Capsule-type medical apparatus, guidance system and guidance method therefor, and intrasubject insertion apparatus

Abstract

Using a guidance system with a simple configuration, propulsive motion along a longitudinal direction and changing of the propulsion direction are easily performed with good precision and stability. There is provided a capsule-type medical apparatus 201 which is inserted into the body of a subject and is guided by an external magnetic field, the capsule-type medical apparatus 201 comprising: a substantially cylindrical capsule 202 ; a propulsion mechanism 207 for converting rotary motion about a longitudinal axis R of the capsule 202 into propulsive motion along the longitudinal axis R; a magnet 205 accommodated inside the capsule 202 and disposed in such a manner that the magnetic-pole direction thereof can be switched between a direction along the longitudinal axis R and a direction intersecting the longitudinal axis R; and a securing portion 212 for securing the magnet 205 to the capsule 202 in each of the switched states of the magnetic-pole direction.

1 . A capsule-type medical apparatus which is inserted into the body of a subject and is guided by an external magnetic field, the capsule-type medical apparatus comprising:
 a substantially cylindrical capsule;   a propulsion mechanism for converting rotary motion about a longitudinal axis of the capsule into propulsive motion along the longitudinal axis;   a magnet accommodated inside the capsule and disposed in such a manner that a magnetic-pole direction thereof can be switched between a direction along the longitudinal axis and a direction intersecting the longitudinal axis; and   a securing portion for securing the magnet to the capsule in each of the switched states of the magnetic-pole direction.   
     
     
         2 . The capsule-type medical apparatus according to  claim 1 , wherein the propulsion mechanism is a spiral mechanism provided on an outer circumferential surface of the capsule. 
     
     
         3 . The capsule-type medical apparatus according to  claim 1 , wherein
 the magnet is made of a permanent magnet, and   the securing portion includes an engagement member which is engaged with the magnet at a location where magnetic poles are oriented in a direction along the longitudinal axis and at a location where the magnetic poles are oriented in a direction intersecting the longitudinal axis.   
     
     
         4 . The capsule-type medical apparatus according to  claim 1 , wherein
 the magnet is made of a permanent magnet, and   the securing portion includes a magnetic material which is held in contact with the magnet at a location where the magnetic poles are oriented in a direction along the longitudinal axis and at a location where the magnetic poles are oriented in a direction intersecting the longitudinal axis.   
     
     
         5 . The capsule-type medical apparatus according to  claim 1 , comprising a magnetic-pole-direction switching device for switching the magnetic-pole direction of the magnet. 
     
     
         6 . The capsule-type medical apparatus according to  claim 1 , comprising:
 a magnetic-pole-direction switching device for switching the magnetic-pole direction of the magnet, wherein   the magnet is made of a permanent magnet,   the securing portion includes an electromagnet which is held in contact with the magnet at a location where the magnetic poles are oriented in a direction along the longitudinal axis and at a location where the magnetic poles are oriented in a direction intersecting the longitudinal axis, and   the magnetic-pole-direction switching device includes a magnetic-pole switching device for switching the magnetic poles of the electromagnet.   
     
     
         7 . The capsule-type medical apparatus according to  claim 1 , comprising:
 a magnetic-pole-direction switching device for switching the magnetic-pole direction of the magnet, wherein   the magnet is made of a permanent magnet, and   the magnetic-pole-direction switching device includes a motor for pivoting the magnet about an axis along a radial direction of the capsule.   
     
     
         8 . The capsule-type medical apparatus according to  claim 3 , comprising:
 a magnetic-pole-direction switching device for switching the magnetic-pole direction of the magnet, wherein   the magnetic-pole-direction switching device includes a motor for pivoting the magnet about an axis along a radial direction of the capsule.   
     
     
         9 . The capsule-type medical apparatus according to  claim 1 , comprising:
 a magnetic-pole-direction switching device for switching the magnetic-pole direction of the magnet, wherein   the magnet is made of an electromagnet, and   the securing portion and the magnetic-pole-direction switching device include a magnetic-pole switching device for switching and holding the magnetic poles of the electromagnet.   
     
     
         10 . The capsule-type medical apparatus according to  claim 2 , wherein
 the spiral mechanism is separated from an outer surface of the capsule, and   the capsule-type medical apparatus includes a spiral-outer-diameter change-imparting portion for changing a spiral-outer-diameter of the spiral mechanism which is separated in a diameter direction with respect to the outer surface of the capsule.   
     
     
         11 . The capsule-type medical apparatus according to  claim 10 , wherein
 the spiral-outer-diameter change-imparting portion secures either one end or the other end of the spiral mechanism movably in an outer circumferential direction of the capsule and changes the spiral-outer-diameter of the spiral mechanism by moving the securing position in the outer circumferential direction of the capsule.   
     
     
         12 . The capsule-type medical apparatus according to  claim 10 , wherein
 the spiral-outer-diameter change-imparting portion changes the spiral-outer-diameter of the spiral mechanism which is separated from the outer surface of the capsule by inflating and deflating the spiral mechanism in a spiral direction.   
     
     
         13 . The capsule-type medical apparatus according to  claim 10 , wherein
 the spiral-outer-diameter change-imparting portion provides a balloon between the capsule and the spiral mechanism and changes the spiral-outer-diameter of the spiral mechanism by inflating and deflating the balloon.   
     
     
         14 . A capsule-type medical-apparatus guidance system comprising:
 a capsule-type medical apparatus according to  claim 1 ;   a magnetic-field generating apparatus, disposed outside a working area of the capsule-type medical apparatus, for generating an external magnetic field which acts on the magnet inside the capsule-type medical apparatus; and   a magnetic-field control apparatus for controlling the external magnetic field acting on the magnet from the magnetic-field generating apparatus.   
     
     
         15 . The capsule-type medical-apparatus guidance system according to  claim 14 , comprising:
 a capsule-orientation detection apparatus for detecting an orientation of the capsule-type medical apparatus, wherein   the magnetic-field control apparatus controls a direction of the external magnetic field at a position of the capsule-type medical apparatus according to the orientation of the capsule-type medical apparatus detected by the capsule-orientation detection apparatus.   
     
     
         16 . A capsule-type medical-apparatus guidance method for guiding a capsule-type medical apparatus according to  claim 1 , comprising the steps of:
 propelling the capsule-type medical apparatus in the longitudinal direction by switching and fixing the magnetic-pole direction of the magnet to the direction intersecting the longitudinal direction and applying an external magnetic field which rotates about the longitudinal axis; and   changing the propulsion direction of the capsule-type medical apparatus by switching and fixing the magnetic-pole direction of the magnet to the direction along the longitudinal axis and applying an external magnetic field which is formed in an arbitrary direction.   
     
     
         17 . An intrasubject insertion apparatus comprising:
 an insertion portion main body for insertion into a subject;   a rotation mechanism for rotating the insertion portion main body;   a spiral-structured portion which converts rotary motion of the insertion portion main body due to the rotating mechanism into a propulsive force and which is separated in a diameter direction with respect to an outer surface of the insertion portion main body; and   a spiral-outer-diameter change-imparting portion for changing a spiral-outer-diameter of the spiral-structured portion which is separated in the diameter direction with respect to the outer surface of the insertion portion main body.   
     
     
         18 . The intrasubject insertion apparatus according to  claim 17 , wherein
 the spiral-outer-diameter change-imparting portion secures either one end or the other end of the spiral-structured portion movably in an outer circumferential direction of the insertion-portion main body and changes the spiral-outer-diameter of the spiral-structured portion by moving the securing position in the outer circumferential direction of the insertion-portion main body.   
     
     
         19 . The intrasubject insertion apparatus according to  claim 17 , wherein
 the spiral-outer-diameter change-imparting portion changes the spiral-outer-diameter of the spiral-structured portion which is separated from the outer surface of the insertion-portion main body by inflating and deflating the spiral-structured portion in a spiral direction.   
     
     
         20 . The intrasubject insertion apparatus according to  claim 17 , wherein
 the spiral-outer-diameter change-imparting portion provides a balloon between the insertion-portion main body and the spiral-structured portion and changes the spiral-outer-diameter of the spiral-structured portion by inflating and deflating the balloon.