and the electrode pads  7  is already known and thereby the precision of at least one of the absolute position and the absolute direction of the capsule endoscope  6  can be virtually determined only based on the precision in the detection by the electrodes pads  7  of at least one of the relative position and the relative direction of the capsule endoscope  6 , and since the precision in the detection of at least one of the relative position and the relative direction by the electrode pads  7  as described above is high enough, the precision in the detection of at least one of the absolute position and the absolute direction of the capsule endoscope  6  can be enhanced ultimately in the first embodiment. In other words, the detected position/direction of the capsule endoscope  6  corresponds, in coordinates, to the position/direction of the capsule endoscope  6  which is supposed to be controlled by the magnetic field generating device  1 . As a result, a guiding control for moving the capsule endoscope  6  can be performed with high precision. 
     Though the conductive gel bed  4  is provided between the human body  5  and the bed  3  in the first embodiment described above, the present invention is not limited to this and a waterbed may be used instead of the conductive gel bed  4 , for example. Besides, as shown in  FIG. 4 , a bathtub  43  may be provided on the base  2 , the electrode pads  7  may be provided inside the bathtub  43 , and the bathtub  43  may be filled with a conductive fluid  44  such as fresh water, instead of the conductive gel bed  4 . As understood from the fact that a most part of the human body is constituted by moisture contents, water is conductive and has an impedance whose value is close to a human body impedance. Conversely, the impedance of the conductive gel bed  4  and the conductive fluid  44  is preferably close to about 20 ohms which is the impedance of the human body  5 . Moreover, to make the impedance of water correspond to the impedance of the human body, a physiologic saline may be used instead of fresh water. 
     In addition, the bed  3  may be configured to be movable to an X-axis direction and a Z-axis direction except for the Y-axis direction. Besides, though the bed is explained as an example of an object which arranges the human body  5 , an object such as a chair having a shape on which the human body is seated and another object having a columnar shape or a wall shape to be used in a way that the human body  5 , while standing, leans against the conductive soft part of the human body arranging device may be adopted except for the bed. 
     Next, a second embodiment of the present invention will be explained. Though all of the electrode pads  7  via the conductive gel bed  4  are treated as a target of the human body communication and the position/direction detection in the first embodiment described above, the human body communication and the position/direction detection in the second embodiment are performed without providing the conductive gel bed  4  and by treating only electrode pad(s)  7  that is/are in contact with the human body  5  on the bed  3  as a detection target. 
       FIG. 5  is a schematic view showing a structure of a capsule guiding system according to the second embodiment of the present invention. As shown in  FIG. 5 , a capsule guiding system  50  has a configuration eliminating the conductive gel bed  4  shown in the capsule guiding system  10  and is provided with a plurality of pressure sensors  57  which are respectively in contact with electrode pads  7  or placed in the vicinity of the electrode pads  7  and detect a contact with a human body. Besides, a detection result of each pressure sensor  57  is transmitted to the receiver  11  and a selector  51  provided in the receiver  11  outputs, to the position/direction calculator  12  and the image processor  18 , only a detection result of an electrode pad  7  corresponding to a pressure sensor  57  which has detected a pressure not less than a predetermined value, the pressure not less than the predetermined value allowing to assume that the human body is in contact with the corresponding electrode pad  7 . Other constituents are the same as those in the first embodiment. 
     Since the conductive gel bed  4  is not necessary in the second embodiment, it is possible to downsize the capsule guiding system. 
     Though the pressure sensors  57  are used as a sensor which detects a contact with a human body in the second embodiment described above, the present invention is not limited to this and a temperature sensor or a mechanical switch may be used, for example. 
     Furthermore, the electrode pad  7  may be separated into an electrode pad  7   a  whose center has a concave shape and an electrode pad  7   b  whose center has a convex shape, the concave part and the convex part may be engaged to be joined together like a hook, and a sheet member  53  which has an arrangement in which the electrode pad  7   a  corresponds to the electrode pad  7   b  may be used as shown in  FIG. 6 . By this, the sheet member  53  can be changed, so that a hygienic control and a maintenance can be easily performed when an examination is performed repeatedly. 
     Next, a third embodiment of the present invention will be explained. In contrast to the configuration of fixedly arranging the electrode pads  7  on the bed  3  in the first and the second embodiments described above, electrode pads are arranged to move in accordance with a movement of a human body in the third embodiment. 
       FIG. 7  is a schematic view of a structure of a capsule guiding system according to the third embodiment of the present invention. A capsule guiding system  60  shown in  FIG. 7  is provided with a gel bed  64  (the soft part of the human body arranging device) instead of the conductive gel bed  4  in the capsule guiding system  10 , and a plurality of electrode pads  67  arranged like a matrix are attached to a side of the human body  5  on the gel bed  64 . Thus, the electrode pads  67  change in position in accordance with a movement of the human body  5 . Therefore, sensors  61  which are respectively associated with the electrode pads  67  are provided on a side of the bed  3  of the gel bed  64  or on an upper surface of the bed  3 , each sensor  61  being capable of detecting a positional change of the associated electrode pad  67 . The sensor  61  is, for example, realized by an ultrasonic sensor and detects a distance from or a positional change of the associated electrode pad  67  by using an echo of the ultrasonic generated by the ultrasonic sensor. The detection result is output to the position/direction calculator  12  and the position/direction calculator  12  corrects the position of the electrode pad  67  based on the position of the electrode pad  67  detected by the sensor  61 . Other constituents are the same as those in the first embodiment. 
     It is possible to perform a stable human body communication and detect the position/direction of the capsule endoscope with high precision in the third embodiment, too. 
     Next, a fourth embodiment of the present invention will be explained. Though the position of an electrode pad is detected from the side of the bed  3  in the third embodiment described above, the positional change of an electrode pad is detected from a side opposite to the bed  3 , that is, from an outside in the fourth embodiment. 
       FIG. 8  is a schematic view of a structure of a capsule guiding system  70  according to the fourth embodiment of the present invention. In  FIG. 8 , a plurality of electrode pads  77  are provided on a surface of the human body  5  and voltage values detected in the electrode pads  77  are output to the receiver  11 . A Marker  71  having a pattern shown in  FIG. 9  is attached to an outside surface of each electrode pad  77 . 
     On the other hand, two imaging devices  72  and  73  which image the plurality of markers  71  are arranged at a given distance at an outside of the human body  5 , an image processing, performed by an image processor  74 , for calculating a three-dimensional position seen from each of the imaging devices  72  and  73  to each marker  71  is performed on the image captured by each of the imaging devices  72  and  73 , and a result of the processing is output to the position/direction calculator  12 . Since positions of the imaging devices  72  and  73  with respect to the reference position P of the magnetic field generating device  1  are known and fixed, the position/direction calculator  12  can calculate a position of each electrode pad  77  with respect to the reference position P of the magnetic field generating device  1  and can calculate at least one of an absolute position and an absolute direction of the capsule endoscope  6  with respect to the reference position P of the magnetic field generating device  1  based on the three-dimensional position of each electrode pad  77  and on at least one of a relative position and a relative direction, calculated depending on each electrode pad  77 , of the capsule endoscope  6 . 
     It is possible to precisely detect at least one of the absolute position and the absolute direction of the capsule endoscope  6  in the fourth embodiment, too. 
     Though the human body  5  is configured to lie down on the bed  3  in the fourth embodiment described above, the present invention is not limited to this and an application to a case where the human body  5  stands on his/her own feet is also available. Besides, an application to another case where the human body  5  is seated on a chair and the like is also available. 
     Besides, though the markers  71  are provided to obtain three-dimensional positions of the electrode pads  77  respectively through a stereovision of the markers  71 , the present invention is not limited to this and magnetic sensors such as a resonance coil, an LC marker, an MI (magnetoimpedance) sensor, and an MR (magnetoresistance) sensor are provided instead of the markers  71  and each magnetic sensor may detect a certain guiding magnetic field to detect the three-dimensional position of each electrode pad. 
     Moreover, an ultrasonic scanner, a three-dimensional scanner using a light, and the like may be used to scan a surface of the human body on a side of the electrode pad, detect a movement of the human body based on a scanned image, and detect or estimate the three-dimensional position of each electrode pad based on the detection result. 
     Furthermore, a plurality of mechanical displacement gauges may be provided at a tip end of an arm which is not shown, and a displacement of each electrode pad may be converted to a mechanical displacement to detect the three-dimensional position of each electrode pad while the mechanical displacement gauge is pressed onto the electrode pad. Here, the electrode pad may be provided at a tip end of the mechanical displacement gauge. By this, a contact between a human body and an electrode pad becomes stable and the configuration becomes simple. 
     Though transmitting electrodes of the capsule endoscope  6  are realized by the transmitting electrode  22  which is transparent and provided at the imaging side, and the transmitting electrode  23  having a dome shape part at the opposite side to the transmitting electrode  22  in the embodiments 1 to 4 described above, the present invention is not limited to this, and an arrangement and a pattern of a pair of transmitting electrodes can be arbitrarily determined. For example, a pair of transmitting electrodes may be provided on the spiral protrusion  24 , or double spiral protrusions may be provided and a transmitting electrode may be provided to each spiral protrusion. This configuration allows a contact state between the capsule endoscope  6  and the human body  5  to be stable 
     Besides, to enhance communication characteristics of the human body communication, ionized water whose impedance is close to the impedance of the human body  5  may be taken at the time of an examination, so that the contact state between the capsule endoscope  6  and the human body  5  can be improved. Furthermore, though the method of causing a rotation of the spiral protrusion is explained as a method of guiding the capsule endoscope  6 , the present invention is not limited to this, and an application to a method of using a magnetic gradient to pull and guide the capsule endoscope  6  through a magnetic attraction force is also available. 
     In the capsule guiding system according to the present invention, since the detector detects the relative position between the electrode pad and the magnetically guiding device; and the calculator calculates at least one of the position and the direction of the capsule endoscope based on the detection value of the electrode pad and calculates at least one of the absolute position and the absolute direction of the capsule endoscope with respect to the magnetically guiding device based on at least one of the position and the direction of the capsule endoscope and on the relative position detected by the detector, at least one of the absolute position and the absolute direction of the capsule endoscope can be detected precisely and the capsule endoscope can be guided precisely as a result even in the case of performing the human body communication. 
     Besides, in the capsule guiding system according to the present invention, since the electrode pad is fixedly arranged on the rigid part of the human body arranging device; and the calculator calculates at least one of the position and the direction of the capsule endoscope based on the detection value of the electrode pad, adds at least one of the position and the direction of the rigid part of the human body arranging device with respect to the magnetically guiding device to at least one of the position and the direction of the capsule endoscope, and calculates at least one of the absolute position and the absolute direction of the capsule endoscope with respect to the magnetically guiding device, at least one of the absolute position and the absolute direction of the capsule endoscope can be detected precisely with a simple configuration and the capsule endoscope can be guided precisely as a result even in the case of performing the human body communication. 
     Moreover, in the capsule guiding method according to the present invention, since at least one of the relative position and the relative direction of the capsule endoscope with respect to the electrode pad which performs the human body communication with the capsule endoscope inside the human body to receive a human body communication signal is calculated based on the human body communication signal; the relative position of the electrode pad with respect to the magnetically guiding device which forms an external magnetic field with respect to the capsule endoscope and magnetically guides the capsule endoscope is calculated; at least one of the absolute position and the absolute direction of the capsule endoscope with respect to the magnetically guiding device is calculated based on at least one of the relative position and the relative direction of the capsule endoscope and on the relative position of the electrode pad; and the magnetically guiding device is controlled based on at least one of the absolute position and the absolute direction of the capsule endoscope, at least one of the absolute position and the absolute direction of the capsule endoscope can be detected precisely and the capsule endoscope can be guided precisely as a result even in the case of performing the human body communication. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.