JPS5950347A - Method for scanning characteristic magnetic field in nuclear magnetic resonance image method - Google Patents

Abstract

PURPOSE:To perform simply and rapidly a concrete scanning of a rod-shaped characteristic magnetic field by synthesizing a static magnetic field H0 and a magnetic field causing by a coil group to generate a characteristic magnetic field DELTAHs, and superimposing and varying a scanning magnetic field component of the magnetic field due to the coil group governing the magnetic field strength variation of the field DELTAHs. CONSTITUTION:If a scanning parallel filament coil generating almost uniform magnetic field is provided and the ampere number NsIs is set, the magnetic field of the scanning coil turns to the (x) axis direction and has almost no magnetic field component in the (x) axis direction. If the scanning magnetic field Hs is impressed superimoposingly in the (x) direction, the zero magnetic field point moves to a position Xs on the (x) axis, and the rod-shaped characteristic magnetic field obtained at the time is shown by an equation I . The center of the rod-shaped characteristic magnetic field DELTAHs moves to the position Xs, and it is found that the moved amount, namely the scanned amount can be varied in proportion to the current Is of the scanning magnetic field generating coil from the equation I . Also with respect to the (y) axis direction, if a uniform magnetic field for (y) direction scanning is impressd superimposingly by a (y)-direction scanning coil, the scanning can be performed extremely simply and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for scanning a characteristic magnetic field in nuclear magnetic resonance imaging, which visualizes and measures information inside a measured object using a nuclear magnetic resonance phenomenon. )
Nuclear magnetic materials inside the object to be measured, such as H,
F, 'Na +, K, 'Mg, O'.

In order to extract information about P, etc. to the outside and convert it into an image, we apply a full magnetic field consisting of a static magnetic field that is different from the surrounding area to the part to be measured, and the information of only the part to be measured is In particular, the present invention is concerned with a method for scanning a characteristic magnetic field for a magnetic field, and in particular, it is possible to scan a characteristic magnetic field by a simple and practical wide-air scanning using a small and lightweight device.

In the conventional scanning method of this rod characteristic (a-field), for example, in the scanning method related to the characteristic magnetic field generation method described in Japanese Unexamined Patent Publication No. 54-133192 proposed by the present inventors, In order to obtain the nuclear magnetic resonance 1゛H information in the rod-like region, we use the parallel striation group to obtain the rod-like characteristic magnetic field, that is,
A bar-shaped focal magnetic field was generated, and the characteristic magnetic field was scanned by switching the current distribution in the group of parallel lines. However, such a conventional scanning method has the disadvantage that the configuration of the current coil is complicated, and a switching circuit is required to completely switch the current distribution, making its driving complicated.

1. In such a conventional characteristic 411 field scanning method,
The characteristic magnetic field ΔHs is a bar-shaped focal magnetic field in which the magnetic field has a cylindrical shape in the region of interest and extends in the direction of the static magnetic field H8, or a spherical or ellipsoidal shape having a closed curved surface in the shape of a sphere or an ellipsoid. Body-shaped focal magnetic fields and focal magnetic fields that open toward the periphery in a bell-like or drum-like shape are known, but the scanning of the conventionally known % magnetic field is complicated. As mentioned above.

The object of the present invention is to eliminate the above-mentioned conventional drawbacks and, in particular, to provide a specific scanning of a bar-shaped focal magnetic field such that information in the bar-shaped region 1 is taken at once and scanning enables high-speed imaging. It is an object of the present invention to provide a characteristic magnetic field scanning method in nuclear magnetic resonance imaging that can be performed simply and quickly.

That is, the characteristic magnetic field travel method of the present invention uses a static magnetic field (Ho
) In order to determine the internal information of the object to be measured inside the magnetic resonance phenomenon by the nuclear magnetic resonance phenomenon, a characteristic magnetic field is created by combining the static magnetic field (■ (.) and the magnetic field of the coil m hair or the group of magnets. (ΔH8), and its characteristic magnetic field (ΔH
s) Magnetic field strength change By superimposing and changing the scanning magnetic field in the direction of the predetermined magnetic field component of (1!
) is characterized by moving the center by approximately %.

Therefore, the bar-shaped focal magnetic field useful for nuclear magnetic resonance imaging is
A bar-shaped focal point in the direction of superimposed application! A group of parallel wires that are arranged parallel to the direction of the uniform static magnetic field H6 to form a magnetic field to differentially form a magnetic field, or a group of parallel wires that are arranged orthogonally in combination so that the magnetic field components in the above directions cancel each other out. It can be generated by superimposing a homostatic magnetic field in the above-mentioned direction onto the magnetic field formed by the two differential coil pairs, and the features of the bar-shaped focal magnetic field formation in this manner are as follows: At the center of the formed bar-shaped focal magnetic field, the shape of seven I
A: The force of the magnetic field generated by the differential parallel wire group holding the VC or the pair of horizontally orthogonal moving coils becomes zero, and the magnetic field strength increases linearly from the center. and that the direction of the magnetic field is directly related to the direction of the static magnetic field H8.Therefore, the rod-shaped block formed by combining all vectors of both magnetic fields (radial direction of the magnetic field at one point) The change in magnetic field strength at is a square curve.
He is fully recovered.

However, what about the bar-shaped focus (lB, field scanning method) that has such properties?
jl Eclipse I■.

If a uniform traveling magnetic field oriented in the direction of
In the perpendicular plane V, the zero magnetic field point where the magnetic j component in the direction along the plane is zero moves to another position according to the magnitude of the superimposed scanning magnetic field and the direction in the plane, =j, the magnetic field is formed in a closed form around the zero magnetic field point of the new position fJ:,
Therefore, the bar-shaped focal magnetic field can be arbitrarily scanned within the above-mentioned plane orthogonal to the static magnetic field H8.

Next, to explain the specific implementation of the characteristic magnetic field scanning method according to the present invention described above, for the sake of simplicity, an example will be explained in which a characteristic magnetic field is generated by four filaments of ten bamboos. .

First, as a first example, we will explain the difference in the case where a bar-shaped characteristic magnetic field formed by a three-domain line is linearly scanned by superimposing a scanning magnet J8 by a uniform magnetic field residual coil. FIG. 1 shows the manner in which a bar-shaped characteristic magnetic field is generated by four dynamic parallel filaments. In the illustrated mode of occurrence,
The uniform static magnetic field H8 applied from the outside is
If they are superimposed in the axial direction, and in that case, the amperage of each of the four parallel lines is equal, the magnetic field contour lines close approximately in a circle around the coordinate origin, and a bar-shaped characteristic magnetic field that extends in the Z-axis direction, that is, A so-called bar-shaped focal magnetic field is formed.

Ru. The mode of each magnetic field due to the four parallel filaments in that case is shown by arrows in the figure. The magnetic field that bends has only magnetic field components in the Xy plane, that is, an X magnetic field component and a y magnetic field component, and does not have magnetic field components in the biaxial directions. The bar-shaped characteristic magnetic field generated in the manner shown in Figure 1 and its respective magnetic field components (
-11 respectively, λ is expressed by the following equation, in particular equation (4), where g is a constant determined by the parallel filament spacing and the ampere recirculation set t.

Therefore, the first
In addition to the configuration shown in the figure, as shown in Figure 2, a parallel wire coil for scanning or a Helmholtz coil for generating a nearly uniform magnetic field is additionally arranged, and its amperage is When NI is set, the magnetic field generated by the scanning coil is oriented in the X-axis direction in the configuration shown, and the magnetic field component is oriented L in the Z-axis direction.
/i almost never exists, and is expressed by the following formula.

ll5=hXNs Engineering. (5) Here, hx is a constant determined by the dimensions of the X-direction scanning coil, etc. Therefore, when the scanning magnetic field Hs is applied in a superimposed manner in the X direction, the zero magnetic field point moves to the position Xs on the X axis, and the resulting bar-shaped feature (the magnetic field is expressed by the following equation).

2 From this equation (7), the center of the bar-like characteristic magnetic field ΔHs is at the position
It can be seen that it has moved to s. Moreover, it can be seen from equation (6) that the movement %, that is, the scanning distance, can be changed in proportion to the current of the scanning magnetic field generating coil.

Further, in the y-axis direction, if a uniform magnetic field for y-direction scanning is applied in a superimposed manner by a y-direction scanning coil, scanning can be performed extremely simply and easily in the same manner as described above. Note that when scanning is performed in an intermediate direction on the XY plane, the scanning J old 111. In the following explanation, for convenience, we have described the case where a differential parallel wire group is used as the middle stage of generating a bar-shaped characteristic magnetic field, but this example is only applicable. The combination of differential coil groups, k! The same applies to the case where the entire bar-shaped characteristic magnetic field generated by a combination of ITII-like magnet groups is scanned.

Next, as a second example, the mode of characteristic magnetic field scanning will be described in the case where the direction of the bar-shaped characteristic magnetic field is not fixed to the direction of the uniform static magnetic field applied in a superimposed manner, but is tilted by a desired angle 1y. Also, for convenience, scanning of a bar-shaped characteristic magnetic field by four parallel lines will be described as an example.

Therefore, the operating principle of bar-shaped feature magnetic field scanning in the first embodiment described above is that when a uniform scanning magnetic field directed in the scanning direction is applied in a superimposed manner, the magnetic field due to the parallel stripes and the scanning magnetic field are The point of zero magnetic field moves to the point where ′ are equal in opposite directions, and as the zero magnetic field point moves, the bar-shaped characteristic magnetic field moves in parallel. Therefore, by further developing this operating principle, as shown in Figure 8, the vectors of the magnetic fields are parallel to each other in the X direction,
If a scanning magnetic field gz-2 whose magnitude is linearly changed 20,000 times is used, such scanning magnetic field g
By superimposing z'-z on the bar-shaped characteristic magnetic field, the x-direction magnetic field component due to the parallel j'4-Sei group (X-direction magnetic field 1 part of the IR field and scanning magnetic field g2・zl7) is canceled. 2
In addition to linearly varying the axial direction, it becomes possible to tilt the direction of the bar-shaped feature by a certain desired angle 1i from the two axial directions. 1. As mentioned above, the scanning magnetic field HS with a gradient in the two-axis direction IX = g7J-z (81
When superimposed on the rod-like characteristic magnetic field formed by a group of parallel lines, the characteristic 4JB and the field Q are expressed by the following equations by combining both magnetic fields.

As you can see from this equation (9), it is due to synthesis! (The position of the center of the ′♀ magnetic field exists on the straight line z (JO) in the ZX plane, and the direction of the companion !l″f sign 41i:Ifi is also tilted in the direction of this 1σ line. Therefore, the uniform If the direction of the static magnetic field -Ho, 1-, that is, the inclination angle from the Z axis, is ψ, then it becomes 1..., and in this equation (11), the value of g2 is:
Since it is possible to change the amperage of the scanning magnetic field generating coil by changing the amperage, the inclination angle, ie, the direction angle, can also be changed as desired. In this case, the magnetic field isotube in the xy plane at the coordinate position RZ in the Z ii'l11 direction is circular, as is clear from equation (9), but in the direction of the combined bar-like characteristic magnetic field. When viewed, as the direction angle ψ increases, the magnetic field contour line becomes an oval shape in the y direction. However, it is possible to correct such a change in the shape of the high purity of the magnetic field, for example, by providing a group of parallel lines for compensation and slightly weakening only the positive magnetic component in the X direction. can do. In addition, the above IE t, and the same fat (-shite, y
It is of course possible to tilt the direction of the bar-like feature magnetic field to any desired angle with respect to the axial direction, or even any direction.

Next, the first implementation i+ in which the bar-shaped feature magnetic field is translated in parallel
+h scanning method and bar shape! If the scanning method of the second embodiment is used in conjunction with the scanning method of the second embodiment in which all 1゛4 magnetic fields are tilted at an arbitrary angle, the bar-shaped characteristic magnetic field can be tilted at an inclination angle ψ in the ZX plane.
It becomes possible to scan in the direction of 1. As shown in FIG. 4, a rod-shaped characteristic magnetic field 9 that is sufficiently long compared to the size of the sample 8 is applied with an inclination angle ψ, and the rod-shaped characteristic magnetic field 9 is
When scanned in the X-axis force direction by the above-described scanning method, the sample 8 intersects with the sample 8 in an inclined state by a -angle ψ, as shown in the figure. Therefore, inside a bar-shaped feature magnetic field, the Larmor frequency, which represents the amount of rotation of the magnetic moment of the particle caused by the action of the magnetic field, is exactly the same in the length direction, and at any point in the length direction Since there is no distinction, such a mode! L\magnetic field scanning is effectively equivalent to scanning in the direction of the inclination angle ψ. Inclination in the tp characteristic magnetic field scan in a bending mode, moving distance t9 in the direction of the angle ψ. is the scan in the X-axis direction…tψ=X8008ψ” for Xs
(It has a 1, 1 coefficient of 121. Therefore, if the VcX-axis direction scanning field By extracting only the Larmor frequency component at the center of the bar-shaped characteristic magnetic field, it is possible to scan a fixed width in the direction of the bar-shaped characteristic magnetic field. It is possible to obtain an image that projects the spin density distribution of A divided tomographic image of the spin density distribution can be created by performing a d1 calculation process similar to that used when forming a cross-sectional tomographic image.

However, either the direction of the tilt angle should not be included in the projection direction during image formation, or the entire sample may be mechanically rotated only in the vicinity of the tilt angle to generate images in different projection directions. It is recognized that it is possible to form this type of computed tomographic image of the whole area of the sample without any trouble if all the operations that preserve and shape the sample are used together, and it is possible to form a computed tomographic image of the sample without any mechanical operations. It is now possible to obtain spin density distribution tomograms.

As mentioned above, as a method of forming a cross-sectional image of the spin density distribution by calculation processing applying the nuclear magnetic resonance phenomenon, a tomographic image forming method using a linear magnetic field gradient called so-called zoom chromatography is a conventional method. However, in this conventional well-known spin density distribution tomographic imaging method, it is necessary that the linear magnetic field gradient used has extremely good linearity, and furthermore, it is necessary that the linearity of the linear magnetic field gradient used be extremely good. In order to obtain a good-quality tomogram with a high signal-to-noise ratio and a detector with sufficiently wide-band characteristics that can cover the area, it is necessary to integrate the results of multiple calculation processes for the fourth time. Necessary and practical implementation
j′ It seems to be extremely difficult. On the other hand, in the spin density distribution tomographic image formation according to the present invention in the above-described aspect, it is sufficient to detect the Larmor frequency of a single frequency component, and therefore countermeasures against external noise are extremely simple and easy. Also, it is easy to form a clear tomographic image with a good V signal-to-noise characteristic using a narrowband amplifier. However, if you use an amplifier with narrowband characteristics, the response 'F4? Since sex is slow, it is inevitable that
Although it is necessary to scan the characteristic magnetic field slowly, I
X Unlike the conventional method described above, in order to faithfully represent the entire Larmor frequency spectrum, there is no need to repeat complex calculation processes over a wide frequency range, which is considered unnecessary compared to the method of the present invention. Therefore, if we compare the total hair cutting time required to create one tomographic image, the method of the present invention has the possibility of being much shorter. Furthermore, in the conventional method described above, a separate means must be used to determine the position at which the sample is to be sliced to form a tomographic image, whereas in the method of the present invention, a rod-shaped! Another advantage is that once the diameter of the F-force magnetic field is determined, the position of slicing the sample through scanning is automatically determined.

As is clear from the above description, according to the present invention, in applying the nuclear magnetic resonance phenomenon to detect and image the entire spin density distribution of a nuclear magnetic material that represents information inside a sample,
Scanning of the bar-shaped feature magnetic field used to detect the spin density distribution can be easily performed using a device with a simple configuration.
The i-layer image can be realized by simple q-processing of the detected spin density distribution within the sample.

[Brief explanation of the drawing]

Fig. 1 is a miniature diagram showing an example of the mode of bar-shaped feature magnetic field generation by a group of parallel wires, Fig. 2 is a diagram showing an example of the mode of bar-shaped feature magnetic field scanning according to the present invention, and Fig. 3 is a diagram showing an example of the bar-shaped feature magnetic field generation mode according to the present invention. A diagram showing another example of the scanning mode; FIG. ], 2, 8, 4, 7, 7'... Parallel lines for forming a characteristic magnetic field, 5, 5', 6. (3'... Parallel lines for scanning, 8... Sample, C)... Bar-shaped characteristic magnetic field. Bamboo permit applicant Uh158 University president procedural amendment October 1982 60 -, Minor case display 1988 4,? Patent Application No. 159438 2, Name of the invention Characteristic magnetic field scanning method in nuclear magnetic resonance imaging 3, Person making the amendment Relationship with the case Special IT Applicant: President of Utsunomiya University Akira Ibi, 1 person outside the department 5゜7, Amendment Contents (as attached) The scope of claims is amended as follows. "2. Claim 1. In order to measure internal information of a measured object placed in a static magnetic field (Ho) by a nuclear magnetic resonance phenomenon, the static magnetic field (Ho)
) and the magnetic field generated by the coil group or magnet group to generate a characteristic magnetic field (ΔH8), and a predetermined magnetic field component of the magnetic field generated by the coil group or magnet group that controls the change in the magnetic field intensity of the characteristic magnetic field (ΔHs). By superimposing and changing the scanning magnetic field in the direction, the characteristic magnetic field (Δ
1. A characteristic magnetic field scanning method in nuclear magnetic resonance imaging, characterized in that the center of Hs) is spatially moved. 2. Having only a magnetic field component approximately parallel to a predetermined plane generated by a group of mutually parallel wires or a group of differentially combined coils or magnets, and that magnetic field component is generated at a point within the predetermined plane. Generate the characteristic magnetic field (ΔHs) by creating a zero magnetic field point that becomes zero and combining the magnetic field that increases with distance from the zero magnetic field point and the static magnetic field (Ho) in the direction perpendicular to the predetermined plane. By doing so, a bar-shaped characteristic magnetic field whose magnetic field height forms a closed curve around the normal line passing through the zero Ij field in the predetermined plane is formed. When moving, the characteristic magnetic field component generated by the scanning magnetic field generating means is superimposed on the scanning magnetic field which is not equal except for one point within the predetermined plane, thereby generating the characteristic magnetic field component within the predetermined plane. The zero magnetic field point is moved within the predetermined plane by canceling the zero magnetic field point, and the amount of movement of the zero magnetic field point is changed by changing the amperage of the scanning magnetic field generating means. A characteristic magnetic field scanning method in nuclear magnetic resonance imaging according to scope 1. Akira: A change in the magnetic field component of the characteristic magnetic field (ΔH8) in a direction orthogonal to the direction of the static magnetic field (Ho) within the predetermined plane becomes a substantially linear function, and the direction of scanning is directed within the predetermined plane. A uniform magnetic field is used as the scanning magnetic field so that the movement of the zero magnetic field point becomes a linear function of the strength of the scanning magnetic field. +, Features in the nuclear magnetic resonance imaging method described in Q 1e field scanning method. Soil: The direction of the scanning magnetic field is always the same as the static magnetic field (Ho).
By linearly changing the magnitude of the scanning magnetic field in the direction of the static magnetic field (If), the direction of the bar-shaped characteristic magnetic field is changed to the direction of the magnetic field. Feature II', characterized in that the magnetic field (Ho) is tilted by an arbitrary angle from the direction of the static magnetic field (Ho). 2. The following is added on page 4, line 13 of the specification. "Here, an example of a schematic configuration of a nuclear magnetic resonance imaging apparatus to which the present invention is applied is shown in FIG. constitutes a basic pulse NMR device together with the transmitter coil b0, receiver coil b2, and magnet b6 for generating a static magnetic field in the unit 2. Each i1i+l+ of the transmitter coil b□ and receiver coil b generates a static magnetic field. The generating magnet b is arranged in a direction orthogonal to the uniform static magnetic field H8 generated by the generating magnet b, and the object to be measured is placed inside it. When an RF magnetic field with a frequency equal to the Larmor frequency is applied to the object to be measured by the transmitter coil b,
A nuclear magnetic resonance phenomenon occurs in the body to be measured, and the receiver coil b
is induced by a signal of that frequency. Therefore, since the Larmor frequency is uniquely determined by the magnetic field strength,
A limited measurement area within a large object
ringTarget: M T ) (7) Mino N
In order to obtain MR information, the change in magnetic field strength within region MT is extremely small, and a difference in nuclear magnetic resonance frequency occurs between region MT and the outside by applying a characteristic magnetic field outside of region MT. It is possible to selectively measure information within a single area, separate from information outside of it. This main field a is converted into γIt by the scanning coil b8 in the unit 2 without changing its shape.
As a result, NMR parameters such as spin density distribution and nuclear magnetic relaxation time within the body to be measured can be mapped and displayed as images. Here, to further explain in detail the configuration and operation of each unit, unit 1 constitutes the circuit system of a basic pulse NMR device, and unit 2 consists of a magnet for generating a static magnetic field, b5, and its static magnetic field. It consists of a magnetic field generating/scanning coil b8°b and a transmitter/receiver coil b0°b2. In addition, the characteristic magnetic field generation/scanning coil b3. Depending on the configuration, magnet b may be placed outside the static magnetic field generating magnet b5. Unit 8 is a drive source for unit 2, and unit 4 is a computer that controls the entire device, controlling the irradiation pulse magnetic field, sampling measurement data, frequency analysis, controlling image display, etc., and its peripheral devices. It consists of d2. With the configuration described above, the frequency equal to the Larmor frequency corresponding to the central magnetic field strength of the characteristic magnetic field given by unit 2 (7) The RF multiplied signal from the RF generator a□ enters the waveform shaping and gate circuit a8. , Calculation 4L (
The RF pulses are gated by the output pulses of the program pulse generator a2 controlled by the program pulse generator a2 and are amplified by the RF power amplifier a and then supplied to the transmitter coil b. In this way, an RF magnetic field is applied to the object to be measured by the transmitter coil b, and the RF magnetic field having a predetermined frequency spectrum applied to the object to be measured spreads a predetermined area surrounding the center of the characteristic magnetic field in the object to be measured. The nuclear magnetization of is selectively excited. The excited nucleus (+θ) produces a magnetization component in a direction perpendicular to the static magnetic field, and the magnetization component becomes maximum when the excitation RF pulse satisfies the conditions of a so-called 90) pulse. Then, when the excitation RF pulse ends, the nuclear magnetization component in the direction orthogonal to the static magnetic field performs free precession interlocking at the Larmor frequency corresponding to the magnetic field strength at each position 1σ of the characteristic magnetic field, and transmits " Induces a small RF voltage.The RF pr
t++: , iiQ if'2 and each main amplifier a
After amplification by Fi and R6, the phase-sensitive detector a7 detects the oscillation output of the RF generator a1 as a reference signal, resulting in a so-called free decay signal (FreeIn).
culmination Decay: “FID”
is obtained. This FID signal is converted into a digital signal by an A/D converter a8, and then frequency-analyzed by a computer d4 using the so-called FFT method, and a frequency component corresponding to the central magnetic field strength of the characteristic magnetic field is extracted. At the same time as this frequency component extraction, a characteristic magnetic field scanning signal is sent from the computer d0, and a scanning current is supplied to the characteristic magnetic field scanning coil b3 via the D/A converter 01, so that the characteristic magnetic field almost changes its shape. Due to such scanning, an offset occurs in the center magnetic field strength in certain characteristic magnetic fields, but this offset is compensated for by a compensation coil placed in parallel with the scanning coil b8, and the center of the characteristic magnetic field is The Larmor frequency at is always kept constant.The drive current supplied to this auxiliary 1i1 coil is also given by the computer d□.While performing the characteristic magnetic field scanning described above, By mapping the intensity of the Larmor frequency magnetization component, it is possible to directly obtain a spin density image, and if the pulse train is set appropriately, direct measurement of T□ and T2 is also possible. In addition, in order to extract the Larmor frequency magnetization component corresponding to the central magnetic field 4jjJ degrees of the characteristic magnetic field, R as shown in i43 above is required.
It is clear that in addition to digital arithmetic processing using a computer, direct analog circuit processing using narrowband selective amplifiers, lock-in amplifiers, etc. can also be used. The present invention provides a specific method for scanning a characteristic magnetic field using a characteristic magnetic field scanning coil in a nuclear magnetic resonance imaging apparatus configured as described above. 4. Correct "1 focal point 16 fields" in lines 9, 12, and 18 of the same page to "1 characteristic magnetic field." 4. Lines 11, 12, 19, and 2 of page 6 of the same page.
1-focal magnetic field” in line 0 is revised to “characteristic magnetic field” respectively IF
shi, change the ``above direction'' in line 15 of the same page to [the above-mentioned equilibrium (+'
dj in the direction of the li field H8. ), No. 7 corrects the "focal magnetic field" in lines 7, 9, 12, and 19 to "characteristic magnetic field", respectively, and adds the following to line 8 of the same hundred. do. 1-Figure 2 (→, shows an example of the mode of generating a magnetic field with a bar-like characteristic according to (b).) 3. Revised ``Figure 1'' to ``Figure 2'' on page 8, line 9 of the same page.
:, ShiN Same 11, lines 18 to 19, "X magnetic field component and y magnetic field component" are corrected to "X-axis direction magnetic field component and X-axis direction magnetic field component". "Illustrated" is corrected to "Second illustration". "Each magnetic field component" in the first line of page 9 of Iruma is "(1
8 field components", deleted ", especially, equation (4)" in the second line of the same page, and
The "1st illustration" in line 4 is corrected to "2nd illustration" and the "Fig. 2" in lines 14 to 15 of the same page is corrected to "Fig. 3." 8. "Figure 3" on page 12, line 5 is corrected to "Figure 4." 9 Corrected “Figure 4” on page 14, line 14 of the same page to “Figure 5” and added “Magnetic field action...” from line 20 of the same page to line 2 of page 15.
"Larmor frequency" is corrected to "There is no change in magnetic field strength, Larmor frequency". 10 The same 15th v. line 20 to 16 @ 1st line “by X-rays...J゛1 Similar calculation process” to 1G by X-rays
Corrected to ``Computation processing similar to T (compute6a Tomography)''. 11. Delete “extremely” from line 4 on page 17,
Same @ Lines 5 and 6, "There is a need, and it seems that..." is corrected to "There is a need."
Delete the word "clear" in the second line, and replace "it is easy." in lines 12 to 18 on the same page. ] to be corrected. ]2. On page 18, line 16, after “tomographic image,” there is a 1 “
Bar-like features obtained by scanning the magnetic field are added. The 17th line of the same page was corrected as follows, and the following was added to the 19th line of the page: ``In the calculation process of the results of the spin density distribution within'', and ``Figure 1 shows the present invention. Outline 4 of the nuclear magnetic resonance imaging device to be applied (Block diagram showing an example of 4), ``Figure 1'' on the same page @ line 20 is corrected to ``Figure 2''. 18 Same page 19 ``Figure 2'' in the second line of the page was corrected to ``Figure 8'', ``Figure 1 Figure 8'' in the 4th line of the page was corrected to ``Figure 4 J'', and ``Figure 4'' in the 6th line of the page "Figure" has been corrected to "Figure 5" and the same has been added after the 7th line as follows: [a□...RF oscillation a, C2...Program pulse generator, C8... Wave Cedar shaping and gate circuit, a,・
...RF power multiplier, a... preamplifier, C
6... Main amplifier 11'bi device, C7... Phase sensitive detector, C8... A/D conversion n, b□... Transmitter coil, b2... Receiver coil, b8... Characteristic magnetic field scanning coil, b4...Characteristic magnetic field generating coil, b5.
・Magnet for generating a uniform magnetic field, 0.0...D/A converter, C2, c4...Direct 8 current power increaser 111M, C6...Highly stable DC, <power amplifier...DO...Control computer , C2...Peripheral equipment,'' 14, Figures 1, 2, 8, and 4 in the drawings have been replaced with Figures 2, 8, 4, and 5 as shown in the attached corrected drawings. Make corrections to each figure and submit a new copy of Figure 1. 12'. 731 Suppression 271- (Kani 1 Sword) Izai Ibe”・Da 1 Sword

Claims (1)

[Claims] L: In order to measure the internal information of the object to be measured placed in the static magnetic field (H8) by the nuclear magnetic resonance phenomenon, the static magnetic field (Ho)
and the magnetic field from the coil group or magnet group to generate a characteristic direct field (ΔI (6), and the characteristic magnetic field (ΔH8) 411 (field strength 1) Nuclear magnetic resonance imaging characterized in that the center of the characteristic magnetic field (ΔHS) is spatially moved by changing the direction of the 75i constant magnetic field component of the magnetic field caused by the group. Features of the magnetic field scanning method A zero magnetic field point that becomes zero at one point in the above plane is formed, and a magnetic field that increases with distance from the 7'J magnetic field point, the static magnetic field (Ho) in the direction perpendicular to the r9f constant plane, and t. By synthesizing and generating the characteristic magnetic field (ΔH8), a bar-shaped characteristic magnetic field whose magnetic field contours form a closed curve around a normal line passing through the zero magnetic field point in the predetermined plane is formed. A characteristic magnetic field scanning method in nuclear magnetic resonance imaging according to claim vj 1. 8. Spatially shifting the center of the bar-shaped special gi magnetic field Iυ
In doing so, the characteristic magnetic field components generated by the scanning magnetic field generating means 1 are superimposed on the scanning magnetic field which is unequal except for one point within the predetermined plane, thereby generating a magnetic field within the seven fixed planes. 1. Moving the zero magnetic field point within the predetermined plane by canceling the characteristic magnetic field component.
. . . and, by changing the ampere frequency of the scanning magnetic field generating means, the moving k of the zero magnetic field point is changed.
Characteristic magnetic field scanning method in nuclear magnetic resonance imaging described in Section 1. 4. Above! The above-mentioned static direct field () of the time magnetic flux (ΔH8)
A change in the magnetic field component in a direction perpendicular to the direction of Io) within a predetermined plane becomes a linear function, and a uniform magnetic field directed in the scanning direction within the predetermined plane is used as the scanning magnetic field. The nucleus according to the first, second or eighth item of the patent H blue water range, characterized in that the movement of the zero field point becomes a linear function of the strong variation of the scanning magnetic field. Characteristic magnetic field scanning method in magnetic resonance 1゛H report. The direction of the eclipse is always the same as that of the static magnetic field (l).
(.), and in the direction of the static magnetic field (Ho), the magnitude of the magnetic lift for scanning is siJ. The direction of the characteristic Qi field is expressed as the static 4rR field (
9. A characteristic magnetic field scanning method in nuclear magnetic resonance imaging as claimed in claim 2 or 8, characterized in that the magnetic field is tilted by an arbitrary angle from the direction of (Ho).