WO2021145375A1

WO2021145375A1 - Device and method for measuring blood lipid level

Info

Publication number: WO2021145375A1
Application number: PCT/JP2021/001038
Authority: WO
Inventors: 祐次加藤; 一也飯永; 淳高見澤
Original assignee: メディカルフォトニクス株式会社
Priority date: 2020-01-17
Filing date: 2021-01-14
Publication date: 2021-07-22
Also published as: JPWO2021145375A1

Abstract

[Problem] To provide a device and a method by which blood lipid level can be stably measured. [Solution] A device for measuring blood lipid level that comprises: an irradiation unit that irradiates a specific position of a target with light of a first wavelength and with light of a second wavelength, said second wavelength leading to higher absorption by hemoglobin than the first wavelength; a light intensity detection unit that is placed either at a position apart a preset distance from the light irradiation position of the irradiation unit or at a continuous position and detects the intensity of light emitted from the target at multiple positions; and a control unit that calculates the blood vessel depth and the blood vessel size on the basis of the intensity of the light of the second wavelength, calculates the variation in a first effective attenuation coefficient on the basis of the intensity of the light of the first wavelength, and then calculates the lipid level on the basis of the variation in the first effective attenuation coefficient, the blood vessel depth and the blood vessel size.

Description

Blood lipid concentration measuring device and its method

The present invention relates to a blood lipid concentration measuring device and a method thereof.

Postprandial hyperlipidemia has been attracting attention in recent years as a cause of arterial disease, and a method that does not require blood sampling for its diagnosis is desired. Since the change in blood lipid concentration optically corresponds to the change in the scattering coefficient of blood, percutaneous non-invasive measurement by an optical method can be expected (see, for example, Patent Document 1).

According to the method of Patent Document 1, blood sampling can be eliminated by non-invasive lipid measurement. This makes it possible to measure blood lipids not only at medical institutions but also at home. By enabling immediate data acquisition, it becomes possible to measure blood lipids continuously over time.

International Publication No. 2014/087825

The conventional non-invasive lipid measurement method was based on the premise that the measurement target was a uniform scattering medium. However, the living body includes blood vessels and general tissues, and cannot be said to be a uniform scattering medium, and the measured values may fluctuate depending on the measurement position and individual differences. For stable measurement, it is necessary to consider the size and depth of blood vessels (veins) in the living body.

The present invention has been made to solve such a conventional problem, and by providing a blood lipid concentration measuring device and a method capable of stabilizing the measurement of non-invasive blood components. be.

The blood lipid concentration measuring device of the present invention irradiates an irradiation unit that irradiates a predetermined position of a subject with light having a first wavelength and light having a second wavelength that is absorbed by hemoglobin more than the first wavelength. A light intensity detection unit that detects the light intensity at a plurality of positions emitted from the subject at a predetermined interval from the light irradiation position by the unit or at a continuous position, and a light intensity of the second wavelength. The blood vessel depth and blood vessel thickness are calculated from, the amount of change in the first effective attenuation coefficient is calculated from the light intensity of the first wavelength, and the amount of change in the first effective attenuation coefficient is calculated from the blood vessel depth and blood vessel thickness. It has a control unit for calculating the lipid concentration.

In the blood lipid concentration measuring method of the present invention, light of the first wavelength and light of the second wavelength, which is absorbed by hemoglobin more than the first wavelength, are irradiated to a predetermined position of the subject, and the irradiation position of the light is applied. The light intensity at multiple positions emitted from the subject is detected at predetermined intervals or at continuous positions, and the blood vessel depth and blood vessel thickness are calculated from the light intensity of the second wavelength. The amount of change in the first effective attenuation coefficient is calculated from the light intensity of the first wavelength, and the lipid concentration is calculated from the amount of change in the first effective attenuation coefficient, the blood vessel depth, and the blood vessel thickness.

According to the blood lipid concentration measuring device and method of the present invention, it is possible to stabilize the measurement of non-invasive blood components.

It is a figure which shows the structure of the blood lipid concentration measuring apparatus of an embodiment. It is a block diagram which shows the structure of a control system. It is a figure which shows the scattering of light by a blood lipid. Estimated map of vein depth and diameter at a wavelength of 600 nm. A group of calibration curves for blood lipid concentration at a wavelength of 810 nm. It is a flowchart of the lipid concentration measurement process of an embodiment.

Hereinafter, the blood lipid concentration measuring device and the method thereof, which are the embodiments, will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the blood lipid concentration measuring device of the embodiment. FIG. 2 is a block diagram showing a configuration of a control system of the blood lipid concentration measuring device of the embodiment.

As shown in FIG. 1, the blood lipid concentration measuring device 1 of the embodiment includes an irradiation unit 2, a light intensity detection unit 3, and a control unit 4.

The irradiation unit 2 has a light source 22 for irradiating a predetermined irradiation position 21 with light from outside the living body to the inside of the living body at a predetermined part of the living body. The light source 22 can adjust the wavelength of the emitted light by the control unit 4. The irradiation intensity of the light source 22 can be adjusted by the control unit 4.

In the irradiation unit 2 of the embodiment, the length of time for irradiating light such as continuous irradiation of light or pulsed irradiation of light is arbitrary according to the calculation method of the effective attenuation coefficient μeff by the control unit 4 described later. Can be adjusted to.

The irradiation unit 2 may use a light source 22 having a fixed wavelength. The irradiation unit 2 may be a mixture of a plurality of light sources having different wavelengths or light having a plurality of wavelengths. The irradiation unit 2 is, for example, a fluorescent lamp, an LED, a laser, an incandescent lamp, a HID, a halogen lamp, or the like. The illuminance of the irradiation unit 2 is controlled by the control unit 4. In the embodiment, the light source 22 is an LED (Light Emitting Diode).

The light source 22 of the embodiment irradiates different first wavelength light and second wavelength light. The light of the first wavelength is a wavelength at which absorption by hemoglobin is small, and is light for measuring the lipid concentration in blood. The light of the second wavelength is a wavelength that is largely absorbed by hemoglobin, and is light for measuring the depth and diameter of veins.

The first wavelength light is preferably a wavelength that is less absorbed by hemoglobin, and is preferably light in the wavelength range of 800 nm ± 50 nm (that is, 750 nm or more and 850 nm or less).

The light of the second wavelength is preferably a wavelength at which absorption by hemoglobin is strong, and is preferably light of 500 nm or more and 600 nm or less.

The light intensity detection unit 3 receives the light emitted from the living body to the outside of the living body and detects the light intensity. When a plurality of light intensity detecting units 3 (31, 32) are used, the light intensity detecting units 3 (31, 32) are installed at different distances from the irradiation position 21. As shown in FIG. 1, in the embodiment, the first light intensity detecting unit 31 and the second light intensity detecting unit 32 are arranged in order on the same surface and linearly from the irradiation position 21 at predetermined intervals. The light intensity detection unit 3 may be a photodiode, a CCD, or a CMOS.

The light received by the light intensity detection unit 3 is converted into a photocurrent, and this photocurrent is processed by the CPU 41.

As shown in FIG. 1, in the embodiment, the distance from the irradiation position 21 to the first detection position 331 by the first light intensity detection unit 31 is set to the first distance ρ _1, and the distance from the irradiation position 21 to the second light intensity detection unit 32 is set. Let the distance to the second detection position 332 according to be the second distance ρ ₂ .

_{The first distance ρ 1} between the first detection position 331 by the first light intensity detection unit 31 and the irradiation position 21 of the irradiation unit 2 is preferably 3 to 8 mm. When the entry / exit distance is as short as 3 to 8 mm, measurement results in which the characteristics of venous blood dominate can be obtained. _{The second distance ρ 2} between the second detection position 332 by the second light intensity detection unit 32 and the irradiation position 21 of the irradiation unit 2 is preferably 10 to 15 mm. When the entry / exit distance is as long as 10 to 15 mm, measurement results can be obtained in which the surrounding tissue outside the vein is dominant.

As shown in FIG. 3, a predetermined distance ρ is provided between the irradiation position 21 for irradiating the living body with light and the detection position 33 for detecting the light intensity emitted from the blood (E in the figure) in the living body. .. By providing a predetermined distance ρ, the effect of the irradiated light (A in the figure) reflected by the scattering body on the surface of the living body and the scattering body near the surface and directly emitted from the living body (B in the figure) is suppressed. do. After the irradiated light reaches the depth at which blood exists, the light is reflected by the lipid in the blood (D in the figure).

The arrangement when a plurality of

detection positions

331, 332, etc. are provided is not limited to a linear shape as long as they are arranged at different distances from the irradiation position 21, but may be circular, wavy, zigzag, or the like. It can be selected as appropriate. _{Further, the intervals between the first distance ρ 1} and the second distance ρ ₂ from the irradiation position 21 to the

detection positions

331, 332, etc., and the

detection positions

331 and 332 are not limited to a fixed interval, and may be continuous. good.

Next, the configuration of the control system of the blood vessel detection device 1 will be described. FIG. 2 is a block diagram of the blood vessel detection device 1 of the embodiment. CPU (Central Processing Unit) 41, ROM (Read Only Memory) 43, RAM (Random Access Memory) 44, storage unit 47, external I / F (Interface) 48, irradiation unit 2, and The light intensity detection unit 3 is connected. The control unit (controller) 4 is composed of the CPU 41, the ROM 43, and the RAM 44.

The ROM 43 stores in advance the programs and thresholds executed by the CPU 41.

The RAM 44 has various memory areas such as an area for developing a program executed by the CPU 41 and a work area for data processing by the program. The RAM 44 has a storage area for storing calibration data (first calibration data) of the vein depth / diameter estimation map shown in FIG. 4, which will be described later. The RAM 44 has a storage area for storing calibration data (second calibration data) of the blood lipid concentration calibration curve group shown in FIG. 5, which will be described later.

The storage unit 47 stores data such as the detected / calculated light intensity and μ _eff. The storage unit 47 may be an internal memory such as an HDD (Hard Disk Drive), a flash memory, or an SSD (Solid State Drive) that stores non-volatilely. The storage unit 47 may store the first calibration data and the second calibration data, which will be described later.

The external I / F48 is an interface for communicating with an external device such as a client terminal (PC). The external I / F48 may be an interface for data communication with an external device, for example, a device (USB memory or the like) locally connected to the external device, or a network for communication via a network. It may be an interface.

The control unit 4 calculates the blood vessel depth and diameter information (blood vessel thickness) from the light intensity of the second wavelength based on the light intensity detected by the light detection intensity unit 3 (31, 32), and the light of the first wavelength. The amount of change in the effective attenuation coefficient is calculated from the intensity, and the blood lipid concentration is calculated from the amount of change in the effective attenuation coefficient, the blood vessel depth, and the diameter information.

Hereinafter, the lipid concentration calculation process by the control unit 4 will be described.

The embodiment is a non-invasive blood lipid concentration measuring device and method based on spatial decomposition measurement of backscattered light, targeting veins. An embodiment is a blood lipid concentration measuring device and method in which the depth and diameter of a vein are simultaneously estimated by measuring two wavelengths. In the embodiment, the diameter of the vein is estimated, but the present invention is not limited to this, and the thickness of the vein such as the radius of the vein may be estimated. Further, the blood vessel to be measured is not limited to a vein, and may be, for example, an artery at a shallow position.

In the embodiment, the control unit 4 calculates the _{effective attenuation coefficient μ eff} from the light intensity obtained at a wavelength (first wavelength) where the absorption of hemoglobin is small. _{Next, the control unit 4 corrects the effective attenuation coefficient μ eff} with the estimated values of the depth and diameter of the vein obtained by the measurement at the wavelength (second wavelength) where the absorption of hemoglobin is large, and the corrected effective attenuation coefficient μ. Calculate the lipid concentration from _eff.

First, the control unit 4 calculates the _{effective attenuation coefficient μ eff} from the light intensity obtained at a wavelength (first wavelength) in which hemoglobin absorption is small. In a uniform medium, the relationship between the backscattered light intensity R (ρ) and the entrance / exit distance ρ can be approximated by the following equation.

(Number 1)

Here, S ₀ represents the light source intensity, μ _a represents the absorption coefficient, and μ _eff represents the effective attenuation coefficient. μ _eff is a coefficient that depends on the scattering coefficient and the absorption coefficient. Normally, the red blood cell concentration is relatively stable, so the absorption coefficient does not change significantly. In that case, μ _eff depends largely only on the scattering coefficient. Therefore, the lipid concentration can be calculated by calculating _{μ eff} from the light intensity with respect to ρ. Further, in the embodiment, it may be expressed by turbidity or the like instead of the lipid concentration.

The distance ρ between entry and exit here is the first distance ρ ₁ described later. _{Further, the effective attenuation coefficient μ eff} calculated from the light intensity obtained at the first wavelength is defined as μ _{eff_1} (first effective attenuation coefficient).

Next, the control unit 4 calculates an estimated value of the depth and diameter of the vein from the _{effective attenuation coefficient μ eff} obtained by the measurement at the wavelength (second wavelength) where the hemoglobin is absorbed greatly.

Lipid concentration calculation largely depends on the depth and diameter of the vein. On the other hand, at wavelengths where the absorption of hemoglobin in the blood is large (second wavelength), the absorption in the vein is dominant, so the light entering the vein is almost attenuated, and even if the scattering, that is, the lipid concentration changes, it is measured. The change in μ _eff that is made is small. Therefore, at the second wavelength, the depth and diameter of the vein can be estimated independently of the lipid concentration.

_{The effective attenuation coefficient μ eff} when the distance between entry and exit is short is dominated by the characteristics of venous blood, and when the distance is long, the surrounding tissue outside the vein is dominant. _{Therefore, the control unit 4 calculates μ eff_n} (second effective attenuation coefficient) from the light intensity detected by the first light intensity detection unit 31 at a short distance, for example, 3 to 8 mm (first distance ρ _1). _{Μ eff_f} (third effective attenuation coefficient) is calculated from the light intensity detected by the second light intensity detection unit 32 at a long distance, for example, 10 to 15 mm (second distance ρ _2).

The first distance ρ ₁ is not limited to 3 to 8 mm, but the range is narrowed to about 4 to 7 mm, and when a shallow vein is assumed, it is approached to about 2 to 5 mm, and deep veins are targeted. In that case, the distance may be as far as 6 to 9 mm, and a suitable distance is determined according to the measurement at a fixed place of one individual to be measured. The same applies to the second distance ρ _2.

FIG. 4 is a vein depth / diameter estimation map. 4, in the absorption of hemoglobin is large wavelength 600 nm (the second _{_{wavelength), μ eff_n / μ eff_f μ}} eff_n for (second effective attenuation coefficient and the ratio of the third effective attenuation coefficient) (second effective attenuation coefficient) This is the first calibration data created / acquired in advance by changing the depth (blood vessel depth) and the diameter (blood vessel thickness) of the vein.

In FIG. 4, three calibration lines (A, B, C in the figure) are shown. The second effective attenuation coefficient μ _{eff_n} is dominated by the effective attenuation coefficient μ _eff of venous blood and largely depends on the diameter of the vein. Therefore, in FIG. 4, when the diameter of the vein increases to 1,2,3 mm, the calibration line shifts from A to B and from B to C in the vertical axis direction.

_{On the other hand, the ratio μ eff_n} / μ _{eff_f} between the second effective attenuation coefficient and the third effective attenuation coefficient is the ratio of venous blood to the surrounding medium and largely depends on the depth of the vein. If the vein is deep, it will be buried in the surrounding medium and the ratio will be small, and if it is shallow, the opposite will be true. _{This is a premise that the μ eff} of venous blood is large with respect to the surrounding medium, and it holds without any problem at the second wavelength. Thus, veins if _{_μ} eff_n / μ eff_f the horizontal axis is small deeply when _{_μ} eff_n / μ eff_f the horizontal axis is large becomes veins shallow calibration line in FIG.

If the horizontal axis depends only on the thickness of the vein and the vertical axis depends only on the depth of the vein, it is not necessary to create the map shown in FIG. 4, but in the case of an actual vein. The measured effective damping coefficient is affected by the mutual influence of thickness and depth, and it is not preferable to treat them independently. The distortion of the map in FIG. 4 represents their mutual influence.

The estimation map of FIG. 4 can be created in advance by _obtaining _{μ eff_n} and μ eff_f by numerical simulation while changing the diameter and depth of veins within the assumed range and plotting them in FIG. In principle, it can be created in advance for an actual human body by measuring the diameter and depth of veins in advance with a phantom model or an ultrasonic diagnostic apparatus, not by simulation but experimentally.

The control unit 4 calibrates the diameter and depth of the vein prepared in advance by changing the blood vessel depth and the blood vessel thickness with respect to the second effective attenuation coefficient with respect to the ratio of the second effective attenuation coefficient and the third effective attenuation coefficient. The first calibration data of the curve is stored, and the depth and diameter of the vein are calculated from _{μ eff_n} / μ _{eff_f} and μ _{eff_n based on the first calibration data.}

The diameter and depth of veins can be estimated in mm units from the estimation map in FIG. 4, but since the map in FIG. 4 is rough, linear interpolation (nonlinear interpolation is also possible) and diameter and depth to fill the roughness are possible. The diameter and depth may be obtained with an accuracy of about 1 to 2 digits after the decimal point in mm units by simulating by finely changing the interpolation value. The estimation map (first calibration data) of FIG. 4 is created for each vein diameter and stored in the RAM 44.

Next, the control unit 4 corrects the _{effective attenuation coefficient μ eff} with the estimated values of the vein depth and diameter obtained from the vein depth / diameter estimation map of FIG. 4, and changes the lipid concentration from the _{corrected μ eff.} Calculate the amount. FIG. 5 shows an example of a calibration curve of lipid concentration at a wavelength of 810 nm (first wavelength). The vertical axis of FIG. 5 _{shows the amount of change in μ eff_1} (first effective attenuation coefficient), and the horizontal axis shows the lipid concentration. FIG. 5 is a graph showing the state in which there is no lipid on each of the vertical and horizontal axes as the initial value and the amount of change thereafter. It is also possible to obtain the calibration line as an absolute value. This makes it possible to estimate the venous blood lipid concentration from the calibration curve corresponding to the previously obtained vein depth and diameter.

FIG. 5 is a group of blood lipid concentration calibration curves. FIG. 5 is the second calibration data prepared and acquired in advance for the lipid concentration with respect to the amount of change in the first effective attenuation coefficient by changing the blood vessel depth and the blood vessel thickness. The method of deriving the calibration line of FIG. 5 will be described. A calibration graph as shown in FIG. 5 obtained by changing the blood scattering coefficient corresponding to the lipid concentration on the horizontal axis _{for μ eff_1} (first effective attenuation coefficient) of the first wavelength in which the absorption of hemoglobin at the first distance is small. , Prepare a graph as shown in FIG. 5 for each vein diameter by a simulation in which the vein diameters are changed. Note that FIG. 5 shows the calibration lines in which the diameter of the vein is fixed at 2 mm and the depth (depth in the figure) is changed. A graph of the calibration line group as shown in FIG. 5 is created for each diameter of veins such as 1 mm and 3 mm in diameter (not shown). Actually, the graph of the calibration line group of FIG. 5 (second calibration data) is created for each vein diameter and stored in the RAM 44.

Then, the calibration group of FIG. 5 according to the vein diameter previously estimated by the vein depth / diameter estimation map of FIG. 4 is selected. Next, from the blood lipid concentration calibration curve group, select the calibration line of the vein depth (depth in the figure) previously estimated by the vein depth / diameter estimation map of FIG. 4, and select the first calibration line at that time. It can be converted to lipid concentration by _{μ eff_1} (first effective attenuation coefficient) obtained from the measured value of wavelength.

The control unit 4 stores the second calibration data of the blood lipid concentration prepared in advance by changing the blood vessel depth and the blood vessel thickness for the lipid concentration with respect to the amount of change in the first effective attenuation coefficient, and the second calibration is performed. Based on the data, the lipid concentration is calculated from the depth and diameter of the vein and μ _{eff_1 (first effective attenuation coefficient) obtained from the measured values of the first wavelength.}

Since the blood lipid concentration calibration curve group in FIG. 5 is rough, it may be interpolated by linear interpolation or detailed simulation as in the explanation of the calibration map in FIG.

In the blood lipid concentration measuring device 1 of the embodiment having the above configuration, the blood lipid concentration measuring device 1 executes the blood lipid concentration measuring process based on a preset program. FIG. 6 is a flowchart of the blood lipid concentration measurement process of the embodiment.

The irradiation unit irradiates the irradiation position 21 with continuous light (step 101). The irradiation unit 2 irradiates light having a first wavelength that is less absorbed by hemoglobin and light having a second wavelength that is more absorbed by hemoglobin.

The first light intensity detection unit 31 detects the light intensity at the first detection position 331, and the second light intensity detection unit 32 detects the light intensity at the second detection position 332 (step 102). _{The first distance ρ 1} between the irradiation position 21 and the first detection position 331 is the distance at which the characteristics of venous blood dominate, and the second distance ρ ₂ between the irradiation position 21 and the second detection position 332 is the first. It is a distance _{longer than 1 distance ρ 1} and a measurement result can be obtained in which the surrounding tissue outside the vein is dominant.

The control unit 4 calculates _{μ eff_1} from the intensity of the first wavelength (for example, 810 nm) at the first distance (for example, 3 to 8 mm). The control unit 4 calculates _{μ eff_n} from the intensity of the second wavelength (for example, 600 nm) at _{the first distance ρ 1 (for example, 3 to 8 mm).} The control unit 4 _{calculates μ eff_f} from the intensity of the second wavelength (for example, 600 nm) at _{the second distance ρ 2} (for example, 10 to 15 mm) (step 103). The calculation method of μ _{eff is described above.}

_{The control unit 4 has the vein depth and diameter from μ eff_n} / μ _{eff_f} and μ _{eff_n at} the second wavelength calculated based on the vein depth / diameter calibration data created and stored in advance as shown in FIG. Is estimated (step 104).

The control unit 4 uses the calculated vein depth and diameter and the amount of change _{in μ eff_1 at} the first wavelength based on the blood lipid concentration calibration data prepared and stored in advance as shown in FIG. Calculate the concentration (step 105).

As described above, according to the blood lipid concentration measuring device and its method of the present embodiment, it is possible to stably measure the blood lipid concentration.

Although the embodiment has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Blood lipid concentration measuring device 2 Irradiation unit 3 Light intensity detection unit 4 Control unit

Claims

An irradiation unit that irradiates the light of the first wavelength and the light of the second wavelength, which is absorbed by hemoglobin more than the first wavelength, at a predetermined position of the subject.
A light intensity detection unit that detects light intensities at a plurality of positions emitted from the subject at predetermined intervals or at continuous positions from the light irradiation position by the irradiation unit.
The blood vessel depth and blood vessel thickness are calculated from the light intensity of the second wavelength.
The amount of change in the first effective attenuation coefficient is calculated from the light intensity of the first wavelength.
A control unit that calculates the lipid concentration from the amount of change in the first effective attenuation coefficient, the blood vessel depth, and the blood vessel thickness.
Blood lipid concentration measuring device having.
The blood lipid concentration measuring apparatus according to claim 1, wherein the first wavelength is 750 nm or more and 850 nm or less, and the second wavelength is 500 nm or more and 600 nm or less.
The light intensity detection unit
The light intensity at the first distance from the irradiation unit and the second distance longer than the first distance is detected.
The control unit
The second effective attenuation coefficient of the first distance at the second wavelength and the third effective attenuation coefficient of the second distance at the second wavelength were calculated.
The blood vessel depth and the blood vessel thickness are calculated based on the ratio of the second effective attenuation coefficient and the third effective attenuation coefficient and the second effective attenuation coefficient.
The blood lipid concentration measuring device according to claim 1 or 2.
The control unit
The first calibration data prepared in advance by changing the blood vessel depth and the blood vessel thickness for the second effective damping coefficient with respect to the ratio of the second effective damping coefficient and the third effective damping coefficient is stored, and the first calibration data is stored. The third aspect of claim 3, wherein the blood vessel depth and the blood vessel thickness are calculated from the ratio of the second effective attenuation coefficient and the third effective attenuation coefficient and the second effective attenuation coefficient based on the calibration data. Blood lipid concentration measuring device.
The control unit
The lipid concentration with respect to the amount of change in the first effective attenuation coefficient is stored in the second calibration data prepared in advance by changing the blood vessel depth and the blood vessel thickness, and the first effective is based on the second calibration data. The blood lipid concentration measuring apparatus according to claim 4, wherein the lipid concentration is calculated from the amount of change in the attenuation coefficient, the blood vessel depth, and the blood vessel thickness.
The blood lipid concentration measuring device according to any one of claims 3 to 5, wherein the first distance is 3 mm or more and 8 mm or less, and the second distance is 10 mm or more and 15 mm or less.
The light of the first wavelength and the light of the second wavelength, which is absorbed by hemoglobin more than the first wavelength, are irradiated to a predetermined position of the subject.
By detecting the light intensities at a plurality of positions emitted from the subject at predetermined intervals from the light irradiation position or at continuous positions, the light intensity is detected.
The blood vessel depth and blood vessel thickness are calculated from the light intensity of the second wavelength.
The amount of change in the first effective attenuation coefficient is calculated from the light intensity of the first wavelength.
A method for measuring a blood lipid concentration, which calculates a lipid concentration from the amount of change in the first effective attenuation coefficient, the blood vessel depth, and the blood vessel thickness.