JP2001078976A - Biological magnetism measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use the means of data storage media of a system without waste by making it possible to vary data storage sites and storage method according to features during measurements. SOLUTION: In magnetic field measurements using a magnetic field sensor 10 comprising a SQUID 104, a data storage site changing part 166 changes a data storage site to a SRAM 168 when collection rate is fast and measuring time is short, and changes the data storage site to a SRAM 168 when the collection rate is slow and measuring time is long.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biomagnetism measuring apparatus for measuring magnetism generated in a living body and searching for a source of the magnetism.

[0002]

2. Description of the Related Art A biomagnetism measuring device is a device for measuring an electromagnetic phenomenon generated from a living body, that is, a change in a weak magnetic flux (magnetic field) caused by a change in the potential of the living body. The aim is to elucidate the functions and activities of the source. Since the biomagnetism measurement device measures biomagnetism, it is hardly affected by bones, and has unique characteristics such as detection of abnormalities in nerve activity.

As a typical signal diagram of a biomagnetic field obtained by this biomagnetic measuring apparatus, there is a magnetoencephalogram (MEG: MagnetEncephaloGram) based on a magnetic field generated from the brain.
The types of MEG can be broadly divided into external visual, auditory,
Responses to stimuli applied through sensations and the like can be divided into two types: evoked MEG, which captures as a magnetic field, and spontaneous MEG, which captures spontaneous brain reactions such as epileptic and alpha waves as magnetic fields. MCG triggered by biomagnetic measurement device
And about magnetic field measurement to obtain spontaneous MCG,
It is as follows.

In order to obtain an evoked MEG, first, a magnetic field in a state several seconds before application of a stimulus is measured. Next, a magnetic field induced by applying a stimulus to the subject is measured for about 1 second immediately after the stimulus, and in some cases for several seconds. By performing this series of measurement operations 100 times or more, a large amount of data is collected, averaged, and subjected to predetermined processing such as analysis of a magnetic field source, so that the induced MCG is displayed on a monitor or the like.

[0005] The total data collection time in the measurement of the induced MEG is about several minutes to several tens of minutes because data collection is performed 100 times or more as described above. In addition, one data collection time is on the order of msec, and a sampling frequency of about several kHz is required.

[0006] On the other hand, the spontaneous MEG measurement measures the spontaneous magnetic field generated from the subject as described above, so that the total data collection time may be 30 minutes or more. But,
The sampling frequency is about several hundred Hz.

That is, for example, in the case of a biomagnetism measuring apparatus having 100 channels with the number of channels (the number of sensors) and having an A / D converter capable of A / D conversion of 16 bits (2 bytes), 1
A 200-byte memory area is used for each data collection. When the measurement for obtaining the induced MEG is performed at a sampling frequency of 3 kHz, the biomagnetic measurement apparatus uses a memory area of 600 kbytes for 1 second and 36 Mbytes for 1 minute. On the other hand, when the measurement for obtaining the spontaneous MEG is performed at a sampling frequency of 300 Hz, the measurement uses a memory area of 60 kbytes for one second and 3.6 Mbytes for one minute.

[0008]

That is, the biomagnetic measurement for obtaining the induced MEG has a feature that the sampling rate is high but the sampling time is short. On the other hand, biomagnetic measurement for obtaining spontaneous MEG has a feature that the sampling rate is slow but the sampling time is long. Therefore, in order to store both data having different characteristics in the same data memory, a memory which has a high writing speed and can store a large amount of data is required. As a result, the device becomes large and the device becomes expensive.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes, for example, a storage destination of data, a storage method, and the like according to characteristics at the time of measurement, such as an induced MEG and a spontaneous MEG. It is an object of the present invention to realize a biomagnetism measurement apparatus that can change a collection method and can use assets of a data storage medium of a system such as a memory without waste.

The present invention has a detecting means for detecting magnetism from an object to be measured by a superconducting quantum interference device, and a plurality of storage media different in at least one of writing speed and capacity. A biomagnetism measuring apparatus comprising: a storage medium control unit that determines and stores a storage medium that stores the output of the detection unit.

In the biomagnetism measuring apparatus, it is preferable that the measurement mode sets at least one of an output rate of the detection means and a detection time.

According to such a configuration, the storage location of the output of the detection means is determined by the storage location control means based on at least one of the measurement mode, the detection rate, and the detection time. Therefore, the output of the detecting means can be appropriately stored according to the characteristics of the measurement, and the storage medium can be operated effectively. As a result, the size and cost of the device can be reduced.

[0013] The biomagnetism measuring apparatus may further include a display unit for generating image data related to the magnetism of the object to be measured based on an output of the detection unit and displaying the image data as an image, Means, wherein the storage destination control means, when an area is designated by the area designating means, the output of the detecting means relating to the designated area and a first area including its neighboring area And an output of the detection means for an area other than the first area may be stored in different storage media.

According to such a configuration, the first area including the area whose area is specified by the area specifying means and the area near the area.
The output of the detecting means relating to the region of interest and the output of the detecting means relating to the region other than the first region are stored in the storage destination determined by the storage destination control means based on at least one of the measurement mode, the detection rate, and the detection time. It is memorized. Therefore,
The data is stored in an appropriate storage medium, and the storage medium can be operated effectively. As a result, the size and cost of the device can be reduced.

[0015] The biomagnetism measuring apparatus may further comprise: display means for generating image data relating to the magnetism of the object to be measured based on the output of the detecting means and displaying the image data as an image; Point detecting means for detecting at least one of a point having a magnetism equal to or more than a value and a point having a predetermined change rate or more, and the storage destination control means, the point detection means, Are detected, the output of the detection means for the second area including the detected point and its neighboring area and the output of the detection means for the area other than the second area are stored in different storage media. A configuration characterized by storing is also possible.

According to such a configuration, at least one of a magnetic peak point, a point having a magnetism equal to or higher than a predetermined value, and a point having a predetermined rate of change or more, and at least one of the points and its neighboring area are included. The output of the detection means for the area 2 and the output of the detection means for the area other than the second area are stored in the storage destination determined by the storage destination control means based on at least one of the measurement mode, the detection rate, and the detection time. It is memorized. Therefore, the data is stored in an appropriate storage medium, and the storage medium can be operated effectively. As a result, the size and cost of the device can be reduced.

Further, in the above-described biomagnetism measuring device,
A display unit that generates image data related to the magnetism of the measurement target based on the output of the detection unit and displays the image data as an image, wherein the display unit includes the image and the storage medium determined by the storage destination control unit. May be configured to have a function of displaying the free space according to the detection time or the number of times of detection by the detection means.

According to such a configuration, the free space of the storage medium determined by the storage destination control means is displayed by the detection time or the number of times of detection by the detection means. You can know.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first to third embodiments of a biomagnetism measuring apparatus according to the present invention will be described with reference to the drawings, taking as an example the case of measuring a magnetic field (magnetism) generated from the brain.

(First Embodiment) FIG. 1 shows a schematic configuration of a biomagnetism measuring apparatus according to a first embodiment.

In FIG. 1, a magnetic field sensor 10 includes a superconducting quantum interference device (hereinafter, SQUID: SuperQUantum Interferen).
(ce device) 104 is a magnetic field detection device that detects a magnetic field generated from inside a living body. The figure shows the FLL circuit (Flux
Drive circuit 101 called Locked Loop circuit)
An example of a device for driving the SQUID 104 is shown. This magnetic field sensor 10 is a dewar (ultra low temperature vessel) cooled to -4.2 K (approximately -270 °) by liquid helium.
The dewar has a magnetic flux detecting coil 1
02, SQUID 104, negative feedback coil 106, amplifier 10
8, an integrator 109, a power supply 110 for supplying a bias current to the SQUID 104, and a resistor 111 for converting the output voltage V of the integrator into a negative feedback current.

The flux sensing coil 102 is a detector for detecting the magnetic flux [Phi ₁ generated from the brain 9 as a specimen is made of a superconducting material. Although FIG. 1 shows a single-turn coil, various types such as a primary gradient coil and a rectangular coil can be applied. SUQID 104 is a superconducting ring that responds to a weak magnetic field change by utilizing the quantum interference effect of magnetic flux. The SUQID 104 is supplied with a bias current from a power supply 110. Amplifier 108 and integrator 109 are
Amplifying means for amplifying the voltage signal from the QID 104.
The detection operation of the magnetic field sensor 10 by these components is as follows.

[0023] flux [Phi ₁ generated in the brain 9 penetrates the magnetic flux detecting coil 10, an electromotive force is generated magnetic flux detecting coil 10 by electromagnetic induction. Current flowing through the electromotive force in the coil 10 further induces measured magnetic flux [Phi _2. When measuring the magnetic flux [Phi ₂ penetrates the SUQID104, the SUQID104 is shifted from the superconducting state to the normal state, and outputs a voltage based on the magnetic flux [Phi ₂ to the amplifier 108. This voltage is amplified by the amplifier 108 and the integrator 109 and output as the voltage V.

[0024] The voltage V has a non-linear output that oscillates at substantially sinusoidal for measuring the magnetic flux [Phi _2. Therefore,
It is not useful to detect the biomagnetic field from the relationship between the measured magnetic flux [Phi ₂ and the voltage V. Therefore, SQUID10 is used by the FLL circuit.
4, the magnetic field sensor 10 drives the voltage V to the resistance 1
It converted to the negative feedback current by 11, a magnetic flux [Phi ₃ and the voltage V derived by the negative feedback current is negative feedback coil 106 flows into the
, The biomagnetic field is detected. This magnetic flux Φ ₃ is
The magnetic flux Φ ₂ cancels out the measured magnetic flux Φ ₂ , and the voltage V
_It has a _three- proportional relationship.

Then, the voltage signal V output from the magnetic field sensor 10 is sent to the amplifier circuit section 12.

The operating point of the magnetic field sensor 10 is selected, for example, by a method disclosed in Japanese Patent Application Laid-Open No. H11-2671, where the magnetic flux-voltage conversion efficiency is high.

FIG. 2 shows a modification of the biomagnetism measuring apparatus according to the first embodiment. This modification is a driving circuit 1
20 shows an example of a device for driving the SQUID 104. The magnetic field sensor 10 has a dewar (not shown), and a magnetic flux detection coil 10
2. SQUID 104, amplifier 108, A / D converter 122, DS
A power supply 110 that supplies a bias current to the P124, the D / A converter 126, and the SQUID 104, and a resistor 111 that converts the output voltage V of the integrator into a negative feedback current are provided. The same components as those of the biomagnetism measuring device shown in FIG. 1 are denoted by the same reference numerals.

A magnetic field sensor 1 of a modified example using the above components
The operation of detecting 0 is as follows.

The A / D converter 122 receives the voltage signal of the SQUID 104 amplified by the amplifier 108, converts it from an analog amount to a digital amount (A / D conversion), and sends it out to the DSP 124. The DSP 124 performs negative feedback on the digital signal subjected to the predetermined processing, and sends the digital signal to the D / A converter 126. The D / A converter 126 converts the digital signal into an analog signal again and sends the analog signal to the resistor 111. This analog signal is connected to the resistor 1
11, is converted into a negative feedback current, and the negative feedback coil 10
It flows into 6 to induce a magnetic flux [Phi _3. The magnetic flux Φ ₃ is, SP
It has a proportional relationship with the voltage output from the reference numeral 124.

Then, the voltage signal output from the magnetic field sensor 10 is sent to the data collection control unit 16.

The biomagnetism measuring apparatus according to this modification is used for data collection performed by a data collection unit 161 described later.
This is an effective device for changing the data collection rate. That is, when changing the rate, there is a method of directly changing the rate of A / D conversion, but this method is not preferable because the frequency of the magnetic field that the negative feedback loop can follow also changes. Therefore, according to the biomagnetism measuring device according to the modified example, it is possible to effectively convert the rate by dropping the digital signal output from the DSP 124 according to the modified example.

Hereinafter, description will be made again with reference to FIG.

The input unit 14 is an input device including a keyboard and a mouse. In the case of MEG measurement, the operator inputs from the input unit 14 a selection of a stimulated MEG measurement or a spontaneous MEG measurement, or a stimulation method or a measurement method in the triggered MEG.
Further, the data collection rate and the data collection destination can be changed by an instruction from the input unit 14.

The amplifier circuit 12 is an amplifier that receives a voltage signal from the magnetic field sensor 10, amplifies the voltage signal to a desired voltage, and sends out the amplified signal to the data acquisition controller 16.

The data collection control unit 16 includes the data collection unit 1
61, data processing unit 162, data collection rate switching unit 165, data storage destination switching unit 166, SRAM 168 and HD
The data storage unit 167 includes a data storage unit 167.

The data collecting section 161 is a data collecting means having an A / D converter, a DSP and the like. Data collection unit 161
Receives the voltage signal V output from the filter 13 and converts it from an analog amount to a digital amount (A / D conversion),
After performing a predetermined process, the data is sent to the data processing unit 162 and the data storage unit 167. The rate of data collection performed by the data collection unit 161 is performed at a rate switched under the control of a data collection rate switching unit 165 described later based on an input instruction from the operator. The switching of the rate can be realized by a configuration in which the data collection unit 161 further includes a switching device that switches the data capture rate.

The data processing unit 162 includes the data collection unit 16
The data received from 1 is subjected to interpolation processing for image generation and filter processing for noise removal.

The data collection rate switching unit 165 switches and sets the data collection rate executed by the data collection unit 161 based on the type of measurement input from the input unit 14 by the operator. The data collection rate is set in advance, for example, to 300 kHz / sec in the case of the induced MEG measurement and to 300 Hz / sec in the case of the spontaneous MEG measurement, and is automatically switched and set according to the selection of the measurement. The desired collection rate can be changed by a manual operation, and the previously set data collection rate can be reset.

The data storage destination switching unit 166 is connected to the input unit 1
Based on the type of measurement input from No. 4, switching control for switching the storage destination of the collected data to the SRAM 168 or the HD 169 is performed. That is, the data storage destination switching unit 166 sets the storage destination to the HD 169, which is a medium having a large capacity and a low data writing speed, in the case of a magnetic field measurement that requires a relatively long time and a low collection rate like a spontaneous MEG. Switch. On the other hand, in the case of a magnetic field measurement in which the acquisition rate is short in a relatively short time like the induced MEG, the storage destination is switched to the SRAM 168 which is a small-capacity but fast data writing medium. Note that it is also possible to switch to a desired storage destination by manual operation.

Further, as shown in a second embodiment to be described later, when the data writing speed to the HD 169 is lower than the collection rate, the data storage destination switching unit 166
Switch to SRAM 168 with fast writing speed and temporarily write collected data. Then, from among the once written data, the data is sequentially read from the oldest one, the collection destination is switched, and the data is written to the HD 169.

Further, as shown in a third embodiment to be described later, in the manual mode in which only the collected data designated by the operator is stored in the data storage unit 167, the data storage destination switching unit 166 is configured to store the collected data. Change the destination to SRAM168.

The data storage section 167 has the SRAM 168 and the HD 1
69, and stores the collected data received from the data collection unit 161 in the SRAM 168 or the HD 169 according to the switching control from the data storage destination switching unit 166.

The data analysis unit 18 receives data subjected to various processes from the data collection unit 14, and performs a magnetic field source analysis, image data generation, a mapping process between magnetic field information and image data, and the like based on the data.

The display unit 20 is a display device having a monitor such as a CRT, and based on image data received from the data analysis unit 18, biomagnetic data (for example, a magnetoencephalogram, a magnetocardiogram, or an analysis based on these). Is displayed.

Next, a procedure for obtaining an induced MEG or a spontaneous MEG by using the biomagnetic measuring apparatus configured as described above will be described. The measurement described below is performed by the data collection unit 161.
The data collected and processed in the normal mode are all stored in the data storage unit 167.

First, a trigger MEG or spontaneous M is input from the input unit 14.
Select EG.

The evoked MEG is a magnetoencephalogram in which a response after a certain delay time or a response before the stimulus externally applied to the stimulus applied through sight, hearing, sensation or the like is captured as a magnetic field. The measurement for obtaining the induced MEG has a feature that the sampling rate is fast and the sampling time is short. On the other hand, spontaneous MEG is a magnetoencephalogram in which spontaneous reactions of the brain such as epileptic waves and alpha waves are captured as a magnetic field. Biomagnetic measurement for obtaining spontaneous MEG has a characteristic that the sampling rate is slow but the sampling time is long.

Next, magnetic field measurement is performed by a predetermined operation. At this time, if the spontaneous MEG measurement is selected, the data is automatically stored in the SRAM 168 in the data storage unit 167. In addition, when the induced MEG measurement is selected, the data is automatically stored in the HD 169. Regardless of the type of measurement, if data exists in the SRAM 168, the data is automatically stored in the HD 169 until the next measurement.

The operator simultaneously writes the data written in the data storage unit 167 into the display unit 20.
Can be observed as a waveform displayed on the display. Also,
It is also possible to read out the collected data that has already been measured and stored in the data storage unit 167 by a reproducing unit (not shown) and observe it.

According to such a configuration, the data storage destination switching unit 166 determines the collection data storage destination based on the type of measurement, that is, the data collection rate and the data collection time. Therefore, the collected data can be appropriately stored according to the characteristics of the measurement, and the data storage medium can be operated effectively. As a result, the size and cost of the device can be reduced.

(Second Embodiment) In the first embodiment, the storage destination of the collected data is automatically switched according to the type of measurement in the normal mode. However, the writing speed of the collected data to the HD 169 may be lower than the collection rate due to an arbitrary setting change of the operator. In this case, even if the measurement requires a large-capacity memory, it is not appropriate that the first storage destination is the HD169.

The operation of the biomagnetism measuring apparatus according to the present invention in the case where the writing speed of the collected data to the HD 169 is slower than the collection rate will be described as a second embodiment.

When the collection rate set by the operator in advance is faster than the data writing speed to the HD 169, the data storage destination switching unit 166 controls the data storage destination even if the spontaneous MEG is selected. SRAM 168
Switch to Then, while temporarily storing the data in the SRAM 168, the data stored in the SRAM 168 is sequentially read from the oldest one, and the data is written by switching the storage destination to the HD 169.

According to such a configuration, once the data storage destination is the SRAM 168, and the data is sequentially read from the old data and stored again in the HD 169, the time for writing the collected data to the storage medium is measured at a time slower than the collection rate. Even if there is, appropriate storage of collected data can be realized.
As a result, the size and cost of the device can be reduced.

(Third Embodiment) In the first and second embodiments, the case where the storage destination is switched according to the type of measurement in the normal mode in which all the measured biomagnetic fields are stored has been described.

On the other hand, in the third embodiment, the display unit 2
A description will be given of the case of the manual mode in which the data storage destination of the biomagnetism displayed on the monitor No. 0 is switched between a predetermined region including the region of interest specified by the manual operation and another region.

The schematic configuration of the biomagnetism measuring apparatus according to the third embodiment is the same as that shown in FIG.

When measuring MEG data in the manual mode, the collection rate of the data collection unit 161 is set to several kHz, regardless of the type of measurement. The collected data is stored in the HD 169 in principle.

FIG. 3 is a magnetoencephalogram showing a waveform example of spontaneous MEG data obtained by measuring a sudden signal of epilepsy. The waveform of the MEG data obtained by measuring the arrhythmia is as shown in this example.
The waveform of this magnetoencephalogram has time (S) on the horizontal axis and magnetic field (p
T) is displayed on the monitor of the display unit 20 in real time during measurement.

[0060] Sections A and B in the figure indicate regions of interest selected by the operator. The region of interest can be arbitrarily designated by assigning a click operation of the input unit 14 with a mouse or the like.

For example, it is assumed that an interesting waveform (a waveform in the section A) appears in the waveform of FIG. 3 displayed on the display unit 20 in the measurement of a sudden signal such as epilepsy or arrhythmia in the manual mode. At this time, the operator specifies the section by the manual operation described above.

Then, the data storage destination switching unit 166
The storage destination of the collected data is switched from the HD 169 to the SRAM 168 with a high writing speed.

The data collection section 161 stores the collected data including the section A in FIG. 3 which is the operator's area of interest and the waveforms of the predetermined area before and after the section A in the SRAM in the data storage section 167.
168. The length of the predetermined region before and after the region of interest is set in advance and can be arbitrarily changed.

The SRAM 168 stores the collected data received from the data collection unit 161. At this time, generally
Since the memory area of the SRAM is not large, it is preferable to display data that can be stored in the SRAM 168 by the number of bytes and the remaining time. Simultaneously with the measurement, SRAM 168
Sequentially read the collected data stored in
A configuration in which data is written to the HD 169 having a large capacity may be used.

When the collected data including the section A and the waveforms of the predetermined area before and after the section A is stored in the SRAM 168, the data storage destination switching unit 166 switches the data storage destination to the HD 169. Then, when the section B is displayed, the collected data is partially stored in the SRAM 168 by a similar operation.

According to such a configuration, collected data relating to a region of interest and a predetermined region before and after the region of interest is several kilohertz.
Data collection at a high collection rate of about z and storage at a high writing speed are possible, and collected data relating to other areas is also stored in the HD. Therefore, appropriate data can be stored in real time, and memory resources can be operated without waste. As a result, the size and cost of the device can be reduced.

The present invention has been described based on the first to third embodiments. However, the present invention is not limited to the above-described embodiments. For example, as shown in the following (1) to (3), Various modifications can be made without changing the gist.

(1) In the first to third embodiments,
The description has been given by taking the measurement for obtaining the magnetoencephalogram as an example. However, it is needless to say that the biomagnetic measurement device can measure a magnetic field for various human body parts such as a heart, a lung, and a muscle. Therefore, the biomagnetism measuring apparatus according to the present invention can obtain the same effect in magnetic field measurement for these parts.

(2) In the third embodiment, the predetermined region based on the region of interest specified by the manual operation of the operator is stored in the SRAM 168.
On the other hand, from the general fact that the waveform suddenly changes when epilepsy or arrhythmia occurs, the peak point C and the point D where the change rate is sharp in the waveform shown in FIG. 4 are automatically detected. The detection unit may be further configured to store a predetermined area including the front and rear portions of these locations in the SRAM 168.

According to such a configuration, it is possible to provide a biomagnetic measuring apparatus in which measurement is further automated, and it is possible to improve workability.

(3) In the third embodiment, a region of interest is specified for a waveform displayed on the display unit 20 by manual operation, and a predetermined region based on the region of interest is specified.
The configuration is such that the data is stored in the SRAM 168. However, the designation of the region of interest is not limited to the waveform of the magnetoencephalogram and the like. For example, the region of interest is designated with respect to the isomagnetic field map of the heart, and the SRAM 1 such as a predetermined region including the region near the region of interest is designated.
68.

[0072]

According to the present invention, the storage destination of collected data can be distinguished depending on the type of measurement. Further, only the designated region of interest can be stored in an appropriate storage medium. As a result, appropriate storage of collected data can be realized, and downsizing and low cost of the apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a biomagnetism measuring apparatus according to a first embodiment.

FIG. 2 is a diagram showing a modified example of the biomagnetism measurement device according to the first embodiment.

FIG. 3 is a magnetoencephalogram showing a waveform of spontaneous MEG data.

FIG. 4 is a magnetoencephalogram showing a waveform of spontaneous MEG data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Brain 10 ... Magnetic field sensor 12 ... Amplification circuit part 14 ... Input part 16 ... Data collection part 18 ... Data analysis part 20 ... Display part 101 ... Drive circuit 102 ... Magnetic flux detection coil 104 ... SQUID104 106 ... Negative feedback coil 108 ... Amplifier 109 integrator 110 power supply 111 resistor 120 drive circuit 122 A / D converter 124 DSP 126 D / A converter 161 data collection unit 162 data processing unit 165 data collection rate switching unit 166 Data collection destination switching unit 167 ... Data storage unit 168 ... SRAM 169 ... HD (hard disk)

Claims (5)

[Claims] 1. A detecting means for detecting magnetism from an object to be measured by a superconducting quantum interference device, and a plurality of storage media different in at least one of writing speed and capacity, wherein the detecting is performed based on a measuring mode. And a storage destination control means for determining and storing a storage medium for storing the output of the means. 2. The biomagnetism measurement apparatus according to claim 1, wherein the measurement mode sets at least one of an output rate and a detection time of the detection unit. A display unit configured to generate image data related to magnetism of the measurement target based on an output of the detection unit and display the image data as an image; and an area specification unit that specifies an area for the image. When an area is specified by the area specifying means, the storage destination control means outputs the output of the detecting means relating to the specified area and the first area including its neighboring area to the area other than the first area. The biomagnetic measurement apparatus according to claim 1, wherein the output is stored in a storage medium different from an output of the detection unit regarding an area. 4. A display means for generating image data relating to magnetism of a measurement object based on an output of the detection means and displaying the image data as an image, wherein the image has a magnetic peak point and a point having magnetism of a predetermined value or more. And a point detection unit that detects at least one of the points having a predetermined change rate or more, wherein the storage destination control unit detects when any of the points is detected by the point detection unit. Storing in a different storage medium the output of the detection means for a second area including the detected point and its neighboring area and the output of the detection means for an area other than the second area. The biomagnetic measurement device according to claim 1 or 2, wherein 5. A display device, further comprising: display means for generating image data relating to magnetism of a measurement object based on an output of the detection means and displaying the image data as an image, wherein the display means is provided together with the image by the storage destination control means. The biomagnetism measurement apparatus according to any one of claims 1 to 4, further comprising a function of displaying the determined free space of the storage medium based on the detection time or the number of times of detection by the detection unit.