JP7266293B2 - SPECKLE SIGNAL CONDITIONING DEVICE AND METHOD FOR CALIBRATION OF IMAGE MEASUREMENT DEVICE USING THE SAME - Google Patents

Description

The present invention irradiates a biological tissue having blood cells with a laser beam, measures the blood flow velocity based on the speckle signal reflected from the biological tissue, and visualizes it. A speckle signal adjustment device that equates numerical values to the same value as a standard device when a measurement target with a blood flow velocity of Regarding diagnostic methods.

A conventional blood flow velocity measuring device irradiates a biological tissue having blood cells such as the fundus of the eye and skin with a laser beam, and an image of a random speckled pattern formed as a result of interference of reflected light from the blood cells, a so-called speckle image. is guided onto an image sensor such as a solid-state imaging device (CCD or CMOS). A large number of speckle images are continuously captured at predetermined time intervals and stored. A predetermined number of stored images are selected, and a value reflecting the time-varying speed of the output in each pixel of each image is calculated, and the velocity of blood cells (blood flow velocity) is calculated from this value. In this type of blood flow velocity measuring device, the value of the output fluctuation velocity of each pixel corresponds to the movement velocity of the blood cells. It can be displayed in color on a monitor screen as a dimensional image (blood flow map). The actually observed blood flow map is composed of a series of blood flow maps (hereinafter referred to as original maps) calculated at about 30 frames per second, and can be displayed as a moving image. (see Patent Documents 1 to 7).

In addition, the present inventors used the periodicity of heart beats (heartbeats) for a series of original maps obtained by blood flow measurement for several seconds, and converted the original maps from the beginning of each heartbeat to the corresponding original map. The maps are averaged to create an average blood flow map for one heartbeat (hereinafter referred to as a heartbeat map), and the changes in blood flow within one heartbeat are analyzed at each site within the observation field of view to identify sharp arterial By introducing a numerical value, such as skewness, that can distinguish between areas with rising waveforms and areas with venous gently rising and falling waveforms, arterial pulsating areas and venous pulsating areas can be distinguished on the blood flow map. We also proposed a blood flow velocity imaging device that can display (see Patent Document 8).

Furthermore, the present inventors added a new blood flow image diagnosis function to a conventional device, obtained the strength of the fundamental frequency of the time-series blood flow data in a predetermined area in the heartbeat strength calculation unit, and used the external signal strength as a basis. Also proposed is a hemodynamic imaging diagnosis apparatus that visualizes heartbeat intensity, which represents heartbeat intensity (see Patent Document 9).

A blood flow dynamic imaging diagnostic apparatus creates a blood flow map that displays a two-dimensional image of blood flow distribution in living tissue. A blood flow map is obtained by calculating the rate of change in light intensity at each pixel on a plurality of captured images and mapping the rate of change, and reflects the movement of blood cells. Each pixel on the blood flow map has a blood flow value, with a high value for areas where blood cells move fast and a low value for areas where blood cells move slowly.

This blood flow value is a numerical value that reflects the movement of blood cells, but it cannot be calculated as an absolute speed, such as mm/sec. In other words, it is a numerical value that quantifies the rate of change in light intensity, and generally uses what is called contrast, and is said to be difficult to convert into an absolute speed.

This is easy to understand if we consider races with different pigment densities. For example, assume that there are subjects with the same blood flow velocity but different dye concentrations. In this case, although the same blood flow velocity and the same blood flow value are expected, the blood flow values are not actually the same. For example, in the case of a person with a high pigment concentration, the scattered light of the laser is absorbed by the dark pigment in the body, and the contrast of the speckles formed by the rapid attenuation of the scattered light increases. On the other hand, when the dye concentration is low, the laser scattered light is less likely to be absorbed by the dye and the scattered light is less likely to attenuate, leading to a decrease in contrast and an increase in the blood flow value. As a result, even if the blood flow velocity is the same, the blood flow value will be lower due to the contrast difference in people with high pigment density. In order to correct this difference in blood flow values, the present inventors have also proposed a blood flow imaging apparatus that corrects the difference in blood flow values due to pigment concentrations (see Patent Document 7). It is a relative correction of the blood flow value between species, and it was considered difficult to convert the blood flow value to the blood flow velocity as an absolute value.

As mentioned above, blood flow values used in hemodynamic imaging diagnostic equipment are relative values. When measuring the blood flow in a predetermined region, it is expected that the blood flow value output for each machine of the blood flow dynamic imaging diagnostic device is the same value. The inventors have developed a standard machine (hereafter referred to as a standard We have been calibrating each hemodynamic imaging diagnostic device that we manufacture.

This conventional calibration method will be described. First, the subject's blood flow value is measured alternately between the standard machine and the manufactured blood flow dynamic imaging diagnostic device (hereinafter referred to as the product). A plurality of paired blood flow values are obtained by measuring the same area of the subject with the prototype and the product. A scatter diagram is drawn from the blood flow values obtained in pairs with the blood flow value (x) of the standard machine on the horizontal axis and the blood flow value (y) of the product on the vertical axis to obtain a regression line. FIG. 14 shows an example of a scatter diagram in which the blood flow value (y) of the product and the blood flow value (x) of the standard machine are measured and plotted. In order to match the blood flow value of the product with the blood flow value of the standard machine, the slope (= 0.9329) and the intercept (= 0.2366) of Equation 2 of the obtained regression line 1 should be set to slope = 1. The blood flow value of the product is multiplied by the proportionality constant so that the intercept is equal to 0, and the correction constant is added so that the intercept is 0 for linear correction.

With this conventional calibration method, although it is possible to reliably calibrate the hemodynamic imaging diagnostic apparatus that will become a product, there are the following four limitations.
First, a healthy organism, ie a healthy subject, is required. In order to stabilize the blood flow, it is necessary to select subjects with healthy blood flow without diseases such as hypertension and immobilize the subjects. Since the subject is fixed, calibration cannot be performed when the target subject is absent.

Next, there is a time constraint during calibration. Since the object to be measured is a living body, the blood flow changes throughout the day. Due to this diurnal variation, it is necessary to devise measures to measure in a short period of time during calibration in order to always obtain a stable blood flow value. For example, the standard machine and the product are alternately measured repeatedly in a short period of time, and measurements are made while ensuring that the repeatedly measured blood flow values are stable. such as finishing the measurement of In addition, since a scatter diagram is created from the blood flow values of a living body that easily change and a regression line is obtained, the paired blood flow values vary, so a large number of blood flow value samples are required. There is also the problem that it takes time to measure to increase the number of .

Furthermore, the following two points can be given as restrictions on the location.
First of all, it is necessary to install the standard machine and the product side by side in order to perform repeated measurements in a short time. For this reason, space is required for installing these standard machines and products side by side.
Secondly, the standard machine consists of finely adjusted optical parts, and there is a risk that the adjusted optical system will go out of order when the standard machine is transported, so it cannot be easily moved. For this reason, there was also the problem that calibration could not be performed at places other than the factory.

Japanese Patent Publication No. 5-28133 Japanese Patent Publication No. 5-28134 JP-A-4-242628 JP-A-8-112262 Japanese Patent Application Laid-Open No. 2003-164431 Japanese Patent Application Laid-Open No. 2003-180641 International Publication No. 2014/175154 A1 pamphlet WO 2008/69062 A1 pamphlet International Publication No. 2018/003139 A1 pamphlet

To calibrate a hemodynamic imaging diagnostic device, a standard machine and a subject were required, and it could not be performed anytime and anywhere. In particular, it has not been possible to calibrate easily in a limited space such as a hospital where a hemodynamic imaging diagnostic apparatus is installed. From the site, it seems that the blood flow value output from the hemodynamic imaging diagnostic device is not unstable due to failure, etc. There has been a need for a means of confirming whether the device is operating normally and confirming the soundness of blood flow values.

In addition, there is a demand for a calibration device that can easily calibrate blood flow imaging diagnostic equipment for the same model of equipment at any time without restricting the subject for calibration at the manufacturing site.

Furthermore, when examining correction methods for different dye densities, subjects with different dye densities are required, but it is not easy to secure subjects with different dye densities. There is also a demand for a method of calibrating the blood flow value, which depends on the pigment concentration, by taking into account the influence of the pigment concentration.

As described above, the problem to be solved by the present invention is to perform stable calibration and abnormality diagnosis of an imaging diagnostic apparatus without using a living body as a means to replace conventional calibration methods and abnormality diagnosis methods, without time and place restrictions. to be able to do so.

Another object of the present invention is to provide a calibration device capable of correcting blood flow values due to differences in pigment concentration.
As a result, calibration of hemodynamic imaging diagnostic equipment, which until now could only be done at the manufacturing site, can now be performed anywhere, anytime, and the soundness of the blood flow value of the hemodynamic imaging diagnostic equipment can be easily verified. .

The speckle signal adjustment device of the present invention multiple-scatters an incident laser beam, modulates it into a speckle signal, and emits it. a body, a light emitting/receiving angle adjustment unit that adjusts the light receiving angle to the scatterer by refracting the laser light incident on the scatterer, an optical index adjustment unit that adjusts the concentration of the pigment that attenuates the laser light, and a scattering a drive for moving the body at a desired speed.

In this case, a subdivision means may be provided for subdividing the laser beam to be incident on the scatterer to produce a difference in optical path length.
Further, the movement of the scatterer by the drive unit may be rotation.
Further, an attachment means may be provided for detachably attaching to an imaging measurement device for measuring values based on the contrast of the laser speckle image.

Further, the method for calibrating an imaging diagnostic apparatus of the present invention measures a value based on the contrast of a laser speckle image, and uses the above-mentioned speckle signal adjustment apparatus as a standard imaging measurement apparatus. For the calibration target aircraft, the relationship between the moving speed of the scatterer and the value based on the contrast of the laser speckle image is obtained, and the calibration target aircraft is calibrated based on the difference between the two obtained relationships.

Further, the method for diagnosing an abnormality of an imaging measuring device according to the present invention measures a value based on the contrast of a laser speckle image, and uses the speckle signal adjustment device described above to obtain a standard imaging measuring device. and the aircraft to be diagnosed, the relationship between the moving speed of the scatterer and the value based on the contrast of the laser speckle image is obtained, and if the difference between the two obtained relationships exceeds a predetermined value, it is determined to be abnormal. .

In the past, calibration of hemodynamic imaging diagnostic equipment was performed by comparing the images of the living body between the standard machine and the product. Therefore, the place where calibration can be performed was limited to the factory. According to the present invention, since neither a healthy living body nor a standard machine needs to be arranged, there is no place limitation, and calibration can be easily performed anywhere, even at the site other than the factory.

In addition, by using the product of the present invention, it is possible to easily confirm that the blood flow value output by the blood flow imaging diagnostic apparatus is healthy.

Since blood flow values, which are relative values, are calibrated identically for races with different dye densities, it is possible to provide a calibration device that considers dye densities.

1 is a schematic configuration diagram showing an example of an embodiment of a speckle signal adjustment device of the present invention; FIG. FIG. 4 is a diagram illustrating the concept of operation of the speckle signal conditioning apparatus of the present invention; It is a conceptual diagram of a subdivision means. FIG. 2 is a conceptual diagram of the surface of a solid scatterer; It is a figure for demonstrating the mode that a laser beam injects with respect to a solid scatterer, (a) is a figure when a refraction angle is large, (b) is a figure when a refraction angle is small. FIG. 2 is a schematic configuration diagram showing how the speckle signal adjustment device is attached to the hemodynamic imaging diagnostic device; 1 is a flow chart for creating master data, showing an example of an embodiment of a method for calibrating an imaging diagnostic apparatus 3 using a speckle signal adjustment apparatus of the present invention. 1 is a flow chart showing an example of an embodiment of a calibration method for an imaging diagnostic apparatus 3 using the speckle signal adjustment apparatus of the present invention, and obtaining a calibration number of a product (calibration target machine). FIG. 4 shows an example of a scatter diagram describing a regression line before calibrating a product (machine to be calibrated) according to the present invention; FIG. FIG. 10 shows an example of a scatter diagram describing a regression line after calibrating a product (machine to be calibrated) according to the present invention; FIG. FIG. 10 shows an example of a scatter diagram used when detecting an abnormality by the abnormality diagnosis method for the imaging diagnostic apparatus of the present invention; FIG. FIG. 4 is a schematic configuration diagram showing another embodiment of the speckle signal conditioning device of the present invention; FIG. 4 is a schematic configuration diagram showing still another embodiment of the speckle signal conditioning device of the present invention; Here is an example of a scatter diagram used for calibration using a conventional standard machine and product.

The invention will now be described on the basis of examples.
<Speckle signal conditioner>
FIG. 1 shows an example of an embodiment of the speckle signal conditioning device of the present invention. The speckle signal adjustment device 4 is used, for example, for calibration and abnormality diagnosis of the imaging measurement device 3 that measures the value based on the contrast of the laser speckle image.

The imaging measurement device 3 is, for example, a hemodynamic imaging diagnostic device (hereinafter referred to as a hemodynamic imaging diagnostic device 3). However, the present invention is not limited to the hemodynamic imaging diagnostic apparatus 3, and any laser blood flowmeter having a laser light source and a camera capable of observing speckles, for example, can be applied.

In the hemodynamic imaging diagnostic device 3, the degree of modulation of the speckle signal is calculated using light receiving elements arranged one-dimensionally or two-dimensionally, and the contrast is calculated from the image obtained using light receiving elements such as CCDs, It is output as a blood flow value. In practice, when the modulation of the speckle signal imaged on one pixel is low, the speckle signal changes slowly. When this light is received by spatially continuous pixels, an output proportional to the amount of received light is obtained, so that a sharp speckle image is obtained and the contrast of the obtained speckle image is increased. Conversely, if the modulation is high, the image becomes a speckle image with no sharpness due to the integration effect of the light receiving element, and the contrast is lowered. The reciprocal of contrast is the blood flow value, so if the contrast is high, that is, the lower the speckle signal modulation, the lower the blood flow value, and conversely, if the contrast is low, that is, the higher the speckle signal modulation, the blood flow value is get higher Therefore, at the time of calibration, it is very important to control the degree of modulation of the speckle signal, which is the blood flow value, within the speckle signal adjustment device 4 in accordance with the band of the actual blood flow. If possible, it is desirable that the range of blood flow values used for this calibration should have a sufficient range and resolution from below the minimum value to above the maximum value of the range of blood flow to be measured.

In this embodiment, the speckle signal used for calibration and abnormality diagnosis of the hemodynamic imaging diagnostic device 3 that emits a focused laser beam toward the irradiation target, for example, the hemodynamic imaging diagnostic device 3 for the fundus The adjustment device 4 will be explained.

The speckle signal adjustment device 4 multiple-scatters the incident laser beam 5, modulates it into a speckle signal, and emits it. A body 10, a light projection/receiving angle adjustment unit 6 that refracts the laser light 5 incident on the scatterer 10 to adjust the light receiving angle to the scatterer 10, and an optical that adjusts the concentration of the pigment that attenuates the laser light 5. An index adjusting unit 8 and a driving unit 9 for moving the scatterer 10 at a desired speed are provided.

In addition, since the speckle signal adjustment device 4 of the present embodiment performs calibration and abnormality diagnosis of the blood flow dynamic imaging diagnostic device 3 that emits a focused laser beam toward an irradiation target, It has a subdivision means 26 for subdividing the laser beam incident on the scatterer 10 . The subdivision means 26 is provided, for example, in the light projection/reception angle adjusting section 6 . By passing the laser light 5 which is a focused laser light through the segmentation means 26 , it can be converted into diffused light and made incident on the optical index adjustment section 8 .

As will be described later, the speckle used for calibration and abnormality diagnosis of the blood flow dynamic imaging diagnostic device 3 that emits a laser beam that diffuses toward the irradiation target, for example, the blood flow dynamic imaging diagnostic device 3 for skin In the case of the signal conditioner 4, the segmentation means 26 can be omitted.

FIG. 2 shows the concept of operation of the speckle signal conditioner 4 . The speckle signal adjusting device 4 includes a light projecting/receiving angle adjusting section 6 , an optical index adjusting section 8 , and a scatterer 10 on the path of the laser light 5 emitted from the hemodynamic imaging diagnostic device 3 . A subdividing means 26 is provided in the light projection/reception angle adjusting section 6 .

The laser beam 5 emitted from the laser beam irradiation unit (not shown) of the hemodynamic imaging diagnostic device 3 is focused toward the light projection/reception angle adjustment unit 6, and the light projection/reception angle is It passes through the adjusting unit 6 and the optical index adjusting unit 8, reaches the scatterer 10, is reflected by the scatterer 10, passes through the optical index adjusting unit 8 and the light projection/receiving angle adjustment unit 6, returns, and hemodynamics. It is incident on a camera section (not shown) of the imaging diagnostic device 3 .

The hemodynamic imaging diagnostic device 3 irradiates the front surface 6 a of the light projection/reception angle adjustment unit 6 of the speckle signal adjustment device 4 with the laser beam 5 . The light projecting/receiving angle adjusting unit 6 subdivides the traveling direction of the laser beam 5 into at least one or more directions on the front surface 6a, the inside 6b, or the rear surface 6c with respect to the traveling direction of the laser beam 5, and refracts the traveling direction of the laser beam 5. It has a structure (subdividing means 26) for adjusting the direction. In this embodiment, a rough surface is provided as the subdivision means 26 . FIG. 3 shows the concept of the subdivision means 26. As shown in FIG. This adjustment structure is arranged two-dimensionally on a plane perpendicular to the traveling direction of the laser beam 5, adjusts the refraction direction of the traveling laser beam 5, and further refracts the laser beam 5 in the optical index adjustment section 8. to prevent the light receiving angle to the scatterer 10 from becoming excessively large.

The rough surface serving as the subdivision means 26 provided in the light projection/reception angle adjusting section 6 is finely distributed so as to change the optical refractive index slightly obliquely from the plane perpendicular to the traveling direction of the laser light 5. , and are distributed such that the rear surface 6c, which is the light projecting/receiving surface of the laser light 5, is directed in various directions. The subdivision means 26 can subdivide the passing laser light 5 .

Assuming that the traveling laser light 5 is a luminous flux, the laser light 5 output from the light projecting/receiving angle adjusting unit 6 is subdivided by the subdivision means 26 so as to be finely divided into at least one or more luminous fluxes refracted in a plurality of directions. Reassembled into a set of luminous fluxes.

Further, the light projection/receiving angle adjusting section 6 can adjust the pigment concentration to attenuate the passing laser beam 5 to obtain the laser beam 5 with the pigment concentration adjusted. The amount of laser light 5 can be attenuated by increasing the dye density. By attenuating the amount of laser light, it is possible to adjust the number of scattering times of the laser light 5 passing through each section in the subsequent stage and control the degree of modulation of the speckle signal.

Laser light 5 , which is a collection of fine laser beams output from light projection/light reception angle adjustment unit 6 , enters optical index adjustment unit 8 . The optical index adjustment unit 8 adjusts the refraction angle of the laser beam 5 by means of a substance arranged in the optical index adjustment unit 8 so that the refracted laser beam 5 does not spread too much.

The optical index adjustment unit 8 also has a role of adjusting the dye density and attenuating the laser light 5 passing through. The optical index adjustment unit 8 is made up of liquid, for example, and can adjust the dye density by increasing or decreasing the amount of dye in the liquid. When the laser light 5 is attenuated by adjusting the dye density to be high, the number of times of multiple scattering in the scatterer 10 in the latter stage is reduced. Reducing the number of times means that the laser light 5 does not penetrate deep into the scatterer 10 . The speckle of the laser beam 5 is an interference pattern caused by the optical path difference of the scattered light, but the laser scattered light with a shallow depth of penetration and a small number of times of multiple scattering becomes scattered light with high coherence. Time-varying speckle formed from highly coherent scattered light becomes high-contrast speckle in a hemodynamic imaging device and is quantified as a low blood flow value. On the other hand, when the dye concentration is adjusted to be thin, the laser light 5 penetrates deep inside the scatterer 10, the number of times of multiple scattering increases, and scattered light with low coherence is obtained. The time-varying speckle formed from low-coherence scattered light results in low-contrast speckle and high blood flow in contrast to the dye concentration adjusted to high in the hemodynamic imaging device. digitized into a value. By adjusting the dye concentration in this manner, the desired blood flow value can be controlled.

The laser beam 5 whose refraction direction has been further adjusted by the optical index adjustment unit 8 becomes a speckle-like light beam, which is a random speckle pattern, while passing through the optical index adjustment unit 8 and reaches the scatterer 10 .

The scatterer 10 is, for example, a disk-shaped solid scatterer (hereinafter referred to as the solid scatterer 10). The solid scatterer 10 has a structure (for example, a rough surface) that multiple-scatters the laser light 5 on its surface or inside. This structure may be two-dimensionally arranged on the surface of the solid scatterer 10, or three-dimensionally distributed on the surface or inside. As for the structure for multiple scattering, in addition to the multiple scattering by the rough surface, the multiple scattering may be caused by the pigment of the glass inside the solid scatterer 10 . FIG. 4 shows a structure for multiple scattering distributed three-dimensionally on the surface of the solid scatterer 10 .

As the solid scatterer 10, for example, white diffusion glass (Edmund Optics Japan Co., Ltd.) can be used.

The drive unit 9 includes, for example, an electric motor 30 that moves the solid scatterers 10 and a sensor 31 that detects the moving speed of the solid scatterers 10 (FIG. 1). In this embodiment, the movement of the solid scatterers 10 is rotation, and the sensor 31 is a rotary encoder that detects the moving speed of the solid scatterers 10 .

The drive unit 9 is controlled by a scatterer control unit 11 . The scatterer control unit 11 is configured, for example, by installing and executing a control program in a computer. The scatterer control unit 11 can recognize the rotation speed of the solid scatterer 10 from the signal from the sensor 31 and can control the electric motor 30 to rotate the solid scatterer 10 at an arbitrary speed.

That is, the scatterer control section 11 has a mechanism for moving the solid scatterer 10 at an arbitrary speed, and can move the solid scatterer 10 at an arbitrary speed according to a command. When the solid scatterer 10 is moved from a low speed to a high speed, the number of multiple scatterings increases in each fine beam of the laser light 5 inside the solid scatterer 10 in response to the moving speed. A fine light beam multiple-scattered by the structure inside or on the surface of the moving solid scatterer 10 becomes a laser beam 5 whose vibration direction changes moment by moment as the moving solid scatterer 10 moves. By intentionally changing the speed, the laser light 5 emitted from the solid scatterer 10 has a vibration direction and intensity corresponding to the moving speed of the solid scatterer 10. The change in the luminous flux of the laser light 5 is As a result, it responds to the modulation of the speckle signal formed on the light-receiving element in the hemodynamic imaging diagnostic device 3 . For example, when the solid scatterer 10 moves at a low speed, the number of times of multiple scattering decreases and the modulation of the speckle signal decreases. Conversely, when moving at high speed, the number of times of multiple scattering increases and the modulation of the speckle signal increases.

Although it has been described that the refraction angle is adjusted by the optical index adjuster 8, since the characteristics of the solid scatterer 10 have been described, this adjustment point will be explained. If the refraction angle at the optical index adjustment unit 8 is too large, the laser light 5 reaching the solid scatterer 10 is diffused and enters the solid scatterer 10 at a wide acceptance angle (FIG. 5(a)). . When incident at a wide acceptance angle, a fine beam of the laser beam 5 is consequently scattered widely within the solid scattering medium 10, the number of multiple scattering increases for each beam, and the modulation of the speckle signal becomes higher. If the modulation of the speckle signal becomes higher, the modulated signal tends to saturate beyond the detection capability of the hemodynamic imaging apparatus 3, and the blood flow value becomes saturated, making correct calibration difficult. Therefore, as shown in FIG. 5(b), the refraction angle of the optical index adjuster 8 should not be too large. The role of adjusting the angle of refraction in the optical index adjuster 8, which adjusts the degree of multiple scattering within the solid scatterer 10 so that the blood flow value does not saturate, is very important.

The laser beam 5 output from the solid scatterer 10 is a set of at least one or more beams whose speckle signals are modulated by appropriately adjusted multiple scattering as described above. In addition, the solid scattering medium 10 can have a rough structure with a change in pigment concentration and a function of appropriately attenuating the laser light 5 . For example, the attenuation of the laser beam 5 can be increased by increasing the concentration of the pigment that colors the solid scattering medium 10, and conversely, the attenuation of the laser beam 5 can be reduced by decreasing the concentration of the pigment. . Also, the attenuation of the laser light 5 may be adjusted by changing the color of the pigment that colors the solid scattering medium 10 . For example, the attenuation of the laser beam 5 can be increased by making the color of the pigment darker, and conversely, the attenuation of the laser beam 5 can be reduced by making the color of the pigment lighter. Due to these functions, the laser light 5 can simulate scattered light fluxes caused by people with different pigment densities.

The laser beam 5 output from the solid scatterer 10 passes through the optical index adjustment section 8 again and is input to the light projection/reception angle adjustment section 6 .

The laser beam 5 that has passed through the optical index adjustment unit 8 is a set of one or more fine beams. The light projecting/receiving angle adjusting unit 6 has a structure (segmentation means 26) that adjusts the traveling direction of the laser beam by refracting it in at least one direction. Each of the 1 or more fine beams is decomposed or aggregated. Basically, the fine structure having the light receiving angle in the light projection/light receiving angle adjusting section 6 acts to concentrate a plurality of fine light beams. If a partial beam spans multiple fine structures, it will separate and aggregate with another fine beam. Since a plurality of fine beams are aggregated, the modulation information of the speckle signal contained in each beam is superimposed, and the laser beam 5 output from the front surface 6a of the light projecting/receiving angle adjusting unit 6 is further modulated. adjusted to

The laser light 5 output from the light projection/receiving angle adjusting unit 6 is a set of a plurality of fine beams having modulation information of speckle signals to which speed information of the moving solid scatterer 10 is added. When the laser beam 5 is incident on the hemodynamic imaging diagnostic device 3 , it forms an image as speckles on the light-receiving element in the hemodynamic imaging diagnostic device 3 . In the hemodynamic imaging diagnostic device 3, a blood flow value is calculated for each light receiving element distributed one-dimensionally or two-dimensionally, a blood flow map is created, and the blood flow value of an arbitrary designated region on the blood flow map is calculated. can be output.

Conventionally, a healthy living body has been used as a subject for calibration and abnormality diagnosis. This makes it possible to control the degree of multiple scattering of the stably moving solid scatterer 10 in accordance with the target blood flow value measurement range. It is necessary to acquire a wide range of blood flow values for calibration and abnormality diagnosis. By varying the moving speed of the solid scatterer 10, it is possible to obtain the desired blood flow value.

As shown in FIG. 6, the speckle signal adjustment device 4 of the present embodiment includes attachment means 42 detachably attached to the hemodynamic imaging diagnostic device 3. For example, the hemodynamic imaging diagnostic device 3 It is detachably attached to the blood flow dynamic imaging diagnostic apparatus 3 using a table on which a person's chin is placed when measuring the human eye using .

The speckle signal conditioning device 4 is supported by a support 39 . In addition, the table on which the jaw of the blood flow dynamic imaging diagnostic apparatus 3 is placed has columns 38 supporting it from the left and right. The support 39 of the speckle signal conditioning device 4 is detachably attached to the post 38 by attachment means 42 such as screwing means.

Since the speckle signal adjustment device 4 can be easily attached/detached to/from the blood flow dynamic imaging diagnostic device 3 by the mounting means 42, calibration and abnormality diagnosis of the blood flow dynamic imaging diagnostic device 3 installed on site can be easily performed. be able to.

<Method for calibrating imaging measurement device 3 using speckle signal adjustment device>
Next, a method for calibrating the imaging measurement device 3 using the speckle signal adjustment device 4 will be described. This calibration method is a method for calibrating the imaging measurement device 3 that measures a value based on the contrast of the laser speckle image, and uses the speckle signal adjustment device 4 to calibrate the standard machine of the imaging measurement device 3 and the calibration target. For each machine, the relationship between the moving speed of the solid scatterer 10 and the value based on the contrast of the laser speckle image is obtained, and the machine to be calibrated is calibrated based on the difference between the two obtained relationships. Blood flow values (measured values) obtained by this method are stable and reproducible because the solid scatterer 10 is used. Therefore, the acquisition of data used for calibration can be done independently without the need to continuously measure the data of the standard machine and the machine to be adjusted as in the conventional method. In addition, once the master data is acquired, the master data can be used for the imaging diagnostic equipment 3 at each site. calibration work can be simplified.

First, the creation of calibration data in the standard machine will be explained. In step 15 of FIG. 7, the scatterer control unit 11 is driven to obtain a blood flow value within the calibration range of the blood flow value using the standard machine of the blood flow dynamic imaging diagnostic device 3 and the speckle signal adjustment device 4. The unit 9 is controlled to move the solid scatterer 10 at at least one or more velocities, and blood flow values (measurement values) corresponding to the velocities are acquired.

In step 16, based on the blood flow values within a wide range for the moving speed obtained with the standard machine using the speckle signal adjustment device 4, the moving speed and the blood flow value paired with the reference at the time of calibration were recorded. Create master data. The master data may be created using blood flow values that are measured at least once in step 15 and created using a statistical method such as averaging or an interpolation method.
Steps 15 and 16 are performed in advance, for example, in a production factory.

Next, acquisition of calibration data in the adjustment target machine of the hemodynamic imaging diagnostic apparatus 3 will be described. Calibration data is acquired in step 17 of FIG. The acquisition method may be the same as the method performed for the standard machine in step 15, or may be a simplified method in which the number of measurements is reduced by changing the moving speed.

In step 18, on the basis of blood flow values paired with at least one moving speed measured in step 17, adjustment target machine data storing blood flow values paired with moving speeds is created. For the relationship between the moving speed and the blood flow value paired, a method such as polynomial modeling may be used to estimate the blood flow value from the moving speed.

In step 19, a scatter diagram used for calibration is created from the master data created in step 16 and the adjustment object machine data created in step 18. FIG. In creating the scatter diagram, based on the movement speed corresponding to the blood flow value measured by the machine to be adjusted, the blood flow value corresponding to the movement speed in the master data is extracted. Plot using at least one or more paired data consisting of blood flow values measured in .

In step 20, based on the scatter diagram created in step 19, correction is performed based on the blood flow value characteristics of the machine to be adjusted with respect to the standard machine. The correction method is a method of obtaining the calibration normal number for correcting the blood flow value of the adjustment target machine based on the equation of the regression line, or a method of taking the same value as the standard machine for the blood flow value of the adjustment target machine. You can create a table, etc.

As an example of the calibration method, a regression line 21 before calibrating the machine to be adjusted and an equation 22 of the regression line are illustrated in FIG. 9 and explained. For example, this regression line 21 and its formula 22 are the relationship between the moving speed of the solid scatterer 10 and the value based on the contrast of the laser speckle image. The scatter diagram in FIG. 9 refers to the movement speed when the blood flow value of the machine to be adjusted is measured, and based on this movement speed, the blood flow value x of the standard machine is extracted from the master data. The blood flow value y of the machine to be calibrated is plotted. Let Slope_pre be the slope of the regression line of the adjustment target machine before correction, and Intercept_pre be the intercept. In the example of FIG. 9, Slopr_pre=0.8 and Intercept_pre=1.54. In order to match the blood flow value of the machine to be adjusted with the blood flow value of the standard machine, a conversion formula applied to the blood flow value of the machine to be adjusted so that the slope of the regression line is 1 and the intercept is 0 should be created.

Let x be the blood flow value before correction of the machine to be adjusted, and let y_post be the blood flow value after correction.

By inputting Slope_pre and Intercept_pre as parameters for correction to the machine to be adjusted, the machine to be adjusted corrects the measured blood flow value x to y_post and outputs it as a blood flow value.

Based on the example in FIG. 9, a scatter diagram was created based on the blood flow value (y_post) of the adjustment target machine corrected using the conversion formula of Equation 1 and the blood flow value x of the standard machine extracted from the master data. An example is shown in FIG. A regression line formula 24 is a formula for the corrected regression line 23 . Since the slope of the regression line equation 24 with respect to the blood flow value x of the standard machine is 1, and the intercept is also 0, the corrected blood flow value of the adjustment target machine matches the blood flow value of the standard machine. It can be seen that This calibration method also made it possible to match the blood flow values of the machine to be adjusted with the blood flow values of the standard machine.
Note that steps 17 to 20 are performed, for example, at the site where the machine to be adjusted is installed.

An example of the calibration method using the speckle signal adjustment device 4 has been described above. Basically, if we can compare the blood flow values with respect to the movement speed of the master data and the data of the machine to be adjusted, we can create a scatter diagram of the blood flow values of the standard machine and the machine to be adjusted. Calibration of the flow imaging diagnostic device 3 becomes possible. This eliminates the need for a standard machine for calibration, which has been necessary in the past, and enables calibration without a standard machine as long as there is master data.

In addition, by realizing the speckle signal adjustment device 4 with good reproducibility, when the measured blood flow value has a deviation of more than the uncertainty, the measured blood flow dynamic imaging diagnostic device 3 is suspected, and it has also become possible to detect an abnormality in the hemodynamic imaging diagnostic device 3 .

When performing calibration with a different pigment concentration, the data of the light projection/receiving angle adjustment unit 6, the optical index adjustment unit 8, or the solid scatterer 10 adjusted to the pigment concentration that matches the target race is used for hemodynamics. The blood flow value can be corrected by measuring with the imaging diagnostic device 3 and comparing it with the master data before the dye density is changed.

In order to present an effective embodiment according to the present invention, FIG. 1 shows an example of the configuration of the speckle signal adjustment device 4 of the hemodynamic imaging diagnostic device 3. As shown in FIG. FIG. 1 is a schematic view of the speckle signal conditioning device 4 viewed from the side.

A laser beam 5 is emitted from the hemodynamic imaging diagnostic device 3 . Since the light projecting/receiving angle adjuster 6 allows the laser light 5 to pass therethrough, it is desirable that the material is made of a transparent substance having a refractive index of 1.3 to 1.8. For example, optical glass or easily processed optical plastic may be used. Any material that adequately transmits the laser light 5 or has the property of attenuating the laser light 5 with a dye may be a candidate. The light projecting/receiving angle adjusting portion 6 may have any shape as long as it does not hinder the progress of the laser light 5 . Here, as an example of the material of the light projecting/receiving angle adjusting portion 6, glass, which is easily available, is used, and a cylindrical glass rod is used.

The projection/receiving angle adjusting portion 6 is provided with a rough surface as a subdivision means 26 . In this embodiment, the subdivision means 26 is provided on the rear surface 6c of the light projection/reception angle adjusting section 6. As shown in FIG. However, instead of the back surface 6c, or in addition to the back surface 6c, the front surface 6a may be provided with a rough surface as the subdivision means 26. FIG. As means for providing rough surfaces on the rear surface 6c and the front surface 6a, it is conceivable to use polishing means such as an abrasive. Alternatively, the subdivision means 26 may be provided inside the light projection/reception angle adjusting section 6 . In other words, the subdivision means 26 may be constructed by laminating materials having different refractive indexes in the light projection/reception angle adjusting section 6 with three-dimensional variations. As a method of providing three-dimensional variation by using substances with different refractive indices, a fine structure (rough surface) is once created on the back surface of the glass rod that will be the light emitting/receiving angle adjusting portion 6, and glass is placed on it. A material with a different refractive index (for example, an adhesive such as epoxy resin) is laminated with glass rods, and the laminated surface is further provided with a fine structure (rough surface) or a flat layer to vary the refractive index. You can also have The number of layers to be laminated is not limited to one and may be plural.

The optical index adjuster 8 is liquid stored in the bath 28 . As a material for the optical index adjusting portion 8, a liquid whose refractive index can be easily adjusted is suitable. For example, it is filled with water, which is a liquid with a refractive index of 1.33. That is, when glass is used as the material of the light projection/receiving angle adjusting section 6, a liquid such as water having a refractive index of about 1.3 and free of scattering particles is suitable as the material of the optical index adjusting section 8. is not limited to

Since the bath 28 uses a liquid for the optical index adjusting section 8, it has a structure for stably storing the liquid. In the case of this example, the glass rod serving as the light projection/light reception angle adjusting portion 6 is arranged to plug the bathtub 28 so that the liquid does not leak.

Solid scatterer 10 is a glass diffusion plate. The surface 10a of the solid scatterer 10 is polished with an abrasive, and the coarse structure of the polished surface 10a and the fine glass structure in the glass diffusion plate function as the moving solid scatterer 10 to promote multiple scattering. Although a glass diffusion plate is shown here as an example, opal glass or the like having fine air bubbles inside may also be used.

The solid scatterer 10 is arranged to rotate by rotating a motor shaft 32 by a motor 30, and rotates in the liquid as the optical index adjustment unit 8. FIG. Motor 30 gives a voltage from the outside to give rotational motion to motor shaft 32 .

A sensor 31 such as a rotary encoder detects the rotation of the motor shaft 32 and detects the number of revolutions per second of the solid scattering medium 10 . Based on the detected rotational speed, the moving speed of the solid scatterer 10 is calculated and used as the moving speed of the solid scatterer 10 at the time of calibration.

The speckle signal adjustment device 4 is installed in front of the hemodynamic imaging diagnostic device 3 when calibrating the hemodynamic imaging diagnostic device 3 or when diagnosing an abnormality. It is highly portable because it does not take up much space. The speckle signal adjustment device 4 of the present invention can perform calibration and abnormality diagnosis, which could only be performed at the time of shipping, even at a site such as a hospital, thereby solving the problem.

<Method for Diagnosing Abnormality of Imaging Measuring Device 3 Using Speckle Signal Adjusting Device>
As an effective embodiment of the present invention, means (abnormality diagnosis method) for confirming whether the hemodynamic imaging diagnostic apparatus 3 is operating normally and whether the blood flow values are sound will be described.

Until now, the hemodynamic imaging diagnostic apparatus 3 has no means for confirming whether blood flow values are correctly output within the range of blood flow that can be output. Even if the subject's blood flow is measured and the blood flow value is obtained, it is not a numerical value near the maximum value within the range of blood flow values that can be output by the blood flow imaging diagnostic device 3, so the blood flow image can be reliably obtained. It was necessary to confirm that a blood flow value corresponding to a constant and stable speed was obtained within the blood flow value range of the diagnostic apparatus 3 . By using the speckle signal adjustment device 4 of the present invention, it is possible to determine whether a blood flow value corresponding to the velocity is steadily obtained within the range of blood flow values that can be output by the hemodynamic imaging diagnostic device 3. can be secured.

The abnormality diagnosis method of the imaging diagnostic device 3 using the speckle signal adjustment device 4 is based on the moving speed of the solid scatterer 10 and the contrast of the laser speckle image for the standard machine and the diagnostic target machine of the imaging measurement device 3. A value (for example, a blood flow value) is obtained, and if the difference between the two obtained relationships exceeds a predetermined value, it is judged to be abnormal.

That is, the abnormality diagnosis method first uses the hemodynamic imaging diagnostic device 3 to be verified and the speckle signal adjustment device 4 to perform blood flow while changing the velocity of the solid scatterer 10 in the same manner as in the case of calibrating the diagnostic target machine. Measure the flow value.

Next, based on the measured blood flow value y, a scatter diagram (relationship between the moving speed of the solid scatterer 10 and the value (blood flow value y) based on the contrast of the laser speckle image) is used in the same way as when calibrating the diagnostic target machine. ) to check whether the measured blood flow value falls within the predetermined normal range.

FIG. 11 shows an example of a scatter diagram assuming an abnormal occurrence in the measured blood flow values. In the scatter diagram of FIG. 11, a boundary line 33 of the lower limit value of the normal blood flow value corresponding to the velocity with consideration of the uncertainty of the diagnostic target aircraft and a boundary line 34 of the upper limit value are plotted as well. The range in which the blood flow value of the machine to be diagnosed is normal is the region between the boundary line 34 of the upper limit value and the boundary line 33 of the lower limit value. These boundaries are examples of normal ranges and do not necessarily have to be straight lines.

The method for determining the upper and lower limits is as follows. That is, using a hemodynamic imaging diagnostic device that is considered to be normal, paired data of the moving speed of the solid scatterer 10 and the blood flow value (measurement value) (the moving speed of the solid scatterer 10 and the contrast of the laser speckle image value (relationship with blood flow value) based on The data of the velocity and blood flow value pairs obtained are also obtained as master data in the same way for the standard machine, and even if the velocity is the same, the blood flow values exist with some fluctuation. From these fluctuations in velocity and blood flow value, a prediction interval of normal blood flow dynamic imaging diagnostic apparatus 3 with respect to the blood flow value of the standard machine can be obtained by a statistical method. The upper boundary of the prediction interval of this normal hemodynamic imaging diagnostic apparatus can be set as the upper limit, and the lower boundary can be set as the lower limit.

The measurement points are plotted with black dots in FIG. 11 so as to correspond to the blood flow values of the standard machine extracted from the master data. Among the plotted measurement points, the circled measurement points in region 35 are plotted below the boundary line 33 of the lower limit value, and are found to be outside the normal range.
Any deviation from the normal range of the measurement points enclosed by the area 35 is suspected to be a failure of the machine to be diagnosed, requiring maintenance.

As in the example of FIG. 11, it is conceivable that the blood flow value deviates from the normal range only within a certain range. The significance is great not only for manufacturers but also for users.

Although only a few embodiments have been described in detail in this disclosure by way of example only, many such embodiments may be incorporated without substantially departing from the novel teachings and advantages of the present invention. Variations are possible.

For example, the speckle signal adjustment device 4 described above performs calibration and abnormality diagnosis of the hemodynamic imaging diagnostic device 3 that emits laser light condensed toward the irradiation target. However, it is not necessarily limited to this. For example, a speckle signal adjustment device 4 used for calibration and abnormality diagnosis of a hemodynamic imaging diagnostic device (for example, a hemodynamic imaging diagnostic device for skin) 3 that emits a laser beam that diffuses toward an irradiation target. , the subdivision means 26 can be omitted.

The configuration is shown in FIG. This speckle signal adjustment device 4 omits the projection/reception angle adjustment section 6 , and the diffused laser beam 5 is irradiated toward the solid scattering medium 10 . The lower part of the solid scatterer 10 is immersed in a liquid (for example, water) which is the optical index adjusting section 8 . Since the solid scatterer 10 is rotated by the drive unit 9, a liquid film 12 is formed on the surface of the solid scatterer 10 as indicated by the phantom lines in FIG. This liquid film 12 functions as the optical index adjuster 8 . Therefore, the laser beam 5 emitted from the hemodynamic imaging diagnostic device 3 is adjusted in the angle of refraction by the optical index adjustment unit 8 to adjust the angle of acceptance to the solid scatterer 10, and in the liquid that forms the membrane 12. is attenuated by the pigment contained in the solid scatterer 10 .

This speckle signal adjustment device 4, like the speckle signal adjustment device 4 of FIG. 1, multiple-scatters the laser light 5 emitted from the hemodynamic imaging diagnostic device 3, modulates it into a speckle signal, and outputs it. be able to.

Also, in the above description (FIG. 6), the speckle signal conditioning device 4 was attached to the pillar 38 by the attachment means 42, but the location of attachment is not limited to the pillar 38. FIG. For example, as shown in FIG. 13, the speckle signal adjustment device 4 may be directly attached to the lens barrel 40 of the hemodynamic imaging diagnostic device 3 . For example, the speckle signal adjustment device 4 may be detachably attached by fixing the attachment means 42 to the support 39 of the speckle signal adjustment device 4 and fitting the attachment means 42 into the lens barrel 40 . . The mounting means 42 is a plate-like member, and is provided with a hole into which the lens barrel 40 is fitted. Since the speckle signal adjustment device 4 can be attached only by fitting the lens barrel 40 into the hole of the attachment means 42, the speckle signal adjustment device 4 can be easily installed at the site where the hemodynamic imaging diagnostic device 3 is installed. can be attached or removed.

The speckle signal adjustment device of the present invention is used for calibration and abnormality diagnosis of an imaging measurement device 3 that irradiates an object with laser light and images the reflected speckle signal, such as a hemodynamic imaging diagnostic device. can.

3 Blood flow dynamic imaging diagnostic device (imaging measurement device)
4 speckle signal adjustment device 5 laser light 6 light projection/reception angle adjustment unit 8 optical index adjustment unit 9 drive unit 10 solid scatterer 11 scatterer control unit

Claims (6)

A speckle signal adjustment device that multiple-scatters incident laser light, modulates it into a speckle signal, and emits the speckle signal,
a scatterer that multiple-scatters the laser light and reflects it while modulating it into a speckle signal;
a light projecting/receiving angle adjusting unit that adjusts a light receiving angle to the scatterer by refracting the laser beam to be incident on the scatterer;
an optical index adjustment unit that adjusts the concentration of the pigment that attenuates the laser light;
a driving unit for moving the scatterer at a desired speed;
A speckle signal conditioner comprising: 2. The speckle signal adjustment device according to claim 1, further comprising a segmentation means for segmenting the laser beam incident on said scatterer to produce a difference in optical path length. 2. The speckle signal adjustment device according to claim 1, wherein the movement of the scatterer by the drive unit is rotation. 2. The speckle signal conditioning device of claim 1, further comprising mounting means for removably attaching to an imaging measurement device for measuring contrast-based values of laser speckle images. A method for calibrating an imaging measurement device that measures a value based on the contrast of a laser speckle image, comprising:
Using the speckle signal adjustment device according to any one of claims 1 to 4, for the standard machine and the calibration target machine of the imaging measurement device, based on the moving speed of the scatterer and the contrast of the laser speckle image A method of calibrating an imaging measurement apparatus, comprising: obtaining relationships between values and values, and calibrating the calibration target machine based on a difference between the two obtained relationships. A method for diagnosing abnormalities in an imaging measurement device for measuring a value based on the contrast of a laser speckle image,
Using the speckle signal conditioning device according to any one of claims 1 to 4, for the standard machine and the diagnostic target machine of the imaging measurement device, based on the moving speed of the scatterer and the contrast of the laser speckle image A method of diagnosing an abnormality of an imaging measuring apparatus, comprising: determining a relationship with a value, and determining an abnormality when a difference between the two determined relationships exceeds a predetermined value.

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