JP4992054B2 - 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 provides a small animal room surrounded by a magnetic / radio wave shield and capable of accommodating small animals, a dewar room installed under the small animal room, a dewar installed in the dewar room, A sensor tube having an outer diameter of 50 mm or less projecting upward from the dewar and projecting from the ceiling of the dewar chamber through the floor of the small animal chamber to the center of the small animal chamber, and superconductivity installed at the upper end of the sensor tube Provided is a biomagnetism measuring apparatus for small animals, comprising a magnetic sensor and a bed having a small animal placement surface 5 mm or less above the upper end of the sensor tube.
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 protrudes upward from the dewar chamber, and the upper end portion of the sensor cylinder containing the superconducting magnetic sensor protrudes 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 relates to a small animal biomagnetic measurement apparatus according to the first or second aspect, wherein the bed is moved by a nonmagnetic material for moving the bed in at least one of the front-rear direction and the left-right direction. There is provided a biomagnetism measuring apparatus for small animals, characterized in that means are installed in the small animal chamber.
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.

  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.
The 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 under the small animal room 1, and a dewar room 2. Dewar 3, sensor tube 4 having an outer diameter of 25 mm projecting upward from dewar 3, projecting from the ceiling of dewar chamber 2 through the floor of small animal chamber 1 to the center of small animal chamber 1, and the upper end of sensor tube 4 And an information processing apparatus 20 that includes an electronic circuit that drives the superconducting sensor 5 and that processes signals from the electronic circuit and extracts biomagnetic information.

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.

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 having a Y stage 6y is installed. The small animal platform is made of a non-magnetic material such as plastic or brass.
A temperature control bed 11 is placed on the Y stage 6y.

There is a square hole of 100 mm × 100 mm in the center of the temperature control bed 11, and the upper end portion of the sensor tube 4 enters the square hole.
On the temperature control bed 11, a sheet 13 having a thickness of 1 mm for placing the small animal A is laid.
The distance from the upper end of the sensor tube 4 to the upper surface of the sheet 13 is 5 mm or less, preferably about 2 mm, in order to detect a weak biomagnetic field.

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.

  In addition, by passing the hot water tube 12 through the cutout hole 9, the left door 8L and the right door 8R are closed to measure the magnetocardiogram and magnetoencephalogram of the small animal A, and the temperature is adjusted from the hot water circulation device placed outside the small animal room 1. Hot water can be supplied to and discharged from the bed 11.

  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.

  On the ceiling of the small animal room 1, a camera 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 measured, the information processing apparatus 20 intermittently captures, records, and displays the inside of the small animal room 1 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.

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 6x X stage 6y Y stage 6z Z stage 8L, 8R Door 9 Notch 10 Anesthetic liquid tube 11 Temperature control bed 12 Hot water tube 100 Small animal Biomagnetism Measuring 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 under the small animal room; a dewar installed in the dewar room; A sensor tube having an outer diameter of 50 mm or less protruding from the ceiling through the floor of the small animal room to the center of the small animal room, a superconducting magnetic sensor installed at the upper end of the sensor tube, and an upper end of the sensor tube And a bed having a small animal placement surface 5 mm or less above , wherein the magnetocardiogram of the small animal placed in a prone posture on the small animal placement surface can be measured from the chest side of the small animal. Biomagnetic measurement device. The biomagnetometer for small animals according to claim 1, wherein at least one of an anesthetic solution tube or a hot water tube is opened from the outside to the inside with the door of the small animal chamber closed. A biomagnetism measuring apparatus for small animals , wherein a cutout hole is provided in the door . The biomagnetometer for small animals according to claim 1 or 2, wherein a bed moving means made of a non-magnetic material for moving the bed in at least one of the front-rear direction and the left-right direction is installed in the small animal chamber , The bed is provided with a hole through which the upper end of the sensor tube can enter so that the bed can be moved and the small animal mounting surface can be installed 5 mm or less above the upper end of the sensor tube. A biomagnetism measuring device for small animals.

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