JP2008079835A - Tumor detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tumor detection device capable of accurately detecting presence of malignancy. <P>SOLUTION: The tumor detection device comprises an image obtaining means 1 to obtain a biological image of an inside of a living body, an extracting means 2 to extract a suspected tumor region based on the biological image, a first light having a first wavelength of a light absorption band of a benign tumor in the inside of the living body, an irradiation means 3 to irradiate a beam of second light having a second wavelength of a light absorption band of a malignant tumor, a detection means 4 to detect an outgoing beam from inside of the living body based on the irradiation means 3, and a determination means 5 to analyze of optical powers in the first and second wavelengths of the outgoing beam and to determine a category of cellular structure of the region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tumor detection apparatus that can be used for early detection of malignant tumors.

Conventionally, as a technique for noninvasively measuring a tumor in a living body, for example, a biological tissue morphological image obtained by ultrasonic echoes and a concentration distribution of hemoglobin or the like obtained by light irradiation / photoacoustic signal detection on the biological tissue A technique is disclosed in which an image is superimposed and whether or not the biological tissue is a tumor is determined based on a morphological structure, a distribution of a concentration of hemoglobin, or the like (for example, Patent Document 1).
JP 2005-218684 A

However, the technology for imaging the inside of a living body using light irradiation has the property that the light entering the living body causes strong scattering because the living body is composed of a collection of minute regions having different refractive indexes. There is a problem that the spatial resolution is lowered. Further, when calculating position information from the detection result of reflected light, in order to obtain correct information, it is necessary to calculate a large amount of data with a complicated algorithm. Furthermore, in the technology using photoacoustics, a piezoelectric vibrator such as a microphone or PZT is usually used for detecting an acoustic signal. However, an acoustic signal at a level that does not damage the living body is very weak, and there is a problem that sufficient signal detection ability cannot be obtained even if processing such as addition averaging by repeated measurement is performed. Furthermore, in the morphological structure and hemoglobin concentration distribution, the point of discriminating whether or not it is a tumor is inevitably dependent on past results and experience, so there is a limit to accurately detecting only malignant tumors. .
Then, an object of this invention is to provide the tumor detection apparatus which can detect the presence or absence of a malignant tumor correctly.

The tumor detection apparatus according to the present invention includes an image acquisition unit that transmits and receives ultrasonic waves to acquire a living body image inside the living body, an extraction unit that extracts a portion suspected of being a tumor based on the living body image, and the inside of the living body A first light having a first wavelength of a light absorption band of a benign tumor, an irradiation means for irradiating a second light having a second wavelength of a light absorption band of a malignant tumor, and the irradiation means based on the irradiation means Detection means for detecting light emitted from inside the living body, and determination means for analyzing a change in light intensity of the emitted light at the first and second wavelengths to determine the type of cellular tissue at the site. It is characterized by that.

ADVANTAGE OF THE INVENTION According to this invention, the tumor detection apparatus which can detect correctly the presence or absence of a malignant tumor is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description of the drawings, the same portions are denoted by the same reference numerals, and overlapping descriptions are omitted. The drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, there are included portions having different dimensional relationships and ratios between the drawings.

FIG. 1 is a block diagram showing a schematic configuration of the entire tumor detection apparatus according to an embodiment of the present invention.

As shown in FIG. 1, a tumor detection apparatus according to an embodiment of the present invention includes an image acquisition unit 1 that transmits and receives ultrasonic waves to acquire a living body image inside a living body, and a suspected tumor based on the living body image. Extraction means 2 for extracting a region of interest, first light having a first wavelength of a light absorption band of a benign tumor inside the living body from which the biological image was acquired, and a second light absorption band of a malignant tumor Irradiation means 3 for irradiating second light having a wavelength, detection means 4 for detecting emitted light from the inside of the living body based on the irradiating means 3, and light at the first and second wavelengths of the emitted light Determination means 5 for analyzing the intensity change and determining the type of cellular tissue of the region of interest.

The image acquisition means 1 includes an ultrasonic transmission / reception unit 10 that transmits / receives ultrasonic waves to / from the living body 50, and a first calculation circuit 11 that calculates a biological image inside the living body 50 by analyzing a signal received by the ultrasonic transmission / reception unit 10.
And.

The extraction unit 2 includes a second arithmetic circuit 12 that extracts a region of interest suspected of being a tumor based on the biological image acquired by the image acquisition unit 1. The analysis of the biological image by the second arithmetic circuit 12 analyzes the presence / absence of an area having a lower echo level than the surroundings (a black area in the biological image, hereinafter referred to as a low echo area) due to a contrast difference on the biological image.

  FIG. 2 is a reference biological image for explaining the analysis method of the extraction means 2.

The living body image acquired by the image acquisition means 1 is detected by detecting the boundary line between the high echo level area Hc (white area in the living body image, hereinafter referred to as high echo area) and the low echo area Lc. To extract. Here, the high echo area Hc is an area where the ultrasonic echo level is high, and the low echo area Lc is an area where the echo level is low. In particular, in the case of a tumor such as breast cancer, the ultrasonic echo level is low compared to the surrounding mammary gland and often differs from the surrounding contrast. Therefore, in the biological image in the ultrasonic measurement, the low echo area Lc can be extracted as a site of interest suspected of being a tumor (dotted line portion in FIG. 2).

Further, in a biological image in ultrasonic measurement, the texture on the image is often different between the tumor and its periphery due to the difference in tissue shape. Therefore, a region different from the surroundings may be analyzed based on the difference in texture on the biological image obtained by ultrasonic measurement, and the region may be extracted as a region of interest suspected of being a tumor.

It should be noted that the region of interest extracted by the extracting means 2 cannot be determined to be any tissue at this stage. At this point, this extracted site of interest is a fat cell benign tumor (cyst, adenoma, etc.)
And malignant tumors (hard cancer, solid ductal cancer, etc.).

It should be noted that there is a case where the region of interest cannot be extracted only by the difference in contrast and texture in the extraction of the region of interest by the extraction means 2. The ultrasonic measurement described above is a method of generating a contrast difference of an image from a difference in acoustic impedance for each tissue of a living body. However, depending on the tumor, there is rarely a case where the acoustic impedance is close to that of the surrounding normal tissue. In this case, extraction cannot be performed due to a difference in contrast or texture on a biological image in ultrasonic measurement. Similarly, breast cancer of a type that does not form a tumor may not be extracted from a difference in contrast or texture on a biological image obtained by ultrasonic measurement.

In this way, when the region of interest is not extracted from the contrast difference or texture difference on the biological image, the presence or absence of the boundary line breakage at the interface near the skin on the biological image and the back echo area in the biological image The presence or absence of a high echo area is analyzed.

FIG. 3 is a reference biometric image for explaining the analysis of the presence or absence of a break in the boundary line generated at the interface near the skin on the biometric image.

The analysis of the presence or absence of the break of the boundary line is performed by analyzing the linear high echo portion 60 generated near the skin on the living body image,
The linear high echo portion 60 shown in FIG. 3 (a) has a small change in the echo level in the horizontal direction. In addition, the linear high echo part 61 shown in FIG.3 (b) has the change of an echo level large in the horizontal direction (especially B vicinity). In this case, as shown in FIG. 3B, when the change in the echo level in the lateral direction is large, it is determined that there is a break in the boundary line generated at the interface near the skin on the biological image.

FIG. 4 is a reference biological image for explaining the analysis of the presence or absence of the high echo area in the rear echo area in the biological image. In the analysis of the presence or absence of the high echo area in the rear echo area C in the biological image, the contrast difference in the rear echo area C is analyzed, and the presence or absence of a portion having a higher echo level than the surrounding area is analyzed.

In this way, the boundary line breakage occurring at the interface in the vicinity of the skin of the biological image and the rear echo area C
If there is a high echo portion, the region between them is determined as a region of interest and extracted (dotted line region in FIG. 5).

In this way, the presence or absence of a high-echo area in the rear echo area and the break of the boundary line occurring at the interface near the skin on the biological image are evaluated, and if both exist, the area between them is determined as the site of interest. The reason is as follows.

Even if the tumor has the same acoustic impedance as that of the tissue of the surrounding living body, the periphery of the area where the tumor exists has some influence as compared with normal cells. For example, tumors absorb nutrients in the body and become enlarged. This enlargement gives stress to the arrangement state of surrounding normal cells and changes the arrangement state. Therefore, by analyzing the situation of the part located in the periphery of the tumor, the presence can be detected even in the tumor having the same acoustic impedance as that of the surrounding living cells.

As described above, since the region of interest extracted here has no contrast with the mammary gland, fat is excluded and classified into two types, a benign tumor and a malignant tumor.

The irradiation unit 3 includes an optical signal transmission unit 13, a light source unit 14, an optical multiplexing unit 15, an optical waveguide unit 16, and a light irradiation unit 17.

The optical signal transmission unit 13 has a function of transmitting a signal for controlling the wavelength, intensity, and the like of light applied to the living body, and is configured by a signal transmitter, for example.

The light source unit 14 detects a signal transmitted from the optical signal transmission unit 13 and generates a first light having a first wavelength in a light absorption band of a benign tumor, and a malignant tumor And a second light source 14b for generating second light having a second wavelength in the light absorption band. Light source 14a
, 14b is preferably a light emitting element such as a semiconductor laser (LD), a light emitting diode (LED), a solid state laser, or a gas laser. The first light absorption band of benign tumor here
Is a wavelength band of 980 nm, for example. Moreover, the 2nd wavelength of the light absorption band of a malignant tumor here is a wavelength band of 760 nm, for example.

The optical multiplexing unit 15 includes first and second optical units generated by a plurality of (two in the present embodiment) light source units 14.
For example, a collimating lens and a right-angle prism or a dichroic prism.

The optical waveguide unit 16 is for guiding the first and second lights combined by the optical combining unit 15 to the living body 50. For example, an optical fiber or a thin-film optical waveguide is used for efficient light propagation. It is also possible to propagate directly in space.

The light irradiation unit 17 is configured by an end of the optical waveguide unit 16 and irradiates the light propagated from the optical waveguide unit 16 by directly or indirectly contacting the living body 50.

  The detection unit 4 includes a light detection unit 18, an optical waveguide unit 19, and an optical analysis unit 20.

The light detection unit 18 directly detects or indirectly detects the light emitted from the living body 50 based on the light irradiation from the light irradiation unit 17. The light detection unit 18 includes, for example, end portions of a plurality of optical fibers.

The optical waveguide unit 19 is for guiding outgoing light detected by the light detection unit 18 to an optical analysis unit 20 to be described later. For example, the optical waveguide unit 19 is composed of an optical fiber or a thin-film optical waveguide for efficient light propagation. However, direct spatial propagation is also possible.

  The ultrasonic transmission / reception unit 10, the light irradiation unit 17, and the light detection unit 18 constitute a measurement unit 30.

  FIG. 6 shows a cross-sectional configuration diagram of a specific configuration in the measurement unit 30.

As shown in FIG. 6, the ultrasonic transmission / reception unit 10 includes a backing member 51 and a backing member 5.
1, a desired space 52, and a plurality of channels 53 arranged in a two-dimensional direction. The plurality of channels 53 include a plurality of piezoelectric elements 54 provided on the backing member 51, an acoustic matching layer 55 provided on the piezoelectric elements 54, and an acoustic matching layer 55.
And an acoustic lens 56 provided above. The backing member 51 and the piezoelectric element 54, the piezoelectric element 54 and the acoustic matching layer 55, and the acoustic matching layer 55 and the acoustic lens 56 are bonded and fixed by an epoxy resin adhesive (not shown). Has been.

The piezoelectric element 54 includes, for example, a piezoelectric body 54a made of a lead zirconate titanate (PZT) -based piezoelectric ceramic material or a relaxor-based single crystal material, and a first electrode 54b and a second electrode 54b formed on both surfaces of the piezoelectric body 54a. It is comprised with the electrode 54c.

The acoustic matching layer 55 is provided on the second electrode 54c of the piezoelectric element 54 so that the acoustic impedance gradually decreases from the piezoelectric element 54 to the acoustic lens 56, for example, and the acoustic impedance is 10 to 15 MRayls at 25 ° C. A first acoustic matching layer (not shown), a second acoustic matching layer (not shown) provided on the first acoustic matching layer and having an acoustic impedance of 2.7 to 8.0 MRayls at 25 ° C., a second acoustic The third acoustic matching layer (provided on the matching layer and in contact with the acoustic lens 56 and having an acoustic impedance of 1.6 to 2.5 MRayls at 25 ° C.)
(Not shown).

In addition, a control circuit for controlling the driving timing of the piezoelectric element 54 is provided in the plurality of channels 53 (
A signal processing circuit (not shown) including an amplifier circuit for amplifying a received signal received by the piezoelectric element 54 is connected to the piezoelectric element 54. The first and second electrodes 54 b and 54 c of the piezoelectric element 54 are connected to an extended signal line and a ground line (not shown), which are in a direction opposite to the acoustic lens 56. And connected to a control circuit (not shown).

In the ultrasonic transmission / reception unit 10 having such a configuration, a voltage is applied between the first electrode 54b and the second electrode 54c of the piezoelectric element 54 to resonate the piezoelectric body 54a, whereby the acoustic wave of each channel 53 is obtained. Ultrasound is transmitted into the living body 50 through the matching layer 55 and the acoustic lens 56.
When receiving the ultrasonic wave transmitted into the living body 50 from the living body 50, the ultrasonic wave received through the acoustic lens 56 of each channel 53 and the acoustic matching layer 55 is vibrated in the piezoelectric body 54a of each channel 53. The vibration is converted into an electric signal and transmitted to the first arithmetic circuit 11. Although not shown, the space 52 is filled with a relatively soft resin such as low acoustic impedance and high attenuation silicone rubber to increase the mechanical strength of the ultrasonic transmission / reception unit 10. It may be held.

As shown in FIG. 6, the optical waveguide unit 16 and the light irradiation unit 17 have a configuration in which, for example, a single unit is arranged in the space 52 of the ultrasonic transmission / reception unit 10.

As shown in FIG. 6, the light detection unit 18 and the optical waveguide unit 19 have a configuration in which, for example, a plurality of light detection units 18 and optical waveguide units 19 are arranged in the space 52 of the ultrasonic transmission / reception unit 10.

The light analysis unit 20 analyzes the light intensity change of the first and second wavelengths of the light detected by the light detection unit 18. The light intensity change information analyzed by the light analysis unit 20 is output to the determination unit 5 described later.

  The determination means 5 is composed of a third arithmetic circuit 21.

The third arithmetic circuit 21 analyzes the light intensity change information output from the light analysis unit 20 and determines a cell (a normal cell, a benign tumor, or a malignant tumor) of the region of interest.

Specifically, when the light intensity change at the first wavelength of the light detected by the light detection unit 18 is large (specifically, the light intensity is smaller than that at the time of irradiation), the extracted region of interest is “benign tumor”. If the light intensity change at the second wavelength of the light detected by the light detection unit 18 is large (specifically, the light intensity is smaller than that at the time of irradiation), the extracted region of interest is determined as a “malignant tumor”. The
When the light intensity changes at the first and second wavelengths of the light detected by the light detection unit 18 are both small, the extracted region of interest is determined to be “fat”.

Here, “the light intensity change is large” and “the light intensity change is small” vary greatly depending on each individual measurer and also on each measurement site. Therefore, the light intensity change of each of the benign tumor and the malignant tumor is measured in advance in a sample different from the living body 50, or the amount of change in the light intensity in the part where the fat, benign tumor and malignant tumor of the living body 50 itself does not exist Is taken as a reference value, taking into account variations in individual differences, and if a change in light intensity exceeding the reference value is detected, it is assumed that the light intensity change is large and the reference value May be defined as “light intensity change is small”.
Furthermore, there is a wavelength at which absorption occurs in both benign and malignant tumors, and the two can be distinguished by the magnitude of the absorption.

By analyzing the light intensity change by the above method, the extracted cellular tissue of the region of interest is determined.

The determined cellular tissue of the region of interest is displayed as a tumor test result on, for example, the display unit 22 attached inside or outside the tumor detection apparatus as a character on the biological image from which the region of interest has been extracted.

In addition, as shown in FIG. 1, the living body 5 connected to the light analyzing unit 20 and detected by the light detecting unit 18.
The first and second lights of the light sources 14a and 14b of the light source unit 14 are detected so as to detect temporal changes in the light intensity at the first and second wavelengths of the emitted light from 0 and cancel the temporal changes. A light intensity adjusting unit 23 for adjusting the intensity of the light may be provided.

In the tumor detection apparatus according to the embodiment of the present invention, the optical multiplexing unit 15 and the light intensity adjustment unit 23 described above are not essential components, but in the present embodiment, it is more preferable to have this configuration. Needless to say, the tumor can be detected with high accuracy.

Next, the tumor determination process according to the present embodiment will be described. FIG. 7 is a process flow diagram illustrating a tumor determination process according to the present embodiment.

As shown in FIG. 7, first, a biometric image is acquired by the image acquisition means 1 (S100).
Next, the presence / absence of a region of interest suspected of being a tumor is analyzed using a contrast difference or a texture difference on the obtained biological image (first analysis means: S101). In this first analysis means, when it is determined that there is a region of interest in the living body image, the optical constant of each tissue of benign tumor and malignant tumor is applied to the region of interest, and the diffusion equation shown below or Monte Carlo simulation or the like A theoretical value of the light intensity detected by the light detection means is calculated using a statistical method (theoretical value calculation means: S102).

An example of the theoretical value calculation means S102 is shown below. 8 to 10 show the theoretical value calculation means S1.
An explanatory view for explaining 02 is shown. In these figures, the explanation is easy to understand.
The subscript has been changed from the Excel test version. (Coordinate direction follows Fig. 8)

The target organization (subscript 2) exists in the surrounding organization (subscript 1), and each equation is

D is the diffusion coefficient, φ is the light intensity [W / mm ² ], μ _a is the absorption coefficient [mm ⁻¹ ], S is the term corresponding to the light source,
Radiation energy per unit volume and unit time [W / mm ³ ] (S is not present in the target tissue). The diffusion coefficient D is expressed by the following formula.

g is a coefficient called anisotropic scattering parameter [dimensionless], and μ _s is a scattering coefficient [mm ⁻¹ ]. This time, it is assumed that the scattering coefficients of the surrounding tissue and the target tissue are the same.
(1) S in the formula is represented by the following formula.

I ₀ is the incident radiant flux [W] (continuous light this time), a is the incident light radius [mm] (optical fiber radius), δ
Is a delta function [mm ⁻¹ ], and θ is a snake side function [dimensionless]. z ₀ [mm] is expressed by the following formula.

k _a is a correction coefficient.
The boundary condition from the analysis region (surrounding tissue) to the outside is

k _b is a correction coefficient. For n, the direction from the inside of the surrounding tissue to the outside of the analysis region is positive.

The boundary condition between the surrounding tissue and the target tissue is expressed by the following equation.

From the above, the radiant flux I at the detection location is obtained by the following equation.

B is a disc region having an incident light radius a centered on the detection position coordinate.

Using equation (10), R = [radiant flux I at the detection point] / [incident radiant flux I ₀ ] is calculated.

<Typical input values>
Absorption coefficient of target tissue μ _a1 = 0.0041 [mm ^-1 ]
Absorption coefficient of surrounding tissue μ _a2 = 0.01 [mm ^-1 ]
Scattering coefficient μ _s = 11 [mm ^-1 ]
Optical fiber diameter 2a = 0.8 [mm]
Anisotropic scattering parameter g = 0.75
Correction factor k _a k _a = 0.7
Correction factor k _b k _b = 1

<Reference: Analytical solution in infinite space>
When there is no target tissue in a typical input value = when the absorption coefficient of the target tissue is 0.01 [mm ⁻¹ ] Incident-detection distance R
10mm 9.16 × 10 ^-6
20mm 3.00 × 10 ^-7

Next, the difference between the theoretical value of each of the benign tumor and the malignant tumor calculated by the theoretical value calculating means S102 and the actually measured value of the light intensity at the first and second wavelengths detected by the detecting means is calculated ( Difference calculation means: S103). Next, each calculated difference is compared with the threshold value by using the range of the measurement variation of the light intensity detected by the light detection means measured in advance as a threshold value (first threshold value comparing means: S104). The “range of measurement variation of the light intensity detected by the pre-measured light detection means” described here is the “measurement variation range” (maximum value−minimum value) of the unique measurement value in the apparatus. ). The “measurement variation range” is the maximum value −
It is not limited to the minimum value. For example, in a reference sample or the like, the same location is continuously measured, and the maximum value within the range of 3σ (σ: standard deviation) with respect to the average value of the measured values. Value-minimum value may be used. Since the range of this measurement variation is a machine-specific variation that varies depending on the individual subject, the device, etc., it is preferable that measurement is performed in advance in a portion where there is no fat, tumor, etc. .

Next, when the difference is equal to or smaller than the threshold value (difference ≦ threshold value) in the first threshold value comparison means (S104), it is determined that each calculated theoretical value matches the actual measurement value, and the corresponding organization satisfying this relationship It is determined that either (benign tumor or malignant tumor) is present (first determination means: S105).
Further, when the difference is larger than the threshold value in any tissue by the first threshold value comparison means (S104) (difference> threshold value), it is determined that the region of interest is not the corresponding tissue (benign tumor or malignant tumor) ( Second determination means: S106).

Next, if the first analysis unit determines that there is no region of interest in the biological image, or if the difference is larger than the threshold value in any tissue by the first threshold comparison unit, the biological image is not covered. When the presence or absence of a boundary line occurring near the skin of the specimen and the presence or absence of a high echo area in the rear echo area of the biological image are analyzed (second analysis means: S107), and there is a boundary line break and a high contrast area First, a region between the boundary line and the high echo region is extracted as a region of interest (S108). The horizontal width of the high echo area at this time is the width of the region of interest. The region of interest extracted at this point is either a benign tumor or a malignant tumor.

Next, when it is determined in the second analysis means that the region of interest exists, the optical constant of each tissue of benign tumor and malignant tumor is applied to the region of interest, and the diffusion equation described above or
A theoretical value of each light intensity detected by the light detection means is calculated using a statistical method such as Monte Carlo simulation (theoretical value calculation means: S109).

Next, the respective theoretical values calculated by the theoretical value calculating means 109 and the first values detected by the light detecting means.
And the difference with the measured value of the light intensity at the second wavelength is calculated (difference calculating means: S110). Next, a difference between the calculated difference and the threshold is compared using a range of measurement variations of the light intensity detected by the light detecting means measured in advance as a threshold (second threshold comparing means: S111).

When the difference is less than or equal to the threshold value by the second threshold value comparison means (difference ≦ threshold value), it is determined that each calculated theoretical value matches the actual measurement value, and the corresponding tissue satisfying this relationship (benign tumor or malignant tumor) ) Is present (third determination means: S112). Further, when the difference is larger than the threshold value in any tissue by the second threshold value comparison means (difference> threshold value), it is determined that the region of interest is not the corresponding tissue (benign tumor or malignant tumor) (fourth) Determination means: S11
3).

If it is determined by the second analysis means (S107) that there is no region of interest, it is determined that there is no corresponding tissue (benign tumor or malignant tumor) in the measurement region (fifth determination means: S114).
).

Thus, the tumor detection device according to the present invention acquires a biological image by transmitting and receiving ultrasonic waves,
A region of interest suspected of being a tumor is extracted from the acquired biological image, a first light having a first wavelength of a light absorption band of a benign tumor, and a malignant tumor with respect to the measurement region having the extracted region of interest The region of interest extracted by irradiating the second light having the second wavelength in the light absorption band and analyzing the change in the light intensity of the first and second wavelengths of the emitted light from the inside of the subject. Since it is possible to determine the type of cell tissue, it is not necessary to perform mammography or other diagnostics, and the presence or absence of a tumor can be detected non-invasively with little physical damage to the measurement site of the living body. it can.

Furthermore, when determining the type of cellular tissue of the detected region of interest, the optical light intensity theoretical value is calculated in advance, the difference from the actual measured value is calculated, and the difference in measurement variation peculiar to the device is calculated. As the threshold value, the calculated difference is compared with the threshold value, and the type of cell tissue is determined according to the comparison. Therefore, the determination process can be performed in consideration of the measurement variation unique to the optical diagnostic apparatus. The type of organization can be determined.

In the light irradiation means described above, the first light having the first wavelength of the light absorption band of the benign tumor and the second light having the second wavelength of the light absorption band of the malignant tumor are irradiated. As described above, in addition to this, the third light having the third wavelength in the light absorption band of fat is further added, and the region-of-interest determination means analyzes the third light intensity change to analyze the region of interest. The type of cell tissue may be determined.

That is, the theoretical value is also calculated for the fat by the theoretical value calculating means, the difference is also calculated for the fat by the first and second difference calculating means, and the difference and the threshold value are also calculated for the fat by the first and second threshold comparing means. And the presence or absence of fat may be determined by the first to fifth determination means. In this case, the third wavelength of the fat light absorption band is, for example, a wavelength band of 930 nm.

(Example 1)
Phantoms that model fat, benign tumors, and malignant tumors were prepared.

A block made of agar, with scatterers (10% fat globule dispersion, product name: Intralipid) and absorbers (charcoal powder and ink) dispersed and hardened to have the same acoustic characteristics and optical constants as the mammary gland It was. While a thin plate obtained by slicing the block into 5 mm was prepared, a groove having a width and length of 5 to 25 mm (in increments of 5 mm) and a depth of 5 mm was formed on the block surface.

As a model tumor component, the near-infrared region of hemoglobin reduced form and hemoglobin oxidized form (80
Each dye was selected to show a spectrum that coincided with the absorption spectrum (near 0 nm), and two types of aqueous solutions were prepared (model 1: aqueous solution of hemoglobin reductant, model 2: aqueous solution of hemoglobin oxidant). In these two types of models, the concentrations of the model aqueous solution 1 and the model aqueous solution 2 were adjusted according to literature values. After agar was dispersed in these aqueous solutions, it was poured into a groove on the block and hardened to obtain models of fat, benign tumor and malignant tumor. After putting a thin plate on the block, it was stuck so that an air layer was not formed.

Combined with the absorption bands of hemoglobin reductant and hemoglobin oxidant, the measurement wavelength is 760 nm, 8
40 nm, and two near-infrared LDs (intensity-modulated continuous wave LDs with sine waves of 600 kHz and 700 kHz) were selected as light sources. The modulated light output from each LD was combined on the filter, and the sample was irradiated with light through one optical fiber (quartz single core, 250 μm diameter). On the other hand, outgoing light is transferred by optical fiber (plastic multi-core, 500 μm diameter), and light detection is performed by a system (OE detector, which can detect output from sub nW to 10 mW) connected to a logarithmic amplifier with a fast response Si photodiode. did. An integrated probe shown in FIG. 2 was manufactured by installing an optical fiber so as to follow the acoustic element of the ultrasonic probe having a center frequency of 8 MHz. Because the depth information obtained depends on the distance between the input fiber and the output fiber,
Outgoing fibers were arranged in 10 mm increments from the incident fiber, and were put together in a protective tube into a tape shape. The position of the acoustic element end, the incident fiber, and the output fiber were aligned and fixed. OE
The output of each LD can be detected independently by applying an external trigger with a signal to the LD driver. The output from the lock-in amplifier was further amplified by the main amplifier and then AD converted to be taken into the PC.

First, the light output from each LD was detected with a lock-in amplifier in a state where the probe was put on the position where there was no groove, and the light intensity passing through the mammary gland model without the absorber was measured. The current value supplied to the LD was adjusted so that the two LD outputs were of the same level (10 nW to sub-μW level). In this state, contrast contrast was not seen in the biological image.

The probe was rotated around the position of the source fiber until the probe passed over the grooved location and again over the grooveless location. This corresponds to changing only the position of the detector without changing the position of the light source, and was performed in order to keep the light incident condition as constant as possible. The probe was rotated in 15 degree increments. The average value of the measured values at 0 ° and 180 ° is used as the optical measurement result (reference value) when there is no absorber, and the value obtained by dividing the measurement result at each position by this reference value is transmitted through the absorber. The light intensity.

In the part where the fat model was put in the groove, the groove was observed as a low contrast image in the living body image.
An image of the groove portion was extracted using the difference in contrast with the groove periphery. 760 nm as an optical constant
・ Use the literature values (reference: Phys. Med. Biol. Vol.35, 1317-1334 1990) of the mammary gland, fat, benign tumor, malignant tumor, and equivalent scattering coefficient at 840 nm. The light diffusion equation was solved assuming that there were compounds of fat, benign tumor and malignant tumor in the mammary gland and groove, and the light intensity at each detection position of 5 mm to 50 mm was calculated. These calculated values and measured values (respectively relative to the reference value, reference value in the case of actual measurement: measured value at the position where there is no absorber, reference value in the case of calculation: the optical constant of the mammary gland is also applied to the groove part) Calculated value)
As a result, it was found that the difference with the calculated value when fat was assumed was the smallest. And since this difference is smaller than the threshold value for determining that it matches,
The calculated value and the actually measured value were determined to be the same, and the compound in the groove was determined to be fat.

(Example 2)
Using the probe used in Example 1, the breast of a volunteer (44 years old, female, BMI = 19, healthy person diagnosed as not suffering from breast cancer) was measured. 0 for both breasts
Measurements were made at 8 points from 45 degrees to 45 degrees. Probe tip (side with incident fiber)
Was placed directly under the teat and the probe was placed in the radial direction. In the living body image, a low echo area (circular shape) was observed in the mammary gland. The hypoechoic region was extracted from the difference due to contrast, and the surrounding area was assumed to be a uniform mammary gland. Using optical values of literature values of absorption coefficient and equivalent scattering coefficient of breast, fat, benign tumor, and malignant tumor at 760 nm and 840 nm, assuming that there is a compound of fat, benign tumor, and malignant tumor in the mammary gland in the background and the circular part Solve the light diffusion equation,
The light intensity at each detection position of 5 mm to 50 mm was calculated. These calculated values and measured values (respectively relative to the reference value, reference value in the case of actual measurement: measured value at the position where there is no absorber, reference value in the case of calculation: apply the optical constant of the mammary gland to the circular part) When the calculated values were compared, it was found that the difference between the calculated values and the benign tumors was the smallest. And since this difference became smaller than the threshold value for determining that it was in agreement, it was determined that the calculated value and the actually measured value were in agreement, and the compound in the circular region was determined to be a benign tumor. The diagnosis by the doctor was a cyst that was a benign tumor, which was consistent with the determination by optical measurement.

The block diagram which shows schematic structure of the whole tumor detection apparatus which concerns on one Embodiment of this invention. The reference biological image for demonstrating the analysis method of the extraction means 2. FIG. The reference biological image for demonstrating the analysis of the presence or absence of the break of the boundary line which generate | occur | produces in the interface of skin vicinity on a biological image. The reference biological image for demonstrating the analysis of the presence or absence of the high contact area | region in the back echo area | region in a biological image. The reference biological image for demonstrating the analysis of the presence or absence of the high contact area | region in the back echo area | region in a biological image. FIG. 3 is a cross-sectional configuration diagram of a specific configuration in a measurement unit 30. The process flow figure explaining the tumor determination process which concerns on this embodiment. Explanatory drawing for demonstrating theoretical value calculation means S102. Explanatory drawing for demonstrating theoretical value calculation means S102. Explanatory drawing for demonstrating theoretical value calculation means S102.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image acquisition means 2 Extraction means 3 Irradiation means 4 Detection means 5 Determination means

Claims (6)

Image acquisition means for transmitting and receiving ultrasound to acquire a living body image inside the living body;
Extraction means for extracting a suspicious site based on the biological image;
Irradiation means for irradiating the inside of the living body with a first light having a first wavelength of a light absorption band of a benign tumor and a second light having a second wavelength of a light absorption band of a malignant tumor;
Detecting means for detecting light emitted from the inside of the living body based on the irradiation means;
A tumor detection apparatus comprising: a determination unit that analyzes changes in light intensity of the emitted light at the first and second wavelengths to determine a type of cellular tissue at the site. The tumor detection apparatus according to claim 1, wherein the extraction unit analyzes a contrast difference on the biological image and extracts a low-contrast part as the part. The tumor detection apparatus according to claim 1, wherein the extraction unit extracts the part based on a difference in texture on the biological image. The extraction means analyzes the presence or absence of a boundary line break that occurs in the vicinity of the skin on the living body image and the presence or absence of a high contrast area in a back echo area of the living body image. 2. The tumor detection apparatus according to claim 1, wherein when both are present, a region between the region where the boundary line is broken and the high contrast region is extracted as the region. Image acquisition means for transmitting and receiving ultrasound to acquire a living body image inside the living body;
Irradiation in which the first light having the first wavelength of the light absorption band of the benign tumor and the second light having the second wavelength of the light absorption band of the malignant tumor are irradiated to the inside of the living body where the biological image is acquired. Means,
Detecting means for detecting light emitted from the inside of the living body based on the irradiation means;
Analyzing a light intensity change at the first and second wavelengths of the emitted light, and determining a tissue type of the tissue at the site, and a tissue determination unit,
The cell tissue determination means includes
First analysis means for analyzing the presence or absence of a site suspected of being a tumor based on the biological image;
When the first analysis means determines that the part is present, at least the optical constants of the tissues of the benign tumor and the malignant tumor are applied to the part, and each of the light intensities detected by the detection means A theoretical value calculating means for calculating a theoretical value;
First difference calculating means for calculating a difference between each theoretical value calculated by the theoretical value calculating means and an actual measured value of light intensity at the first and second wavelengths detected by the detecting means;
A first threshold value comparing means for comparing the calculated difference with the threshold value using a range of measurement variations of the light intensity detected by the detecting means that is measured in advance as a threshold value;
When the difference is equal to or less than the threshold value by the first threshold value comparing means, first determining means for determining that either the benign tumor or the malignant tumor satisfying this relationship exists;
And a second determination unit that determines that the part is not the benign tumor or the malignant tumor when the difference is larger than the threshold by the first threshold comparison unit. apparatus. When the first analysis means determines that the region does not exist, the presence / absence of a boundary line generated near the skin on the biological image and the presence / absence of a high-contrast region in the back echo area of the biological image are analyzed. And when there is both a break in the boundary line and the high contrast region, a second analysis means for extracting a region between the boundary line and the high contrast region as a part;
When the second analysis means determines that the part is present, at least the optical constants of the tissues of the benign tumor and the malignant tumor are applied to the part, and each of the light intensities detected by the detection means A theoretical value calculating means for calculating a theoretical value;
Second difference calculating means for calculating a difference between each theoretical value calculated by the theoretical value calculating means and an actual measured value of light intensity at the first and second wavelengths detected by the detecting means;
A second threshold value comparing means for comparing the calculated difference with the threshold value, using a range of measurement variations of the light intensity detected by the detecting means that is measured in advance as a threshold value;
When the difference is less than or equal to the threshold value by the second threshold value comparing means, third determining means for determining that either the benign tumor or the malignant tumor satisfying this relationship exists;
When the difference is larger than the threshold value in the second threshold comparison means, a fourth determination means for determining that the benign tumor or the malignant tumor does not exist in the living body;
When it is determined that there is no site in the second analysis unit, a fifth determination unit that determines that the benign tumor or the malignant tumor does not exist inside the living body;
The tumor detection apparatus according to claim 5, further comprising: