Body-insertable device system and in-vivo observation method

• US 20070221233A1
• Filed: 12/28/2006
• Published: 09/27/2007
• Est. Priority Date: 12/28/2005
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Medical Systems Corporation (Olympus Corporation)
• Inventors: Kawano, Hironao, Takizawa, Hironobu, Segawa, Hidetake, Ito, Hideo, Aoki, Isao, Hirakawa, Katsumi, Kobayashi, Satomi
• Granted Patent: US 8,162,821 B2
• Time in Patent Office: Days
• US Class Current: 128/899
• CPC Class Codes: A61B 1/00016 using wireless means
• CPC Class Codes: A61B 1/00036 Means for power saving, e.g. sleeping mode
• CPC Class Codes: A61B 1/00147 Holding or positioning arrangements
• CPC Class Codes: A61B 1/00156 using self propulsion
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: A61B 1/273 for the upper alimentary canal, e.g. oesophagoscopes, gastroscopes
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/073 Intestinal transmitters

Abstract

An object of the present invention is to actively control at least one of the position and direction of the imaging field in a subject and to observe a desired observed region in the subject certainly in a short period of time. A body-insertable device system according to the present invention includes a capsule endoscope 1 introduced into a subject and a permanent magnet 3. An imaging unit of the capsule endoscope 1 for taking an image inside the subject is fixed in a casing. The capsule endoscope 1 includes a drive unit for changing at least one of the position and posture of the casing in the liquid 2a which is also introduced in the subject 100. The permanent magnet 3 controls the operation of the drive unit for changing at least one of the position and posture of the casing in the liquid 2a.

Claims

1. A body-insertable device system, comprising:

a casing to be introduced into a subject and including at least one imaging unit having a specific observing direction for the subject;

liquid to be introduced into the subject; and

a drive unit which changes at least one of a position and posture of the casing in the liquid.

2. The body-insertable device system according to claim 1, wherein a specific gravity of the casing is smaller than a specific gravity of the liquid.

3. The body-insertable device system according to claim 2, wherein the specific gravity of the casing is greater than a half of the specific gravity of the liquid.

4. The body-insertable device system according to claim 2, wherein the imaging unit is disposed inside the casing so that the observing direction is directed downward in a vertical direction when the casing is placed in the liquid.

5. The body-insertable device system according to claim 2, further comprising a foaming agent for generating gas in the subject,

wherein the imaging unit is disposed inside the casing so that the observing direction is directed upward in a vertical direction when the casing is placed in the liquid.

6. The body-insertable device system according to claim 1, wherein a specific gravity of the casing is larger than a specific gravity of the liquid.

7. The body-insertable device system according to claim 1, wherein the drive unit includes a specific gravity changing unit which changes the specific gravity of the casing.

8. The body-insertable device system according to claim 7, wherein the specific gravity changing unit includes a separation unit and changes the specific gravity of the casing by separating the separation unit from the casing.

9. The body-insertable device system according to claim 8, wherein

the specific gravity of the casing before separating the separation unit is smaller than the specific gravity of the liquid;

and

a specific gravity of the separation unit is smaller than the specific gravity of the liquid.

10. The body-insertable device system according to claim 8, wherein

the specific gravity of the casing before separating the separation unit is larger than the specific gravity of the liquid;

and

a specific gravity of the separation unit is greater than the specific gravity of the liquid.

11. The body-insertable device system according to claim 8, wherein the separation unit is provided at an opposite side of the imaging unit.

12. The body-insertable device system according to claim 11, wherein

the specific gravity of the casing before separating the separation unit is smaller than the specific gravity of the liquid;

and

the imaging unit is provided inside the casing so as to take an image downward in a vertical direction when the casing is placed in the liquid.

13. The body-insertable device system according to claim 11, wherein

the specific gravity of the casing before separating the separation unit is greater than the specific gravity of the liquid;

and

the imaging unit is provided inside the casing so as to take an image upward in a vertical direction when the casing is placed in the liquid.

14. The body-insertable device system according to claim 8, wherein the specific gravity changing unit connects the casing and the separation unit and further includes a solution part which resolves in a stomach in the subject.

15. The body-insertable device system according to claim 8, wherein the specific gravity changing unit further includes an actuator for separating the connection between the casing and the separation unit.

16. The body-insertable device system according to claim 1, wherein

the casing includes a plurality of the imaging units, and

observing directions of the plurality of imaging units are different.

17. The body-insertable device system according to claim 1, wherein the drive unit is a propelling unit which changes at least one of a position and posture of the casing by propelling the casing in the liquid.

18. The body-insertable device system according to claim 1, wherein the drive unit is a vibration unit which changes at least one of a position and posture of the casing by vibrating the casing in the liquid.

19. The body-insertable device system according to claim 1, wherein the drive unit includes

a magnetic material provided in the casing;

and

a magnetic field generator which generates a magnetic field for the magnetic material.

20. The body-insertable device system according to claim 19, wherein the drive unit includes a first magnetic field strength changing unit which changes a strength of a magnetic field generated by the magnetic field generator for the magnetic material.

21. The body-insertable device system according to claim 20, wherein the magnetic field generator is an electrical magnet;

and

the first magnetic field strength changing unit changes current applied to the electrical magnet.

22. The body-insertable device system according to claim 20, wherein the magnetic field generator is an electrical magnet or a permanent magnet;

and

the first magnetic field strength changing unit includes a magnetic field generator distance changing unit which changes a distance between the subject and the magnetic field generator.

23. The body-insertable device system according to claim 20, wherein the magnetic field generator includes a plurality of permanent magnets having different magnetic field strength.

24. The body-insertable device system according to claim 19, wherein the magnetic material has a specific magnetization direction;

and

the drive unit includes a first posture controller which controls a posture of the casing in the liquid.

25. The body-insertable device system according to claim 24, wherein an angle defined by the magnetization direction and an observing direction of the imaging unit is 0 degrees or larger and less than 90 degrees.

26. The body-insertable device system according to claim 24, wherein the specific gravity of the casing is greater than the specific gravity of the liquid.

27. The body-insertable device system according to claim 26, wherein the magnetic field generator is placed above or under the liquid in the subject in a vertical direction.

28. The body-insertable device system according to claim 27, wherein the first posture controller is a first magnetic field generator direction changing unit which changes the direction of the magnetic field generator.

29. The body-insertable device system according to claim 27, wherein the first posture controller is a first magnetic field generator horizontal position changing unit which changes a horizontal position of the magnetic field generator.

30. The body-insertable device system according to claim 26, wherein the magnetic field generator is provided in a horizontal direction with respect to the liquid in the subject.

31. The body-insertable device system according to claim 30, wherein the first posture controller is a second magnetic field generator direction changing unit which changes a direction of the magnetic field generator.

32. The body-insertable device system according to claim 30, wherein the first posture controller is a first magnetic field generator vertical position changing unit which changes a vertical position of the magnetic field generator.

33. The body-insertable device system according to claim 26, wherein

the magnetic field generator includes a plurality of magnetic field generating elements;

and

the first posture controller is a second magnetic field strength changing unit which changes a strength of a magnetic field generated by the plurality of magnetic field generating elements for the magnetic material.

34. The body-insertable device system according to claim 24, wherein the specific gravity of the casing is smaller than the specific gravity of the liquid.

35. The body-insertable device system according to claim 34, wherein the magnetic field generator is placed above or under the liquid in the subject in a vertical direction.

36. The body-insertable device system according to claim 34, wherein

the magnetic field generator includes a first magnetic attracting force generator which generates magnetic attracting force;

and

the first posture controller includes a magnetic attracting force generator direction changing unit which changes a direction of the first magnetic attracting force generator.

37. The body-insertable device system according to claim 34, wherein the magnetic field generator includes

a second magnetic attracting force generator which generates magnetic attracting force;

and

one or more magnetic field generating elements provided around the second magnetic attracting force generator, and

the first posture controller includes a third magnetic field strength changing unit which changes a strength of a magnetic field generated by the magnetic field generating element for the magnetic material.

38. The body-insertable device system according to claim 37, wherein

the plurality of magnetic field generating elements are composed of four magnetic field generating elements;

and

the four magnetic field generating elements are provided around the second magnetic attracting force generator substantially evenly.

39. The body-insertable device system according to claim 37, wherein the first posture controller includes a magnetic field generator rotating mechanism which rotates the magnetic field generator around the second magnetic attracting force generator.

40. The body-insertable device system according to claim 24, wherein

an angle defined by the magnetization direction and an observation direction of the imaging unit is substantially perpendicular;

the magnetic field generator generates a rotational magnetic field; and

the first posture controller includes a rotational magnetic field face changing unit which changes a rotational face of the rotational magnetic field.

41. The body-insertable device system according to claim 24, wherein

an angle defined by the magnetization direction and an observation direction of the imaging unit is substantially perpendicular;

and

center of gravity of the casing is set such that the magnetization direction is substantially parallel to a liquid surface of the liquid when the magnetic field generator is not generating magnetic field.

42. The body-insertable device system according to claim 19, wherein the drive unit include a first horizontal position controller which controls a horizontal position of the casing in the liquid.

43. The body-insertable device system according to claim 42, wherein the specific gravity of the casing is smaller than the specific gravity of the liquid.

44. The body-insertable device system according to claim 43, wherein

the magnetic material has a specific magnetization direction;

and

the drive unit includes a second posture controller which controls a posture of the casing in the liquid.

45. The body-insertable device system according to claim 44, wherein the magnetic field generator is placed above or under the liquid in the subject in a vertical direction.

46. The body-insertable device system according to claim 43, wherein the magnetic material has a specific magnetization direction;

and

the first horizontal position controller controls a posture of the casing in the liquid.

47. The body-insertable device system according to claim 46, wherein the magnetic field generator is placed horizontally with respect to the liquid in the subject.

48. The body-insertable device system according to claim 42, wherein the magnetic field generator is a third magnetic attracting force generator which generates a magnetic attracting force to the magnetic material.

49. The body-insertable device system according to claim 48, wherein the magnetic material has a specific magnetization direction;

and

the center of gravity of the casing is set such that the magnetization direction and the liquid surface of the liquid have an angular difference of 10 degrees or larger when the magnetic field generator is not generating magnetic field.

50. The body-insertable device system according to claim 49, wherein

the third magnetic attracting force generator is placed above or under the liquid in the subject in a vertical direction;

and

a vertical component of the magnetization direction of the third magnetic attracting force generator and a vertical component of the magnetization direction of the magnetic material are in the same direction.

51. The body-insertable device system according to claim 49, wherein

the third magnetic attracting force generator is placed horizontally with respect to the liquid in the subject;

and

a vertical component of the magnetization direction of the third magnetic attracting force generator and a vertical component of the magnetization direction of the magnetic material are in an opposite direction.

52. The body-insertable device system according to claim 48, wherein

the magnetic material has a specific magnetization direction;

and

center of gravity of the casing is set such that the magnetization direction is substantially parallel to the liquid surface of the liquid when the magnetic field generator is not generating magnetic field.

53. The body-insertable device system according to claim 52, wherein

the third magnetic attracting force generator is placed above or under the liquid in the subject in a vertical direction;

and

the magnetization direction of the third magnetic attracting force generator is substantially parallel to the liquid surface of the liquid.

54. The body-insertable device system according to claim 52, wherein

the third magnetic attracting force generator is placed horizontally with respect to the liquid in the subject;

and

the magnetization direction of the third magnetic attracting force generator is substantially parallel to the liquid surface of the liquid.

55. The body-insertable device system according to claim 48, wherein the first horizontal position controller is a second magnetic field generator horizontal position changing unit which changes a horizontal position of the magnetic field generator.

56. The body-insertable device system according to claim 55, wherein the first horizontal position controller includes a fourth magnetic field strength changing unit which changes a strength of a magnetic field generated by the magnetic field generator for the magnetic material.

57. The body-insertable device system according to claim 48, wherein

the magnetic field generator includes a plurality of magnetic field generating elements;

the plurality of magnetic field generating elements are arranged in array; and

the first horizontal position controller includes a fifth magnetic field strength changing unit which changes a strength of a magnetic field generated by the plurality of magnetic field generating elements for the magnetic material.

58. The body-insertable device system according to claim 42, wherein the magnetic field generator is a first magnetic repulsive force generator which generates magnetic repulsive force for the magnetic material.

59. The body-insertable device system according to claim 58, wherein

the magnetic material has a specific magnetization direction;

and

the center of gravity of the casing is set such that the magnetization direction and the liquid surface have an angular difference of 10 degrees or larger when the magnetic field generator is not generating magnetic field.

60. The body-insertable device system according to claim 59, wherein

the first magnetic repulsive force generator is placed above and under the liquid in the subject in a vertical direction;

and

a vertical component of the magnetization direction of the first magnetic repulsive force generator and a vertical component of the magnetization direction of the magnetic material are in an opposite direction.

61. The body-insertable device system according to claim 59, wherein

the first magnetic repulsive force generator is placed horizontally with respect to the liquid in the subject;

and

a vertical component of the magnetization direction of the first magnetic repulsive force generator and a vertical component of the magnetization direction of the magnetic material are in a same direction.

62. The body-insertable device system according to claim 61, wherein a vertical position of the first magnetic repulsive force generator substantially coincides a position of the liquid surface of the liquid.

63. The body-insertable device system according to claim 59, wherein a strength of a magnetic field generated by the first magnetic repulsive force generator at an arbitrary position on an arbitrary horizontal plane is smaller than the strength of a magnetic field generated by the first magnetic repulsive force generator at the arbitrary position on the arbitrary horizontal plane.

64. The body-insertable device system according to claim 63, wherein the first magnetic repulsive force generator is in a substantially cylindrical shape and a permanent magnet having a magnetization direction of axial direction.

65. The body-insertable device system according to claim 63, wherein the first horizontal position controller includes a magnetic field balance changing unit which changes a balance of a magnetic field generated by the first magnetic repulsive force generator at an arbitrary horizontal plane.

66. The body-insertable device system according to claim 65, wherein the magnetic field balance changing unit includes a first magnetic repulsive force generator inclination changing unit which changes an inclination of the first magnetic repulsive force generator.

67. The body-insertable device system according to claim 63, wherein

the first magnetic repulsive force generator includes a plurality of magnetic field generating elements;

and

the plurality of magnetic field generating elements are arranged in array.

68. The body-insertable device system according to claim 67, wherein

the first horizontal position controller includes a magnetic field balance changing unit which changes a balance of a magnetic field generated by the first magnetic repulsive force generator at an arbitrary horizontal plane;

and

the magnetic field balance changing unit includes a magnetic field generating element relative position changing unit which changes a relative position of the plurality of magnetic field generating elements.

69. The body-insertable device system according to claim 67, wherein

the first horizontal position controller includes a magnetic field balance changing unit which changes a balance of a magnetic field generated by the first magnetic repulsive force generator at an arbitrary horizontal plane;

and

the magnetic field balance changing unit includes a sixth magnetic field strength changing unit which changes strength of magnetic fields generated by the plurality of magnetic field generating elements for the magnetic material.

70. The body-insertable device system according to claim 63, wherein

the first magnetic repulsive force generator is composed of two magnetic field generating elements in different sizes arranged on a same axis;

and

magnetization directions of the two magnetic field generating element are different.

71. The body-insertable device system according to claim 59, wherein the first horizontal position controller is a third magnetic field generator horizontal position changing unit which changes a horizontal position of the first magnetic repulsive force generator.

72. The body-insertable device system according to claim 58, wherein the magnetic material is in a substantially cylindrical shape and includes magnetic poles at outer and inner peripheries of the cylindrical shape.

73. The body-insertable device system according to claim 72, wherein the magnetization direction is substantially parallel to the liquid surface of the liquid.

74. The body-insertable device system according to claim 42, wherein

the magnetic field generator generates a magnetic attracting force and a magnetic repulsive force;

and

the magnetic field generator includes a attracting/repulsive force switching unit which switches the magnetic force generated by the magnetic field generator using the generated magnetic attracting force and magnetic repulsive force.

75. The body-insertable device system according to claim 74, wherein

the magnetic material has a specific magnetization direction;

and

center of gravity of the casing is set such that the magnetization direction and the liquid surface have an angular difference of 10 degrees or larger when the magnetic field generator is not generating magnetic field.

76. The body-insertable device system according to claim 75, wherein the attracting/repulsive force switching unit is a second magnetic field generator vertical position changing unit which changes a vertical position of the magnetic field generator.

77. The body-insertable device system according to claim 75, wherein the attracting/repulsive force switching unit is a third magnetic field generator direction changing unit which changes a direction of the magnetic field generator.

78. The body-insertable device system according to claim 75, wherein

the magnetic field generator includes an electrical magnet;

and

the attracting/repulsive force switching unit is a electrical magnet current switching unit which switches the direction of the current applied to the electrical magnet.

79. The body-insertable device system according to claim 19, wherein the drive unit includes a vertical position controller for controlling a vertical position of the casing in the liquid.

80. The body-insertable device system according to claim 79, wherein a specific gravity of the casing is smaller than a specific gravity of the liquid.

81. The body-insertable device system according to claim 80, wherein the specific gravity of the casing is greater than a half of the specific gravity of the liquid.

82. The body-insertable device system according to claim 80, wherein

the magnetic field generator is a fourth magnetic attracting force generator which generates a magnetic attracting force for the magnetic material;

and

the fourth magnetic attracting force generator is placed under the liquid in the subject in a vertical direction.

83. The body-insertable device system according to claim 82, wherein a vertical component of the magnetization direction of the fourth magnetic attracting force generator and a vertical component of the magnetization direction of the magnetic material are in a same direction.

84. The body-insertable device system according to claim 80, wherein

the magnetic field generator is a second magnetic repulsive force generator which generates a magnetic repulsive force for the magnetic material;

and

the second magnetic repulsive force generator is placed above the liquid in the subject.

85. The body-insertable device system according to claim 84, wherein

the magnetic material has a specific magnetization direction;

center of gravity of the casing is set such that the magnetization direction and the liquid surface have an angular difference of 10 degrees or larger when the magnetic field generator is not generating magnetic field.

86. The body-insertable device system according to claim 85, wherein

a vertical component of the magnetization direction of the second magnetic repulsive force generator and a vertical component of the magnetization direction of the magnetic material are in an opposite direction.

87. The body-insertable device system according to claim 85, wherein a strength of a magnetic field generated by the second magnetic repulsive force generator at an arbitrary position on an arbitrary horizontal plane is smaller than a strength of a magnetic field generated by the second magnetic repulsive force generator around the arbitrary position on the arbitrary horizontal plane.

88. The body-insertable device system according to claim 84, wherein the magnetic material has a substantially cylindrical shape and includes magnetic poles at outer and inner peripheries of the cylindrical shape.

89. The body-insertable device system according to claim 79, wherein the specific gravity of the casing is larger than the specific gravity of the liquid.

90. The body-insertable device system according to claim 89, wherein the magnetic field generator is a fifth magnetic attracting force generator which generates a magnetic attracting force for the magnetic material;

and

the fifth magnetic attracting force generator is placed above the liquid in the subject in a vertical direction.

91. The body-insertable device system according to claim 89, wherein

the magnetic field generator is a third magnetic repulsive force generator which generates magnetic repulsive force for the magnetic material;

and

the third magnetic repulsive force generator is placed under the liquid in the subject in a vertical direction.

92. The body-insertable device system according to claim 79, wherein the vertical position controller includes a seventh magnetic field strength changing unit which changes a strength of a magnetic field generated by the magnetic field generator for the magnetic material.

93. The body-insertable device system according to claim 92, wherein

the magnetic material has a specific magnetization direction;

and

the drive unit includes a third posture controller which controls a posture of the casing in the liquid.

94. The body-insertable device system according to claim 92, wherein the drive unit includes a second horizontal position controller which controls a horizontal position of the casing in the liquid.

95. The body-insertable device system according to claim 94, wherein the second horizontal position controller is a fourth magnetic field generator horizontal position changing unit which changes horizontal position of the magnetic field generator.

96. The body-insertable device system according to claim 94, wherein

the magnetic material has a specific magnetization direction;

and

the drive unit includes a fourth posture controller which controls a posture of the casing in the liquid.

97. The body-insertable device system according to claim 96, wherein

the magnetic field generator includes the sixth magnetic attracting force generator;

and

the vertical position controller controls a vertical position of the casing by a magnetic attracting force.

98. The body-insertable device system according to claim 96, wherein

the magnetic field generator includes the fourth magnetic repulsive force generator;

and

the vertical position controller controls a vertical position of the casing by a magnetic repulsive force.

99. The body-insertable device system according to claim 92, wherein

the drive unit includes a position detector for detecting a position of the casing in the subject;

and

the seventh magnetic field strength changing unit changes a magnetic field generated by the magnetic field generator based on the position detection result.

100. The body-insertable device system according to claim 99, wherein the magnetic field generator is a sixth magnetic attracting force generator.

101. The body-insertable device system according to claim 92, wherein the seventh magnetic field strength changing unit vibrates a strength of a magnetic field generated by the magnetic field generator.

102. The body-insertable device system according to claim 79, wherein the specific gravity of the casing is substantially equal to the specific gravity of the liquid.

103. The body-insertable device system according to claim 19, further comprising a pattern drive unit which drives the drive unit based on a predetermined pattern.

104. The body-insertable device system according to claim 19, wherein the drive unit further includes

a magnetic field response detector which detects whether or not the casing has responded to a magnetic field generated by the magnetic field generator;

and

an eighth magnetic field strength changing unit which changes a strength of a magnetic field generated by the magnetic field generator based on the detection result of the magnetic field response detector.

105. The body-insertable device system according to claim 19, wherein the magnetic material is one of a permanent magnet, an electrical magnet, an electromagnetic material, and a battery.

106. The body-insertable device system according to claim 19, further comprising

an image combining unit which combines images taken by the imaging unit, wherein

the drive unit includes a position/posture detector which detects a position and posture of the casing in the subject;

and

the image combining unit combines the images taken by the imaging unit based on a result detected by the position/posture detector.

107. The body-insertable device system according to claim 19, wherein a region into which the casing is introduced is the stomach.

108. The body-insertable device system according to claim 19, wherein a region into which the casing is introduced is the large intestine.

109. An in-vivo observation method, comprising:

a casing introducing step of introducing a casing for obtaining an image into a subject;

a liquid introducing step of introducing liquid into the subject; and

a position/posture changing step of changing at least one of the position and posture of the casing in the liquid introduced in the casing introducing step.

110. The in-vivo observation method according to claim 109, wherein the casing introducing step is for introducing the casing having an specific gravity smaller than the specific gravity of the liquid into the subject.

111. The in-vivo observation method according to claim 109, wherein the casing introducing step is for introducing the casing having an specific gravity greater than the specific gravity of the liquid into the subject.

112. The in-vivo observation method according to claim 109, further comprising a specific gravity changing step of changing the specific gravity of the casing introduced into the subject with respect to the liquid.

113. The in-vivo observation method according to claim 109, wherein

the casing introducing step is for introducing the casing having a magnetic material into the subject;

and

the position/posture changing step includes a magnetic position/posture changing step of changing at least one of the position and posture of the casing by a magnetic field generated to the magnetic material.

114. The in-vivo observation method according to claim 113, wherein the magnetic position/posture changing step includes a magnetic field strength change step of changing strength of magnetic field generated to the magnetic material.

115. The in-vivo observation method according to claim 113, wherein the magnetic position/posture changing step includes a magnetic field direction change step of changing a direction of a magnetic field to the magnetic material.

116. The in-vivo observation method according to claim 115, wherein the casing introducing step is for introducing the casing having a specific gravity greater than the specific gravity of the liquid into the subject.

117. The in-vivo observation method according to claim 116, wherein the magnetic field direction change step includes a magnetic field generator placing step of placing a magnetic field generator for generating magnetic field to the magnetic material, above or under the subject in a vertical direction.

118. The in-vivo observation method according to claim 117, wherein the magnetic field generator placing step includes a magnetic field generator direction change step of changing a direction of the magnetic field generator.

119. The in-vivo observation method according to claim 117, wherein the magnetic field generator placing step includes a magnetic field generator horizontal position changing step of changing a horizontal position of the magnetic field generator.

120. The in-vivo observation method according to claim 116, wherein the magnetic field direction change step includes a magnetic field generator horizontal placing step of placing the magnetic field generator for generating a magnetic field for the magnetic material horizontally to the subject.

121. The in-vivo observation method according to claim 120, wherein the magnetic field generator horizontal placing step includes a magnetic field generator direction change step of changing a direction of the magnetic field generator.

122. The in-vivo observation method according to claim 120, wherein the magnetic field generator horizontal placing step includes a magnetic field generator position changing step of changing a vertical position of the magnetic field generator.

123. The in-vivo observation method according to claim 120, wherein the casing introducing step is for introducing the casing having a specific gravity smaller than a specific gravity of the liquid into the subject.

124. The in-vivo observation method according to claim 123, wherein the magnetic field direction change step includes a magnetic field generator placing step of placing the magnetic field generator for generating a magnetic field for the magnetic material, above or under the subject in a vertical direction.

125. The in-vivo observation method according to claim 113, wherein the magnetic position/posture changing step includes a casing horizontal position chanting step of changing a horizontal position of the casing in the liquid.

126. The in-vivo observation method according to claim 125, wherein the casing introducing step is for introducing the casing having a specific gravity smaller than at the specific gravity of the liquid into the subject.

127. The in-vivo observation method according to claim 125, wherein the casing horizontal position changing step includes a magnetic attracting force generating step of generating a magnetic attracting force for the magnetic material and changing a horizontal position of the casing.

128. The in-vivo observation method according to claim 127, wherein the casing introducing step is for introducing the casing having the magnetic material with the magnetization direction having an angular difference of 10 degrees or larger with respect to the liquid surface of the liquid into the subject when there is no generated magnetic field.

129. The in-vivo observation method according to claim 128, wherein the magnetic attracting force generating step includes a magnetic field generator placing step of placing a magnetic field generator for generating a magnetic field for the magnetic material above or under the subject, so that a vertical component of a magnetization direction of the magnetic field generator and a vertical component of a magnetization direction of the magnetic material become in a same direction.

130. The in-vivo observation method according to claim 128, wherein the magnetic attracting force generating step includes a magnetic field generator horizontal placing step of placing a magnetic field generator which generates a magnetic field for the magnetic material horizontally to the subject, so that a vertical component of a magnetization direction of the magnetic field generator and a vertical component of a magnetization direction of the magnetic material become in an opposite direction.

131. The in-vivo observation method according to claim 127, wherein the casing introducing step is for introducing the casing having the magnetic material with the magnetization direction substantially parallel to the liquid surface of the liquid into the subject when there is no generated magnetic field.

132. The in-vivo observation method according to claim 131, wherein the magnetic attracting force generating step includes a magnetic field generator placing step of placing a magnetic field generator which generates a magnetic field to the magnetic material above or under the subject in a vertical direction, so that the magnetization direction of the magnetic field generator and the liquid surface of the liquid become parallel.

133. The in-vivo observation method according to claim 131, wherein the magnetic attracting force generating step includes a magnetic field generator horizontal placing step of placing a magnetic field generator for generating a magnetic field to the magnetic material horizontally to the subject, so that the magnetization direction of the magnetic field generator and the liquid surface of the liquid become parallel.

134. The in-vivo observation method according to claim 127, wherein the magnetic attracting force generating step includes a horizontal position changing step of changing horizontal direction of a magnetic field generator which generates a magnetic attracting force for the magnetic material.

135. The in-vivo observation method according to claim 125, wherein the casing horizontal position changing step includes a magnetic repulsive force generating step of generating a magnetic repulsive force for the magnetic material and changing a horizontal direction of the casing.

136. The in-vivo observation method according to claim 135, wherein the casing introducing step is for introducing the casing having the magnetic material with the magnetization direction having an angular difference of 10 degrees or larger with respect to the liquid surface of the liquid into the subject when there is no generated magnetic field.

137. The in-vivo observation method according to claim 136, wherein the magnetic repulsive force generating step includes a magnetic field generator placing step of placing a magnetic field generator for generating a magnetic field for the magnetic material above or under the subject in a vertical direction, so that a vertical component of a magnetization direction of the magnetic field generator and a vertical component of a magnetization direction of the magnetic material become in an opposite direction.

138. The in-vivo observation method according to claim 136, wherein the magnetic repulsive force generating step includes a magnetic field generator horizontal placing step of placing a magnetic field generator which generates a magnetic field for the magnetic material horizontally to the subject, so that a vertical component of a magnetization direction of the magnetic field generator and a vertical component of a magnetization direction of the magnetic material become in a same direction.

139. The in-vivo observation method according to claim 135, wherein the magnetic repulsive force generating step includes a horizontal position changing step of changing a horizontal direction of a magnetic field generator which generates a magnetic field for the magnetic material.

140. The in-vivo observation method according to claim 125, wherein the casing horizontal position changing step includes a magnetic force switching/generating step of generating and switching magnetic attracting force and magnetic repulsive force for the magnetic material.

141. The in-vivo observation method according to claim 140, wherein the casing introducing step is for introducing the casing having the magnetic material with the magnetization direction having an angular difference of 10 degrees or larger with respect to the liquid surface of the liquid into the subject when there is no generated magnetic field.

142. The in-vivo observation method according to claim 141, wherein the magnetic force switching/generating step includes a magnetic field generator position changing step of changing vertical position of the magnetic field generator which generates a magnetic field for the magnetic material.

143. The in-vivo observation method according to claim 141, wherein the magnetic force switching/generating step includes a magnetic field generator direction changing step of changing direction of the magnetic field generator for generating a magnetic field to the magnetic material.

144. The in-vivo observation method according to claim 113, wherein the magnetic position/posture changing step includes a casing vertical position changing step of changing a vertical position of the casing in the liquid.

145. The in-vivo observation method according to claim 144, wherein the casing introducing step is for introducing the casing having a specific gravity smaller than the specific gravity of the liquid into the subject.

146. The in-vivo observation method according to claim 145, wherein the casing vertical position changing step includes a magnetic field generator placing step of placing the magnetic field generator for generating a magnetic attracting force for the magnetic material under the subject in a vertical direction.

147. The in-vivo observation method according to claim 145, wherein the casing vertical position changing step includes a magnetic field generator placing step of placing the magnetic field generator which generates a magnetic repulsive force to the magnetic material above the subject in a vertical direction.

148. The in-vivo observation method according to claim 144, wherein the casing introducing step is for introducing the casing with a specific gravity greater than the liquid.

149. The in-vivo observation method according to claim 145, wherein the casing vertical position changing step includes a magnetic field generator placing step of placing the magnetic field generator which generates a magnetic attracting force for the magnetic material above the subject in a vertical direction.

150. The in-vivo observation method according to claim 145, wherein the casing vertical position changing step includes a magnetic field generator placing step of placing the magnetic field generator which generates a magnetic attracting force for the magnetic material under the subject in a vertical direction.

151. The in-vivo observation method according to claim 144, wherein the casing vertical position changing step includes a magnetic field strength changing step of changing a position of the casing by changing strength of magnetic field applied to the magnetic material.

152. The in-vivo observation method according to claim 151, wherein the magnetic position/posture changing step further includes a casing posture changing step of changing a posture of the casing in the liquid.

153. The in-vivo observation method according to claim 144, wherein the magnetic position/posture changing step includes a casing horizontal position changing step of changing a horizontal position of the casing in the liquid after the casing vertical position changing step.

154. The in-vivo observation method according to claim 109, wherein

the casing introducing step is for introducing the casing into the subject through a mouth;

the liquid introducing step is for introducing the liquid into the subject through a mouth; and

the position/posture changing step is for changing at least one of the position and posture of the casing which has reached the inside of the stomach in the subject.

155. The in-vivo observation method according to claim 109, wherein

the casing introducing step is for introducing the casing into the subject through a mouth;

the liquid introducing step is for introducing the liquid into the subject through a mouth; and

the position/posture changing step is for changing at least one of the position and posture of the casing which has reached the inside of the large intestine in the subject.

156. The in-vivo observation method according to claim 109, wherein

the casing introducing step is for introducing the casing into the subject through an anus;

the liquid introducing step is for introducing the liquid into the subject through an anus; and

the position/posture changing step is for changing at least one of the position and posture of the casing which has reached the inside of the large intestine in the subject.

157. The in-vivo observation method according to claim 113, further comprising a body posture changing step of changing a body posture of the subject to which the casing and the liquid have been introduced.

158. The in-vivo observation method according to claim 113, further comprising a water level changing step of changing a water level of the liquid introduced into the subject.

159. The in-vivo observation method according to claim 113, wherein the casing introducing step is for introducing the casing having an imaging unit for imaging in the subject into the subject;

and includes an imaging unit approaching step of putting the imaging unit of the casing introduced into the subject close to an arbitrary stomach wall.

160. The in-vivo observation method according to claim 159, wherein the imaging unit approaching step is for putting the imaging unit of the casing close to an arbitrary stomach wall by changing the strength of a magnetic field generated for the magnetic material.

161. The in-vivo observation method according to claim 159, wherein the imaging unit approaching step is for putting the imaging unit of the casing close to an arbitrary stomach wall by changing a water level of the liquid introduced into the subject.