JP4803368B2 - Biomagnetometer for small animals - Google Patents

Description

  The present invention relates to a biomagnetism measuring apparatus for small animals, and more particularly, to a biomagnetism measuring apparatus for small animals having a configuration suitable for measuring the magnetocardiogram and cerebral magnetic field of a small animal such as a mouse.

2. Description of the Related Art Conventionally, a biomagnetic measurement system that measures a magnetocardiogram by bringing a superconducting sensor cooled with liquid helium in a dewar close to the chest of a person sleeping in a bed is known (see, for example, Patent Document 1). .)
Also, a magnetocardiograph is known in which a superconducting sensor cooled with liquid helium in a dewar is installed in a bed and the magnetocardiogram of a person sleeping on the bed is measured from the back side (for example, Patent Document 2). reference.).
JP 2002-57377 A JP 2003-310565 A

The conventional biomagnetism measurement system and magnetocardiogram measurement apparatus have a large-scale configuration having a magnetic / radio wave shield room that encloses a whole from a bed where a person sleeps to a dewar.
However, such a large-scale configuration is not suitable for use in measuring the magnetocardiogram or magnetoencephalogram of a small animal such as a mouse.
Accordingly, an object of the present invention is to provide a biomagnetism measuring apparatus for small animals having a configuration suitable for measuring the magnetocardiogram and brain magnetism of small animals such as mice.

In a first aspect, the present invention relates to a small animal room surrounded by a magnetic / radio wave shield and capable of accommodating small animals, a dewar room installed on the small animal room, a dewar installed in the dewar room, A sensor tube having an outer diameter of 50 mm or less that hangs down from the dewar and protrudes from the floor of the dewar chamber through the ceiling of the small animal chamber to the center of the small animal chamber, and a superconducting magnet installed at the lower end of the sensor tube A biomagnetism measuring apparatus for small animals, comprising a sensor.
In the above configuration, the “small animal” means an animal having a weight of 7 kg or less.
In the biomagnetism measuring apparatus for small animals according to the first aspect, the small animal room for accommodating the small animal and the dewar room for accommodating the dewar are separated, and the small animal room is surrounded by a magnetic / radio wave shield separately from the dewar room. Then, the sensor cylinder is suspended from the dewar chamber, and the lower end portion of the sensor cylinder containing the superconducting magnetic sensor is projected around the center of the small animal chamber. As a result, a magnetic / radio wave shield is required to have a minimum configuration, and no noise source (eg, a magnetic member) is required in the small animal room. It becomes possible to measure. The reason why the outer diameter of the sensor tube is 50 mm or less is to prevent noise from wrapping around through the hole through which the sensor tube passes.

In a second aspect, the present invention provides the small animal biomagnetism measuring apparatus according to the first aspect, wherein the dewar chamber is surrounded by a simpler magnetic / radio wave shield than the small animal chamber. A biomagnetism measuring apparatus is provided.
In the biomagnetism measuring apparatus for small animals according to the second aspect described above, the dewar room is surrounded by a simple magnetic / radio wave shield from the small animal room. Can be small.

In a third aspect, the present invention provides a biomagnetism measuring apparatus for small animals according to the first or second aspect, using a nonmagnetic material for placing a small animal on the top surface and moving it up, down, front, back, left and right. There is provided a biomagnetism measuring apparatus for small animals, characterized in that small animal position moving means is installed in the small animal room.
In the biomagnetism measuring apparatus for small animals according to the third aspect, the small animal can be moved and aligned with the superconducting magnetic sensor. The reason for using a non-magnetic material is to prevent a noise source.

In a fourth aspect, the present invention provides the biomagnetometry apparatus for small animals according to any one of the first to third aspects, wherein the sensor tube has flexibility and protrudes into the small animal chamber. There is provided a biomagnetism measuring apparatus for a small animal, characterized in that a sensor position moving means made of a nonmagnetic material for moving the position of the superconducting sensor by bending the sensor tube is installed in the small animal chamber.
In the biomagnetism measuring apparatus for small animals according to the fourth aspect, the superconducting magnetic sensor can be moved and aligned with the small animals. The reason for using a non-magnetic material is to prevent a noise source.

  According to the biomagnetism measuring apparatus for small animals of the present invention, a magnetic / radio wave shield is required to have a minimum configuration, and a noise source (for example, a magnetic member) need not be present in the small animal room. The magnetocardiogram and magnetoencephalogram of a small animal can be measured suitably.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a configuration diagram illustrating a biomagnetism measuring apparatus 100 for small animals according to a first embodiment of the present invention.
This biomagnetism measuring apparatus 100 for small animals is surrounded by a magnetic / radio wave shield 1a and can accommodate a small animal A, a dewar room 2 installed on the small animal room 1, and a dewar room 2. The dewar 3, the sensor tube 4 having an outer diameter of 35 mm projecting from the floor of the dewar chamber 2 through the ceiling of the small animal chamber 1 to the center of the small animal chamber 1, and the lower end of the sensor tube 4 A superconducting magnetic sensor 5 installed, a base 15 installed under the small animal room 1 and containing an electronic circuit for driving the superconducting sensor 5, and a signal from the electronic circuit are processed to extract biomagnetic information. And an information processing apparatus 20.

The magnetic / radio wave shield 1a of the small animal room 1 is made of a laminate of two layers of permalloy and one layer of copper plate.
The dewar chamber 2 is also surrounded by a magnetic / radio wave shield made of a laminate of one layer of permalloy and one layer of aluminum plate.

  The sensor tube 4 is made of a fluororesin and has flexibility.

  On the floor in the small animal room 1, the Z stage 6 z that moves up and down by turning the knob 61, the X stage 6 x that moves back and forth by turning the knob 62, and the left and right by turning the knob 63. A small animal moving table 6 having a Y stage 6y is installed. The small animal moving table 6 is made of a nonmagnetic material such as plastic or brass.

On the upper wall surface in the small animal room 1, an X frame 7x that moves back and forth by turning the knob 71, a Y frame 7y that moves to the left and right by turning the knob 72, and a sensor tube 4 attached to the Y frame 7y. A sensor moving mechanism 7 having a constraining plate 70 that constrains the xy in the xy direction is installed. The sensor moving mechanism 7 is made of a nonmagnetic material such as plastic or brass.
The X frame 7x and the Y frame 7y are only frames. This is because the visual field of the cameras 13 and 14 to be described later is not hindered.
As shown in FIG. 2, when the restraint plate 70 is moved, the sensor tube 4 is bent and the position of the superconducting magnetic sensor 5 can be moved.

The small animal room 1 has a left door 8L and a right door 8R that are double-split.
The right door 8R is provided with a notch 9 that is open on the side of the joint with the left door 8L. By passing the anesthetic liquid tube 10 through the cutout hole 9 and closing the left door 8L and the right door 8R to measure the magnetocardiogram and cerebral magnetic field of the small animal A, the anesthetic is injected from the anesthetic liquid injection device placed outside the small animal room 1. The liquid can be injected into the small animal A.

  When the temperature control bed 11 is used, by passing the hot water tube 12 through the cutout hole 9, the left door 8L and the right door 8R are closed and the magnetocardiogram and magnetoencephalogram of the small animal A are measured. Warm water can be supplied to and discharged from the temperature control bed 11 from the hot water circulation device placed in the room.

  In addition, you may open the notch hole 9 in the other side (for example, lower side) of the right door 8R. Further, the cutout hole 9 may be provided in the left door 8L instead of the right door 8R, or the cutout hole 9 may be provided in the left door 8L in addition to the right door 8R.

At least two places (preferably four places) sandwiching the sensor tube 4 on the ceiling of the small animal room 1, cameras 13 and 15 for photographing the inside of the small animal room 1 and LEDs 14 and 16 for illumination are installed. .
While the left door 8L and the right door 8R are closed and the magnetocardiogram and the magnetoencephalogram of the small animal A are being measured, the information processing apparatus 20 intermittently photographs the inside of the small animal room 1 and analyzes the obtained image. The position of the superconducting magnetic sensor 5 in the small animal room 1 (the position of the lower end of the sensor tube 4) is detected, recorded, and displayed on the display.

  Note that the LEDs 14 and 16 for illumination may be omitted. In this case, the left door 8L and the right door 8R are opened, and the inside of the small animal room 1 is photographed with illumination from the outside.

  For example, it can be used to measure a magnetic field emitted from a small animal such as a mouse.

1 is a front view illustrating a biomagnetism measuring apparatus for small animals according to Example 1. FIG. It is a partial front view which shows the state which moved the position of the superconducting magnetic sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Small animal room 1a Magnetic / radio wave shield 2 Dewar room 3 Dewar 4 Sensor tube 5 Superconducting magnetic sensor 6 Small animal moving table 7 Sensor moving mechanism 8L, 8R Door 9 Notch 10 Anesthetic liquid tube 11 Temperature control bed 12 Hot water tube 100 For small animals Biomagnetic measurement device A Small animal

Claims (3)

A small animal room surrounded by a magnetic / radio wave shield and capable of accommodating small animals; a dewar room installed on the small animal room; a dewar installed in the dewar room; and a floor of the dewar room hanging from the dewar A flexible sensor tube with an outer diameter of 50 mm or less that protrudes through the ceiling of the small animal room to the center of the small animal room, a superconducting magnetic sensor installed at the lower end of the sensor tube, and the small animal A biomagnetism for small animals , comprising: a sensor position moving means made of a nonmagnetic material for moving the position of the superconducting sensor by bending the sensor tube that is installed in the room and protrudes into the small animal room. measuring device. 2. The biomagnetism measuring apparatus for small animals according to claim 1, wherein the dewar chamber is surrounded by a simpler magnetic / radio wave shield than the small animal chamber. 3. The biomagnetism measuring apparatus for small animals according to claim 1 or 2, wherein a small animal position moving means by a non-magnetic material for placing the small animal on the upper surface and moving up, down, front, back, left and right is installed in the small animal room. A biomagnetism measuring apparatus for small animals characterized by the above.

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