JP3164112B2 - Biological measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical imaging device which non-invasively measures medical information in a living body and displays the image as an image. In particular, the present invention relates to a quantitative distribution of biological functions such as metabolic circulation as an image. An apparatus suitable for providing.

[0002]

2. Description of the Related Art Diagnostic devices used for medical diagnosis are classified into a morphological diagnostic device that measures and displays the external shape of a living body and the shape of an organ, and a functional diagnostic device that measures functions such as circulating metabolism in a living body. be able to.

[0003] Among them, MRI is used as a morphological diagnostic device.
(Magnetic Resonance Imaging) The development of high-precision diagnostic imaging equipment such as X-ray CT equipment has made it possible to non-invasively and accurately diagnose "morphological abnormalities" in living bodies. I have. However, in general, morphological abnormalities of living organs and the like are caused by abnormalities in biological functions such as metabolic circulation.At the time of detection of morphological abnormalities, functional conditions such as metabolic circulation have already progressed, and treatment is Often difficult or prolonged treatment period.

[0004] Therefore, it is a major task in modern clinical medicine to detect a functional change of a living body prior to a morphological abnormality at an early stage and to perform an accurate treatment. Also, there is a strong demand for the development of a 'biofunction diagnostic device capable of early diagnosis' as a tool for that purpose.

[0005] By the way, as a device capable of performing a function diagnosis, a sample test device for blood or urine is well known. In the sample test, the amount and function of metabolites in living tissue are directly measured chemically and physically, so that a quantitative function diagnosis can be accurately performed. However, although it is possible to measure a systemic abnormal state in a specimen test of blood, urine, etc., it is difficult to accurately determine an abnormal site as in morphological diagnosis.

[0006] For this reason, a doctor first determines a systemic abnormality by a functional diagnosis such as a sample test, and further determines an abnormal site by a morphological diagnostic device such as an X-ray diagnostic device. It is the present condition that a diagnosis of a disease is made based on judgment. However, it is very difficult to accurately judge an abnormal site and its condition by combining image information obtained by morphological diagnosis and functional diagnostic information such as a sample test. However, an increase in the physical and economic burden on the patient has become a problem.

[0007] As a medical diagnostic apparatus capable of solving the above-described problems, an apparatus capable of measuring functions and further imaging and displaying the spatial distribution thereof, that is, a biological function imaging apparatus has been devised and developed.

For example, an attempt has been made to add a position detection capability to a conventional biological function measuring device and obtain a spatial distribution of functional quantities with a single diagnostic device. An example of such an example is the conversion of a nuclear magnetic resonance spectrum analyzer into an image apparatus. By measuring the chemical shift of the nuclear magnetic resonance frequency of the P ³¹ using fine measurement of nuclear magnetic resonance spectrum, the metabolic processes of the living tissue can be measured are previously known application image apparatus it to biological Attempts have been made to commercialize MRS imaging apparatuses.

The signal measured in the nuclear magnetic resonance spectrum measurement is a displacement of the absorption amount of a very weak electromagnetic wave. For this reason, using such signals to further image the metabolic rate as a spatial distribution requires a very long measurement time, and a practical device has not yet been completed.

Since a device capable of measuring a change in biological function as in this example needs to capture qualitative information of a living body, it is necessary to physically measure a very weak signal change.
Furthermore, it is more difficult to express a physical quantity indicating a function of a living body from such a weak measurement signal as a spatial distribution, that is, it is more difficult to make an image, and an image finally obtained by such an apparatus is a conventional X-ray CT apparatus or It is expected that the spatial characteristics are very inferior to those of the MRI apparatus.

Researches on such a biological function imaging apparatus which are currently being studied include a nuclear magnetic resonance apparatus, a biomagnetic distribution measuring apparatus, a biological light measuring apparatus, and a PE.
T (Positron Emission Tomography).

These devices have not yet reached clinically practicable levels except for PET. In PET, a sufficient spatial resolution has not yet been obtained, and at present, an image from a morphological diagnostic apparatus such as an X-ray CT apparatus is used to compensate for this. This is an example of the combination of the function diagnosis and the morphological diagnosis described above.

In addition to the use of such a morphological diagnostic device,
Many attempts have been made to improve the spatial characteristics of these biological function imaging devices, but sufficient performance has not been obtained.

For example, a living body optical imaging apparatus irradiates a living body with light, measures scattered transmitted light from the living body, and performs various functions in the living body to form an image.
32 proposed. It has been pointed out that this apparatus can be an ideal biological function image diagnostic apparatus because it has very little damage to the living body. Also in this biological optical imaging device, low spatial performance is a serious problem in practical use.

In light measurement in a living body, it is said that it is difficult to image a function distribution in a living body, particularly in a deep part, because scattered light generated inside a subject is added to measurement data and disturbs position information.

As a method of improving the spatial resolution of the living body optical imaging apparatus, the present inventors propose to remove the influence of scattered light by a combination of a time gate method for limiting a light path using a time gate and a multi-wavelength method. are doing.

[0017]

Research on imaging devices for biological functions has not yet led to the development of practical devices. Even the most practical device PET has insufficient spatial characteristics, and actual diagnosis requires image information obtained by a morphological diagnostic device such as an X-ray CT device. It was mentioned earlier that such an example can be found in other function measuring devices.

As described above, the conventional combination of the function measurement and the morphological measurement is performed by displaying two kinds of images measured at different points in time by different devices in parallel, thereby obtaining spatial information in the function measurement. It aims to make up for the shortage. However, in the above-described method, since the two measurements are performed at different devices and at different times, the mutual geometrical positional relationship cannot be accurately grasped. Further, when there is a spatial distortion due to various physical effects in the function measurement image, it is impossible to correct this. As described above, it is difficult for the conventional method to perform an accurate medical diagnosis by grasping the exact positional relationship between the images of the function and the form.

Apart from this, attempts have been made to improve the spatial characteristics of the function measuring device itself, but satisfactory results have not been obtained due to difficulty in measurement. Further, even if these attempts are effectively performed, it is expected that the spatial characteristics of the obtained image will not reach the point where other morphological diagnosis is not required.

The present invention compensates for the lack of positional information in such biological function measurement, and at the same time, improves the spatial resolution of the function measurement image itself and reduces image distortion, thereby enabling more accurate diagnosis of functional abnormality. The purpose is to provide a simple method.

[0021]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned conventional disadvantages. For this reason, the living body measuring apparatus of the present invention measures and images the functions such as metabolic circulation of a living body. The part having the function and the part having the function of measuring the anatomical form of the living body are configured in one device, and the measurement of both can be performed simultaneously or sequentially without moving the measurement target.

The morphological information of the object measured by the morphological measuring unit is used in the process of converting the functional information obtained by the functional measuring unit into an image, and furthermore, the spatial distribution of the functions is displayed on the display unit on the same screen as the image. Is displayed. The part for measuring the form uses the principle of a form measuring apparatus such as an X-ray CT apparatus or an MRI apparatus.

The part for measuring the function distribution is constituted by, for example, a living body optical imaging apparatus for measuring the function of a living body by detecting light and scattered transmitted light. The biological optical imaging device includes an optical input unit configured by a number of optical fibers,
It comprises a light detection unit composed of a plurality of optical fibers, and an output unit of the detection unit inputs to a high-speed optical time spectrum measurement unit. The function measuring unit is not limited to the optical imaging device as long as it is a device capable of measuring other functions and measuring a spatial distribution.

In the display section of the measurement image, only the boundary portion of the tissue is displayed in a single color for the image indicating the morphology, and the image indicating the function is displayed in a different color from the morphological image so as to overlap the image. The image showing the function distribution may display the difference from the standard value obtained from a medical standard in shades or hues.

Since the morphological diagnosis unit and the function diagnosis unit are integrated, the diagnosis of both can be measured with little spatial displacement in a short time, and the spatial positional relationship between the measurement information of both can be accurately detected. Therefore, in the process of imaging the spatial distribution of the function measurement results, the morphological information can be effectively used. This makes it possible to increase the speed and accuracy of the function distribution imaging process.

Furthermore, since both images are displayed on the same screen, the anatomical positional relationship between the function distribution images can be accurately determined, and accurate diagnosis of a disease can be made.

Further, since the processing device, the image display unit, the bed, and the like used by the two function units can be shared, the space utilization can be made more efficient and the price can be reduced. Further, since both diagnoses can be performed without moving the patient, the examination time can be shortened and the burden on the patient can be reduced.

Further, by superimposing and displaying the boundary image of the form on the function distribution on the display unit, the anatomical positional relationship of the function image can be clarified and the diagnosis efficiency can be improved without impairing the information of the function image. By displaying the function distribution image corresponding to the deviation from the medical standard value, the determination of the abnormal part is further facilitated.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an entire configuration of an embodiment of the present invention, which is composed of a form measuring section for diagnosing a form and a function measuring section capable of performing a functional diagnosis. Form,
An image reproducing unit 80 and an image display control unit 100 for reconstructing and displaying an image from the measurement results of both functions are provided in common for both measurement units. The morphological measurement unit uses the principle of an X-ray CT apparatus, and includes an X-ray source 3 and an X-ray detector 1 that rotate around a copy target. The X-ray projection data detected by the X-ray detector 1 is taken into the data collection unit 70 of the X-ray measurement unit. The function measurement unit uses the principle of a living body optical imaging device that irradiates light to a living body, measures the scattered transmitted light, and measures the distribution of metabolites, and includes a measurement cap 20, a light source unit 30, and a light It comprises a detection unit 40, a timing control unit 50 for controlling them, and a data collection unit 90 for recording the measurement results. The data of each data collection unit for X-ray measurement and optical measurement is processed by the image reproduction unit 80 and displayed on the display unit 105 via the image display control unit 100. These devices are all controlled by one computer 60.

In the above-described apparatus configuration, the morphological measurement unit is an X-ray C
Not only the T apparatus but also a morphological diagnosis apparatus such as an MRI apparatus, which can accurately measure and image a tomographic image inside a living body, typically, can be configured. The function measuring unit is constituted by a device having a function of quantifying a function such as circulating metabolism of a living body and measuring the function as a spatial distribution. The biological function measuring means applicable to the present invention includes the above-described biological optical imaging device (optical C
T), a nuclear magnetic resonance spectrum distribution measuring device (M
RS imaging device). A biomagnetic field distribution measuring device (brain magnetic distribution measuring device) or the like can be applied. The device is not limited to the above device as long as it is a device capable of measuring functions such as circulation and metabolism of a living body and capable of measuring a spatial distribution.

FIG. 2 shows the appearance of the apparatus of the embodiment shown in FIG. 1 in which the principle of a biological optical imaging device is used for the function measuring section and the principle of the X-ray CT apparatus is used for the morphological measuring section. 2 is an example of an apparatus for a unit. The principle of the living body optical imaging apparatus is described in detail in, for example, Japanese Patent Application Laid-Open No. 57-115232. Apparatus main body 11 on which each part of FIG. 1 is mounted
The head of the subject lying on the head 120 is inserted into the gantry opening of No. 0. This structure is a conventional X-ray CT
Same as the device. Further, the present embodiment is characterized in that it has a function of holding the measurement cap 20 of the function measurement unit in the gantry opening.

FIG. 3 shows a measurement area in the present apparatus. The measurement area 4 of the X-ray CT apparatus section is configured to include the measurement area 5 of the biological optical imaging measurement section.
Reference numeral 3 denotes an X-ray generation unit, and reference numeral 20 denotes a measurement cap in the biological optical imaging device.

Next, FIG. 4 shows a detailed configuration of the living body optical imaging measurement unit.

As shown in FIG. 4B, the optical fiber 12 for guiding light incident from the light source unit 30 to irradiate the object cap 20 and the detected light to the light detecting unit 30 are provided on the subject cap 20. An optical fiber 14 is provided. A plurality of these two types of optical fibers are provided.
These ends are arranged along the circumference of one section of the inner surface of the cap 20. When the cap 20 is mounted on the head of the subject, the imaging cross section of the X-ray CT apparatus and the cross section where the end of the optical fiber is arranged are adjusted by adjusting the position of the bed 120 in FIG. Thus, the measurement visual field of the morphological measurement unit and the measurement visual field of the function measurement unit are on the same cross section, and the former includes the latter.

As shown in FIG. 4A, the light source 30
It can irradiate a short pulse of less than 00 psec repeatedly. 2
Laser devices 8-1 and 8-2 having different wavelengths, and a light source controller 6 and a wavelength switcher 7 for selecting one of the lasers and switching the wavelength of irradiation light at an arbitrary time interval. This configuration example is a configuration of two wavelengths, but the number of wavelengths of the light source is not limited to this. For example, in measuring the oxygen saturation of hemoglobin in blood, the isosbestic points (805 nm) of oxygenated hemoglobin and deoxygenated hemoglobin ) And another one point wavelength (for example, 600 nm) and each one point near each wavelength needs to be measured at a total of four points. In such a case, there are four light sources.

The laser light beam emitted from the laser 8-1 or 8-2 and selected by the wavelength switching unit 7 enters the optical scanning unit. The light scanning unit is constituted by a rotating mirror 9 and scans the traveling direction of the laser light.

The light beam whose traveling direction is deflected by the mirror 9 is applied to the other end 11 of the irradiation optical fiber 12 shown in FIG.
Are incident on the light distribution unit 10 in which the light beams are arranged, and are sequentially changed according to the scanning angle of the rotating mirror 9, for example, the input unit fiber numbers 1, 2, and 2.
Enter in the order of 3 ,,. As a result, light is detected in time series from the output section of the fiber 12 of the measuring cap 20, and light is sequentially applied to the living body in accordance with the arrangement of the optical fibers. By controlling the timing of the light scanning and the light source pulse emission, it becomes possible to input a set number of light pulses to a given fiber at a set timing.

Here, by freely controlling the mirror rotation position of the light scanning unit by the pulse control motor, light irradiation can be performed in a desired free order (instead of 1.2) regardless of the arrangement of the fibers. I can do it. The order of light incidence and the number of set pulses are determined by the control unit 6 according to the size and shape of the subject so as to minimize obstacles to the living body and enable optimal image measurement.
Can be set, so that a diagnosis can always be made in an optimal measurement state.

Further, since the light scanning wavelength switching unit 7 is added to the light scanning unit, it is possible to irradiate light of a plurality of wavelengths at a high speed in accordance with a set schedule.

The light incident on the subject passes through the subject, is absorbed in accordance with the characteristics of each biological metabolite, is scattered by living tissue, and is emitted from the surface of the subject. This is guided to the light detection unit 40 via the optical fiber 13.

FIG. 5 is a diagram showing the details of the light detecting section 40. As shown in FIG. The light collecting unit 13 in the measuring cap 20 is composed of an optical fiber 14 and a plurality of lenses, and is disposed so that the focal point of the optical system is always set near the surface of the subject.

The transmitted and scattered light from the subject incident on the light collecting unit 13 is guided to the light detecting unit 40 through the optical fiber 14.

The light detecting section 40 of this embodiment uses a device capable of measuring and recording a change in light intensity at high speed, hereinafter referred to as an optical time spectrum measuring device. The optical time spectrum measuring device has a high-speed time response and can measure and store a time spectrum, so that a time gate can be set without using an optical shutter.

The measurement light guided by the plurality of optical fibers 14 from the subject cap 20 is incident on the light receiving surface 16 of the streak camera at appropriate intervals. The light is input surface 1
At 6, the light is converted into electrons and travels toward the fluorescent screen 18. The AC electric field generator 17 changes the scanning direction of the electrons at a high speed. As a result, a distribution image corresponding to the time change of the input light is displayed on the fluorescent screen 18. By reading this distribution image with a TV camera or the like, the time change of the light intensity can be measured at high speed. By the way, the high-speed pulse light source 8-1 or 8
Light having a delay time corresponding to the traveling process of light is emitted from the surface of the object irradiated with the light through the optical fiber 12 according to -2 with a time distribution as shown in FIG. The light further forms distribution data as shown in FIG. 5B on the fluorescent screen 18 of the optical time spectrum measuring device via the optical fiber 14. In the distribution (b), the vertical direction corresponds to time, and the Y horizontal direction corresponds to a position near the surface of the subject where the light collecting unit 13 of each fiber is arranged. In such a time distribution image, a portion that has passed a certain time or more after the light pulse irradiation is light that has repeatedly scattered and bent in the subject and has come around, so that such a scattered ray is removed. 6 over time gate as hatched portion R ₁ of (a), the integral value of the light amount of the part and the detection data. In the present embodiment, a function of a time gate is realized by processing a part of a specific range in an optical time spectrum image read and recorded by a TV camera or the like by a computer, and a desired transmitted light amount is obtained.

The measurement as described above is performed using the irradiation position of the light pulse,
In other words, by sequentially selecting the irradiation fibers, the light transmission characteristics due to light incidence from multiple directions of the subject are measured,
This makes it possible to obtain all data necessary for imaging the three-dimensional optical characteristic distribution of the subject.

The above-mentioned time-series selection of the fiber is based on the conventional X
It has the same effect as X-ray source scanning in a line CT apparatus. If the measurement data obtained by the above configuration is subjected to arithmetic processing based on CT image reproduction theory, the optical characteristic distribution of the object can be imaged. For the principle and method of such image reproduction, see “Image Reconstruction from
Projection ”GTHerman, 1979.

Incidentally, instead of the optical time spectrum measuring apparatus shown in FIG. 5, a time gate may be realized by employing a high-speed optical shutter as described in JP-A-63-20665.

(Procedure for Functional Image Measurement) Next, a procedure for measuring a biological function image of a biological measuring apparatus using the apparatus of the present invention will be described with reference to an example of an apparatus using the principle of the above-mentioned biological optical imaging apparatus and X-ray CT apparatus (FIG. This will be described in 1).

The subject of the present apparatus is a human head, and the subject is inserted into the measuring section of the form measuring apparatus while lying on a bed having a head holding section made of a substance having a small X absorption coefficient. .

After the above setting is completed, the measurement cap 20 which is the inspection unit of the living body optical imaging apparatus is put on the head of the subject.

The measuring cap 20 of the living body optical imaging apparatus is made of a substance having a small X-ray absorption coefficient.
Most of the irradiating X-rays from the morphological measurement unit are transmitted therethrough.
Therefore, the measurement cap is made of plastic or aluminum.

Next, X-rays are emitted with the measurement cap 20 set, and a tomographic image including the subject and the measurement cap is measured. As a result, an image as shown in FIG. 7 is obtained in the morphological measurement unit. The display area 20 includes the subject and the measurement cap of the living body optical imaging device, and the shape 21 of the subject and the shape 22 of the measurement cap are displayed.

A substance having a relatively high X-ray absorptivity is arranged at a specific position in the measurement cap. As a result, the position 23 of the absorber is specifically displayed as a high absorption area on the X-ray transmission image, so that the positional relationship between the function measurement unit, the subject, and the form measurement unit can be easily obtained. The display absorber is located at least three places on the measuring cap. This makes it possible to accurately determine the positional relationship between the X-ray image and the biological light measurement unit on the measurement screen.

As a result of the above measurement, the image reproduction processing based on the principle of CT determines the shape of the subject and the distribution of the organs within the subject, and the spatial arrangement relationship between the subject and the function measuring unit.

Here, it is desirable that both the morphological measurement and the functional measurement be performed simultaneously in order to prevent a change in the measurement position. However, the measurement may be performed in chronological order without performing the simultaneous measurement within a time that does not cause a large change in the position of the subject.

When both the measurement of the form and the function are performed in time series, the possibility of deterioration of the spatial characteristics due to the displacement of the subject position increases. However, compared to the simultaneous measurement, there is no crosstalk due to mutual physical interference. In addition, there is an advantage that the load on the measurement processing device is dispersed over time.

In the case of performing the two measurements in a time series, the order of the measurement may be either. However, since the image processing of the function measurement data requires the information of the morphological measurement image, Performing the function measurement in the order simplifies the data processing and reduces the amount of memory of the processing device.

In general, functional measurements are often repeated in a time series to measure temporal changes such as metabolism.
In such a case, the morphological measurement may be performed once at the beginning and at the end of the measurement as shown in FIG. However, when the time interval of the measurement is long, it is preferable to alternately perform the function measurement and the form measurement as shown in FIG.

Next, the operation of each part in the function image measurement will be described. It is assumed that the measurement is performed in the order of form and function.

Optical fiber 12 in measuring cap
Are sequentially irradiated with light pulses. 1.2.3. . Irradiation with the numbers shown in At this time, optical signals having a time spectrum as shown in FIG. 5A are sequentially input to each photodetector. These measurement values are stored in the storage unit until a series of measurement is completed.

Incidentally, these data contain a large amount of scattered light in the living body and cannot be used for imaging as it is. Therefore, as shown in JP-A-63-20665, scattered light is removed by a time gate. In this embodiment, the same effect can be obtained by selecting and adding data at the front part of the time spectrum with less scattered light from the time spectrum data. In this case, as the time gate width (data selection width) is smaller, the mixing of scattered light can be reduced and the spatial resolution can be improved, but conversely, the signal amount decreases. Therefore, the optimum value of the width of the time gate varies depending on the size of the subject and the light transmittance. Assuming a normal human head, the optimum width is about 100 psec.

As described above, the spectrum data is added in the time direction with the set time width. As a result, assuming that the number of light irradiation units is Ns and the number of light detection units is Nd, a series of data obtained by the above measurement is Ns × Nd numerical data.

(Image Reproduction Process) Next, a set of function measurement data obtained by the above measurement (Ns × Nd numerical data)
Then, image reproduction of the function distribution is performed using the morphological measurement image measured in advance. Hereinafter, the flow of the image reproducing process will be specifically described.

As shown in FIG. 7, an X-ray absorption image of the subject and the function measurement device is displayed on the measurement image of the X-ray CT device. In the image, a display 23 for position detection embedded in the measurement cap can be detected as a high absorption area. Good X
The measurement area is divided into N × M pixels on the line image. The exact positions of the light input unit and the light detection unit of the function measurement device are all determined from the positional relationship between the pixels and the position detection absorber. This can be easily achieved by accurately measuring and storing the structure of the optical imaging apparatus in advance.

Next, the bones, the white matter in the brain, and the gray matter are classified from the X-ray CT image. The tissue discrimination from such an X-ray CT image uses a method used for three-dimensional display of a living organ in an X-ray CT apparatus. For example, the simplest method of tissue discrimination is a method of judging from the level of the absorption value.
00 or more bone, white matter 1200-1100, gray matter 1
It is displayed as 100 or less.

Next, the function measurement area is divided into rectangular pixels according to the pixel division of the X-ray measurement image. As shown in FIG. 9A, the scattering coefficient si and the absorption coefficient mi are given as optical variables to each pixel. Here, i indicates a pixel number. Next, since the constituent tissues of the subject are classified based on the morphological image measured by the X-ray CT, a numerical value that can be determined in advance among the above optical variables is given as a constant.
For example, if the wavelength of light used for measurement is set to a wavelength of 600-700 nm, mi = 0 should be set because there is almost no substance that absorbs light of 600-700 nm in the bone region in the image of the head. Can be. The scattering coefficient of the bone varies depending on the age of the subject, but can be estimated from conventional measurement data. If a standard numerical value of the scattering coefficient in the bone at each age is obtained, the scattering coefficient si in the bone region can be given as a constant. Further, for each tissue in the brain, a scattering coefficient is experimentally obtained in advance in accordance with the above-described tissue classification, and is set based on a standard value. As a result, the only true variable of the measurement area required for imaging is the absorption coefficient mi in the brain tissue.

By the above processing, many parts of the combination of variables originally given to each area can be set in advance, so that the subsequent imaging is easy and the time required for calculation can be shortened.

Next, a method for obtaining the distribution of the absorption coefficient based on these variables and the set constant distribution will be described below.

When there is a subject, the measured value obtained when assuming a certain light emitting point Sk is a combination of the measurement locations Ak1 obtained at each detection point as shown in FIG. 9B.

The light emitted from the light irradiation section Sk diffuses from the end face of the fiber and enters each detector. Therefore, the data is input to each of the detectors when there is no subject. Therefore, the above measured values when there is no subject are set to Ak10. Note that this measurement value is not time gated.

From the above data, Xk1 = −log (Ak1 / Ak10) (1) is obtained. Here, it can be considered that the light that has passed through the time gate has almost traveled straight in the living body, so that a region Rkl through which the light passes can be obtained from the combination of k and 1 as shown in FIG. 9C. A set of numbers of all pixels included in the area is R. At this time, the absorbance Xk1 obtained from the measured value is as follows: Xk1 = Σ (mi + si), i∈R (2) Of these, si is known, so the attenuation due to true absorption in each measurement unit can be determined by Yk1 = Xk1-Σ (si), i∈R. When the pixel i is included in the bone region, mi = 0 can be set. Further, the above calculation is performed for all combinations of k and 1.
As a result, a combination of projections (Yk1, k = 1 to Ns, 1 = 1 to Nd) of the absorption value mi is obtained, and the algorithm of CT image reproduction in the conventional X-ray CT is applied to apply the absorption value (mi). ) Is required.

By the above arithmetic processing, an image showing the spatial distribution of the light absorption coefficient at a specific wavelength (that is, the spatial distribution of a specific metabolite) as shown in FIG. 9D is obtained. Here, a tissue discrimination image has been obtained by the morphological measurement device. The positional relationship between the two images is accurately correlated, as is clear from the previous processing. Therefore, effective diagnostic information can be given even if these two images are displayed in parallel. However, the morphological image shows only a boundary portion of each tissue with a specific color on one CRT, and a grayscale image of the function ( If b) is displayed in a density or hue using a color different from the boundary display, the actual state of the biological function is accurately displayed, and information can be optimally provided for diagnosis. FIG. 9D shows an example of such a display.

As a functional image display, if the deviation from a standard value obtained from a medical point of view is displayed as a density instead of displaying the absolute value of the measured physical quantity, it is more medically effective. Information can be given. It is more preferable that the standard value be a value corresponding to an organ or tissue obtained from a morphological measurement image.

Although the above embodiment is an example in which a living body optical imaging device is used for the function measuring section, the following general processing can be performed when a general arbitrary function measuring method is used.

First, a method of measuring a physical quantity for displaying a biological function and forming an image needs to have the following procedure.

(1) Receive a signal from a limited portion of the measurement area. This signal reflects the influence of the physical quantity on a limited portion of the measurement area.

(2) The limited area (scanning area) is moved to the entire area of the subject to measure a signal (measurement area scanning).

The time order of the area scanning is set to 1.2. .
Assuming that i, Nm (Nm: the number of measurements), measured values Xi (i = 1 to Nm) are obtained according to the respective numbers. Further, a measurement region Ri (i = 1 to Nm) corresponding to each measurement number is designated in the measurement region.

Therefore, the measurement area is first divided into pixels of an appropriate size, and this is defined as hj (j = 1 to NpNp: number of pixels).

Incidentally, such a measurement is of course intended to measure a specific physical quantity. However, since a weak signal is handled particularly in a measurement intended for a functional measurement, the measured signal is a physical quantity to be obtained. (In the case of optical measurement, for example, absorption coefficient) In addition to the above, there are many cases where a variation due to another physical quantity occurs. For example, the effect of scattering in optical measurement is an example of such a displacement. Therefore, the measured value Xi can be displayed as follows: Xi = f (ak..., Bk... Ck) k∈Ri (3) A is the physical quantity to be obtained,
b and c are physical quantities that cause mutation. f is a function relating these. Here, when there is a relationship such as Expression (3), it is necessary to calculate the values of all variables a, b, and c to calculate the measurement target physical quantity ak of each pixel. In general, such calculation requires a huge amount of calculation and is often impossible in practice.

By the way, according to the apparatus of the present invention, the form of the object to be measured can be measured at exactly the same position before or after the function measurement. Thereby, the outer shape of the measurement object and the distribution shape of the internal tissue can be measured. By adding the position display as described above, the measurement area in the function measurement can be accurately associated with the morphological measurement image.

Next, among the physical variables (a, b, c), the variable to be obtained is a, which is generally unknown. However, the physical properties of living organisms depend on the type of living tissue. The type of the living tissue can be identified on the morphological measurement image from the anatomical knowledge. In the above embodiment, an example of discriminating bone and brain tissue in the head is shown.

The scattering coefficient in optical measurement is an example of such a physical quantity that can be estimated, and in magnetoencephalography, the permeability of tissue corresponds to PET, and the absorption coefficient of annihilation gamma rays corresponds to these in PET. In each of these, a standard numerical value can be applied corresponding to a tissue type that can be classified by morphometry. In other words, the variable a, which is the purpose of measurement, is a true variable, and other variables b (which can be estimated by the form) depending on the form,
c is set to an estimated value, and the above equation (3) becomes Xi = f (ak...) k∈Ri (4), which solves the problem of the conventional image reproduction using one physical variable. I can return.

The image reproduction can be performed by using the image reproduction method in the conventional X-ray CT or the iteration method from the combination of the variables thus simplified.

Further, by displaying the distribution image of the function obtained by the above calculation and the already obtained morphological image in a superimposed manner as described above, effective diagnostic information can be given.

Since the measured physical quantity a is also a physical quantity in a living body, the range or average value may be limited depending on the tissue. In such a case, the estimated value of ai is calculated as a
By setting aj = aj0 + dai as i0, an operation using dai as a variable can be performed. In this case, “dai” has a small value. Therefore, in the image reproduction process, the calculation time can be reduced and the accuracy can be improved as compared with the case where ai is a variable.

[0087]

As described above, according to the present invention, by integrating the morphological measurement unit and the function measurement unit, the morphological information obtained from the morphological image is used for reproducing the function distribution image. Accurate functional images can be obtained at a high rate.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 shows the appearance of an embodiment of the present invention.

FIG. 3 is a diagram showing a measurement area in the embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a biological light imaging unit according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a biological light imaging unit according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a state of a measurement signal of the living body optical imaging section of the present invention.

FIG. 7 is a diagram showing a measurement image in the form measurement unit according to the embodiment of the present invention.

FIG. 8 is a diagram showing a measurement sequence according to the embodiment of the present invention.

FIG. 9 is a diagram showing a process of processing measurement data.

Continuing from the front page (72) Inventor Takeshi Tajima 1-280 Higashi-Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-57-115232 (JP, A) JP-A-4-1055641 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 10/00 A61B 5 / 055 A61B 6/03 360

Claims (6)

(57) [Claims] 1. A living body measuring apparatus having a form measuring means for measuring a shape of a living body and a function measuring means for measuring a function of the living body, wherein the function measuring means irradiates light to a plurality of positions of the living body. Means, detecting means for detecting light radiated by the irradiating means and passing through the living body, and image creating means for creating a spatial distribution image of the biological function from function measurement data, wherein the image creating means comprises the morphological measurement A living body measuring device for creating the spatial distribution image using the morphological information obtained by the means. 2. The image forming device according to claim 1 , further comprising a display unit that generates a morphological image from the morphological information obtained by the morphological measuring device, and displays the morphological image and the measured image in a superimposed manner. The biological measurement device according to claim 1. 3. The biometric device according to claim 2, wherein the morphological image and the functional image are displayed in different colors. 4. The apparatus according to claim 1 , further comprising a cap with a marker for accommodating said irradiating means and said detecting means.
4. The biological measurement device according to any one of items 1 to 3. Wherein said form measuring means, biological measurement apparatus according to claim 1, characterized in that the X-ray CT apparatus 3. Wherein said form measuring means, biological measurement apparatus according to any one of claims 1 to 3, characterized in that the MRI apparatus.