TW202215027A - Glucose quantity calculation method - Google Patents

Abstract

The present invention provides a method for calculating glucose quantity, which statistically uses the intensity of each light irradiated along an optical axis that penetrates a human body, so that the glucose quantity can be accurately measured. A method for calculating glucose quantity of the present invention includes the following steps: a step of irradiating a first light, a second light and a third light with different wavelengths on a measured part of a human body, and using a light receiving element to receive the first light, the second light and the third light that have penetrated the measured part; and a step of estimating the glucose quality from the received light intensities of the first light, the second light and the third light according to a conversion formula. Furthermore, in the present invention, the conversion formula uses the intensities of the first light, the second light and the third light with different wavelengths that have penetrated the human body, and a glucose quantity from blood-sampling as a measured data set, obtains multiple measured data sets for different glucose qualities, and performs a multiple regression analyses based on the multiple measured data sets.

Description

How to calculate the amount of glucose

The present invention relates to a glucose quantity calculation method for optically measuring the glucose quantity inside a part to be measured, such as a human body.

As a method for detecting the sugar content in the measurement site, there are an invasive method and a non-invasive method. The invasive method refers to a method in which blood is collected from, for example, a fingertip of a human body, and the amount of glucose is measured using the blood. The so-called non-invasive method refers to a method of measuring the amount of glucose with a sensor arranged outside the human body without taking blood from the human body. Although an invasive method is generally used to calculate the correct amount of glucose, a method for calculating the amount of glucose by a non-invasive method is desired in order to relieve the user's pain and improve convenience.

As an example of a method of measuring the amount of glucose by a non-invasive method, a method of optically measuring by irradiating a human body with near-infrared light or the like is known.

Moreover, as an optical measurement method of the amount of glucose, there is a method of detecting a difference in the amount of glucose absorbed by near-infrared light. Specifically, in this method, near-infrared light is transmitted at a certain location, and the amount of glucose is measured based on the amount of the transmitted light (for example, Patent Document 1 and Patent Document 2).

[Prior Art Literature]

[Patent Literature]

Patent Document 1: Japanese Patent No. 3093871

Patent Document 2: Japanese Patent No. 3692751

However, in the method for measuring the amount of glucose by the non-invasive method described in each of the above-mentioned patent documents, there is a problem that it is difficult to always accurately measure the amount of glucose.

Specifically, in the measurement method described in Patent Document 1, since the amount of glucose is calculated by the glucose oxidase method, there is a problem that the calculation of the amount of glucose is complicated. Further, in the method described in Patent Document 2, although the amount of glucose is measured by an optical method, it is to such an extent that the possibility of diabetes can be determined, and the amount of glucose cannot be quantitatively measured.

The present invention has been developed in view of such a problem, and an object of the present invention is to provide a method for calculating the amount of glucose, which statistically utilizes the received light intensity of each light beam irradiated along the optical axis passing through the human body, thereby enabling Correctly guess the amount of glucose.

The method for calculating the amount of glucose of the present invention includes: a measuring step of irradiating a plurality of light rays with different wavelengths on the measured part, and using a light-receiving element to measure the difference between the plurality of light rays having penetrated the above-mentioned measured part. The intensity; and the estimation step is to estimate the amount of glucose from the received light intensities of the plurality of light rays according to the conversion formula; in the measurement step, the plurality of light rays pass through an optical axis specified in a manner of penetrating the measured part.

In addition, in the method for calculating the amount of glucose of the present invention, in the aforementioned measuring step, the The aforementioned received light intensity, the temperature of the measured part, and the blood glucose amount of the plurality of rays are used as a measured data set, and a plurality of the aforementioned measured data sets are obtained for different glucose amounts, and multiple regression analysis is performed according to the aforementioned multiple measured data sets, Thereby, a plurality of the aforementioned conversion formulae are created; in the aforementioned estimation step, from the plurality of glucose amount estimation results calculated using the respective aforementioned conversion formulae, the aforementioned glucose amount estimation result closest to the blood collection glucose amount is selected, and will be calculated The conversion formula of the selected glucose amount estimation result is used for the next and subsequent glucose amount estimation.

In addition, in the method for calculating the amount of glucose of the present invention, in the measurement step, the temperature of the measured part is measured; in the estimation step, in addition to the received light intensities of the plurality of light rays, the temperature is also used to calculate the temperature. The aforementioned amount of glucose is calculated.

Moreover, in the glucose amount calculation method of this invention, the said conversion formula uses the parameter (parameter) memorize|stored in the memory|storage device in advance.

Furthermore, in the method for calculating the amount of glucose of the present invention, the plurality of light rays penetrate through the finger web (that is, the membrane-like portion formed between the fingers).

Moreover, in the glucose amount calculation method of this invention, the said conversion formula is a multiple regression formula calculated by a statistical method. In this way, according to the method for calculating the amount of glucose of the present invention, since the conversion formula is calculated according to the statistical method, the conversion formula according to the constitution of each subject can be obtained.

In addition, in the method for calculating the amount of glucose of the present invention, in the above-mentioned measuring step, the first light, the second light and the third light with different wavelengths are irradiated on the above-mentioned part to be measured, and the light-receiving element is used to measure the penetration The intensities of the first light, the second light and the third light behind the measured part; in the estimation step, according to the conversion formula, from the first light, the second light and the third light The amount of glucose was estimated from the received light intensity.

The method for calculating the amount of grapes according to the present invention includes: a measuring step of irradiating a plurality of light rays with different wavelengths on a measured part, and measuring the intensity of the plurality of light rays penetrating the measured part by a light-receiving element and the estimation step is to estimate the amount of glucose from the light-receiving intensities of the plurality of light rays according to the conversion formula; in the measurement step, the plurality of light rays pass through an optical axis specified in the manner of passing through the measured portion. Thus, according to the method for measuring the amount of glucose of the present invention, the amount of glucose can be accurately measured by passing the plurality of light rays through one optical axis and passing the plurality of light rays through the body part of the same optical condition.

In addition, in the method for calculating the amount of glucose of the present invention, in the measurement step, the received light intensity of the plurality of rays, the temperature of the measured part, and the amount of blood glucose collected are used as an actual measurement data set, and obtained for different amounts of glucose. A plurality of the above-mentioned measured data sets, and multiple regression analysis is performed according to the above-mentioned plurality of the above-mentioned measured data sets, thereby producing a plurality of the above-mentioned conversion formulas; in the above-mentioned estimation step, from the plurality of glucose calculated by using the respective above-mentioned conversion formulas As the amount estimation result, the glucose amount estimation result closest to the blood sampling glucose amount is selected, and the conversion formula for calculating the selected glucose amount estimation result is used for the next and subsequent glucose amount estimation. As a result, according to the method for measuring the amount of glucose of the present invention, by preparing a plurality of conversion formulas, an appropriate conversion formula can be adopted according to the constitution of the subject, so that the blood glucose level can be estimated with high accuracy.

In addition, in the method for calculating the amount of glucose of the present invention, in the measurement step, the temperature of the measured part is measured; in the estimation step, in addition to the received light intensities of the plurality of light rays, the temperature is also used to calculate the temperature. The aforementioned amount of glucose is calculated. Therefore, according to the method for measuring the amount of glucose of the present invention, the amount of glucose can be estimated more accurately by using the body temperature in addition to the received light intensity of the light penetrating the human body.

In addition, in the method for calculating the amount of glucose of the present invention, the aforementioned conversion formula is stored in advance using parameters in the memory device. Therefore, according to the method for measuring the amount of glucose of the present invention, the subject can obtain the conversion formula without taking blood.

Furthermore, in the method for calculating the amount of glucose of the present invention, the plurality of light rays penetrate the finger web. Therefore, according to the method for measuring the amount of glucose of the present invention, the amount of glucose is calculated by using each light penetrating the finger webs that have less fat, less thickness variation between individuals, and shorter penetration distances, so as to calculate the amount of glucose. The amount of glucose can be correctly estimated.

Moreover, in the glucose amount calculation method of this invention, the said conversion formula is a multiple regression formula calculated by a statistical method. In this way, according to the method for calculating the amount of glucose of the present invention, since the conversion formula is calculated according to a statistical method, a conversion formula according to the constitution of each subject can be obtained.

In addition, in the method for calculating the amount of glucose of the present invention, in the above-mentioned measuring step, the first light, the second light and the third light with different wavelengths are irradiated on the above-mentioned part to be measured, and the light-receiving element is used to measure the penetration The intensities of the first light, the second light and the third light at the measured part; in the estimation step, the light received from the first light, the second light and the third light according to the conversion formula Intensity estimates the aforementioned amount of glucose. Therefore, according to the method for calculating the amount of glucose of the present invention, the amount of glucose can be more accurately calculated by using the first light, the second light and the third light having different wavelengths.

10: Glucose amount calculation device

11: Light-emitting part

12: Operation input part

13: Memory Department

14: Lens

15: Display part

17: Operation Control Department

18: Measured part

19: Receiver

21: Temperature measurement section

22: Optical axis

111: The first light-emitting part

112: Second light-emitting part

113: The third light-emitting part

FIG. 1 is a conceptual diagram showing the basic configuration of a glucose amount measuring apparatus used in a method for calculating a glucose amount according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a method for calculating the amount of glucose according to the embodiment of the present invention.

3 is a schematic diagram showing a method for calculating the amount of glucose according to an embodiment of the present invention, wherein (A), (B) and (C) are side views showing the state of measurement while moving the light-emitting point.

FIG. 4 is a graph showing a method for calculating the amount of glucose according to the embodiment of the present invention.

5 is a schematic diagram showing a method for calculating the amount of glucose in another aspect of the present invention, wherein (A) is a flowchart, and (B) is a block diagram conceptually showing the method.

6 is a schematic diagram showing a method for calculating the amount of glucose according to an embodiment of the present invention, wherein (A) is a schematic diagram showing a finger web, (B) is a diagram showing the result of measuring the amount of glucose at the fingertip, (C) is A graph showing the results of measuring the amount of glucose in the fingertips.

The method for calculating the amount of glucose in this embodiment will be described with reference to FIG. 1 . FIG. 1 is a conceptual diagram showing the basic configuration of a glucose amount calculation device 10 used in the glucose amount calculation method of the present embodiment. Here, the amount of glucose refers to the amount of glucose in the blood or in the stroma. In addition, the amount of glucose may also be referred to as a blood sugar level or the like.

Referring to FIG. 1 , the glucose amount calculating device 10 includes a light emitting unit 11 that emits light used for measurement, and a lens 14 belonging to an optical element that guides the light emitted from the light emitting unit 11 to the measurement target. part 18; light receiving part 19, which receives the light passing through the measured part 18; arithmetic control part 17, which calculates the amount of glucose according to the output of the light receiving part 19; memory part 13; display part 15; operation input part 12; and temperature Measuring unit 21 .

The function of the glucose amount calculating device 10 is to measure the amount of glucose in the human body by a non-invasive method by allowing light to penetrate the human body belonging to the part to be measured.

The light emitting unit 11 emits light of a predetermined wavelength in order to measure the amount of glucose. Light-emitting part 11 has a first light emitting part 111, a second light emitting part 112 and a third light emitting part 113 which emit light with different wavelengths. The first light emitting part 111 , the second light emitting part 112 and the third light emitting part 113 are respectively composed of light emitting diodes. For example, the wavelength of the first light beam emitted from the first light-emitting portion 111 is 1310 nm, the wavelength of the second light beam emitted from the second light-emitting portion 112 is 1450 nm, and the wavelength of the third light beam emitted from the third light-emitting portion 113 is 1550nm.

Moreover, the light-emitting part 11 is moved to the left-right direction by the actuator (actuator) which is not shown in figure. By moving the light-emitting portion 11 , any one of the first light-emitting portion 111 , the second light-emitting portion 112 and the third light-emitting portion 113 can be arranged on the same axis of the optical axis 22 . Here, the case where the second light-emitting portion 112 is arranged on the axis of the optical axis 22 is shown.

The first light is light that is not absorbed by components in the living body, and the second and third light is light that is absorbed by glucose, protein, and water in the living body. Using the first light to measure the optical path length of the optical axis 22, the influence of the optical path length on the absorptivity of each light can be measured and the influence of the optical path length can be excluded, so that the amount of glucose can be calculated correctly.

In this embodiment, the first light, the second light and the third light are irradiated along the optical axis 22 from the light-emitting portion 11 to the light-receiving portion 19 . That is, the propagation paths and propagation lengths of the first light ray, the second light ray and the third light ray inside the measured portion 18 are the same.

By sharing the optical axis 22 in the above-mentioned manner, the glucose amount can be accurately measured. Specifically, the amount of glucose can be calculated by the following Equation 1 by the Lambert-Beer law.

Equation 1: C=-log ₁₀ (I/I _o )/(0.434×μ _a ×r)

In the above equation 1, C is the amount of glucose, I is the output light power, I _o is the incident light power, μ _a is the light absorption coefficient of the skin, and r is the optical path length.

In this embodiment, the optical path length r is set to be the same because the first light, the second light and the third light share the optical axis 22, thereby reducing the number of unknowns that should be calculated, which is accurate and simple to find the amount of glucose C.

The lens 14 guides the first light, the second light and the third light emitted from the first light emitting part 111, the second light emitting part 112 and the third light emitting part 113 by the refraction or diffraction effect thereof. Lead to the site to be measured 18 .

The portion to be measured 18 refers to a portion where the amount of glucose is measured by the glucose amount calculating device 10 of this type. Specifically, a fingertip, an earlobe, a finger web, or the like can be used as the part 18 to be measured. As will be described later, as the measurement site 18, a finger web that contains a small amount of fat, has a small individual difference in thickness, and does not have a thick blood vessel formed therein is preferable.

The light-receiving portion 19 is, for example, a semiconductor element composed of a photodiode, and is formed with a light-receiving portion (not shown) that receives the first light ray, the second light ray, and the first light ray that penetrate the measured portion 18 . Three rays, and their intensity is detected. The light receiving unit 19 transmits signals corresponding to the received light intensities of the first light, the second light and the third light to the arithmetic control unit 17 .

The memory unit 13 is a semiconductor memory device or the like composed of a RAM (Random Access Memory) or a ROM (Read Only Memory), and the memory is used to calculate the amount of glucose from the output value of the light receiving unit 19 . Calculation formula, parameters, estimated results, programs for executing the method for calculating the amount of glucose in this embodiment, and the like.

The operation input unit 12 is a site where the subject gives an instruction to the arithmetic control unit 17 , and is composed of a switch, a touch panel, and the like.

The temperature measuring part 21 is a part that measures the body temperature of the subject by touching the subject's body.

The calculation control unit 17 is constituted by a CPU (Central Processing Unit), performs various calculations, and controls the operation of each part constituting the glucose amount calculation device 10 . Specifically, the arithmetic control unit 17 emits the first light ray, the second light ray and the third light ray from the first light emitting unit 111 , the second light emitting unit 112 and the third light emitting unit 113 of the light emitting unit 11 . In addition, the arithmetic control unit 17 estimates the amount of glucose using a conversion equation belonging to a multiple regression equation, which will be described later, based on electrical signals input from the light receiving unit 19 and the temperature measuring unit 21 and the like. In addition, the calculation control unit 17 may display the calculated amount of glucose on the display unit 15 . By displaying the amount of glucose on the display unit 15 belonging to the liquid crystal monitor, for example, the user who uses the glucose amount calculating device 10 can instantly know the change in the amount of glucose in his/her own. In addition, in the step of performing the measurement described later, in order to arrange the light emitting points of the respective light emitting parts on the axis of the optical axis 22 , the arithmetic control part 17 moves the light emitting part 11 .

A method of estimating a subject's glucose amount using the glucose amount calculating device 10 will be described with reference to the flowchart of FIG. 2 and the above-described FIG. 1 . Here, the parameters belonging to the multiple regression equation used for the estimation of the glucose amount are calculated by the subject's blood collection and the irradiation of each light, and the test subject is estimated from the output value of the light receiving unit 19 using the conversion equation. the amount of glucose. Here, as the parameters of the multiple regression equation, the parameters previously stored in the memory unit 13 of the glucose amount calculation device 10 may be used, thereby improving the convenience of the subject. In addition, each of the following steps is executed in accordance with the program stored in the memory unit 13 .

In step S10, first, the amount of glucose is measured from the blood collected from the subject. This blood collection is used to calculate the parameters of the multiple regression equation, and blood collection is not required for the next and subsequent measurements because blood collection is performed first.

In step S11, the intensity and body temperature of the light passing through the finger webs of the subject are then measured. Specifically, the arithmetic control unit 17 is composed of the first light-emitting unit 111 , the second light-emitting unit 112 and the third light-emitting unit 111 of the light-emitting unit 11 . The light emitting part 113 emits the first light, the second light and the third light. The wavelengths of the first light, the second light and the third light are as described above. Then, as shown in FIG. 1 , the light-emitting portion 11 is moved along the left and right rear, thereby irradiating the first light beam, the second light beam and the third light beam along the optical axis 22 .

The radiated first light, second light and third light are irradiated on predetermined parts of the measured part 18 through the lens 14 . After the first light, the second light and the third light incident on the measured part 18 are absorbed, attenuated and reflected inside the human body, a part of them will penetrate the human body and reach the light receiving part 19 . The light receiving unit 19 transmits an electrical signal corresponding to the received light intensity to the arithmetic control unit 17 according to each wavelength band of the first light, the second light and the third light. Here, a pinhole can also be used instead of the lens 14 to adjust and irradiate each light.

The matter of irradiating each light beam while displacing the light emitting unit 11 in step S11 will be described with reference to FIG. 3 . FIG. 3(A) shows a state in which the second light is irradiated from the second light-emitting portion 112 , FIG. 3(B) shows a state in which the first light is irradiated from the first light-emitting portion 111 , and FIG. 3(C) shows a state in which the first light is irradiated from the third light-emitting portion 111 A state in which the light emitting unit 113 emits the third light beam. Here, although the second light-emitting portion 112, the first light-emitting portion 111, and the third light-emitting portion 113 are irradiated with light along the optical axis 22 in the order, the order can be changed.

3(A) , when the second light emitting portion 112 is irradiated with the second light, the calculation control portion 17 first moves the light emitting portion 11 so that the light emitting point of the second light emitting portion 112 overlaps with the optical axis 22 . After the light-emitting point of the second light-emitting portion 112 overlaps with the optical axis 22 , the arithmetic control portion 17 emits the second light from the second light-emitting portion 112 . The emitted second light beam travels along the optical axis 22 and irradiates the light receiving portion 19 after penetrating the measured portion 18 . An electrical signal representing the intensity of the second light beam received by the light receiving unit 19 is sent to the arithmetic control unit 17 .

Referring to FIG. 3(B), the arithmetic control unit 17 then moves the light-emitting unit 11 toward the right by an actuator not shown, whereby the light-emitting point of the first light-emitting unit 111 overlaps the axis of the optical axis 22 . in the first After the light-emitting point of the light-emitting portion 111 overlaps with the optical axis 22 , the arithmetic control portion 17 emits the first light from the first light-emitting portion 111 . The emitted first light beam travels along the optical axis 22 and irradiates the light receiving part 19 after penetrating the measured part 18 . An electrical signal representing the intensity of the first light beam received by the light receiving unit 19 is sent to the arithmetic control unit 17 .

Referring to FIG. 3(C) , the arithmetic control unit 17 then moves the light-emitting unit 11 to the left by an actuator not shown, whereby the light-emitting point of the third light-emitting unit 113 overlaps the axis of the optical axis 22 . After the light-emitting point of the third light-emitting portion 113 overlaps with the optical axis 22 , the arithmetic control portion 17 emits a third light beam from the third light-emitting portion 113 . The emitted third light beam travels along the optical axis 22 and irradiates the light receiving portion 19 after penetrating the measured portion 18 . An electrical signal representing the intensity of the third light beam received by the light receiving unit 19 is sent to the arithmetic control unit 17 .

In addition, the temperature measuring unit 21 measures the body temperature of the subject according to the instruction of the arithmetic control unit 17 , and an electrical signal representing the body temperature is sent to the arithmetic control unit 17 .

The above-mentioned step S11 is performed a plurality of times for a plurality of glucose amounts in order to perform a multiple regression analysis to be described later.

In step S12, the parameters of the multiple regression equation are obtained according to the result of step S11.

The amount of blood glucose and the like measured in step S11 are shown in Table 1 below.

[Table 1]

In Table 1, the amount of blood glucose, the temperature of the part to be measured, the received light intensity of the first light ray with a wavelength of 1310 nm, the received light intensity of the second light ray with a wavelength of 1450 nm, and the received light of the third light ray with a wavelength of 1550 nm are displayed from the left. strength and the estimated amount of glucose. Here, blood sampling, body temperature measurement, light reception of each light passing through the human body, and estimation of the glucose amount based on the received light intensity are performed while changing the blood glucose level of the subject by administration of sugar or the like.

In this embodiment, multiple regression analysis is performed based on the results of Table 1, and each parameter of the multiple regression formula belonging to the conversion formula is calculated. In the present embodiment, a multiple regression equation shown in the following equation 2 is used as a conversion equation for estimating the amount of glucose.

Equation 2: Estimated amount of glucose = slice + β 1 × temperature of the part to be measured + β 2 × first light output voltage + β 3 × second light output voltage + β 4 × third light output voltage

The parameters constituting Equation 2 are stored in the memory unit 13 and used for estimation of the amount of glucose.

The analysis results obtained by the above-mentioned multiple regression analysis are shown in Table 2 below. Table 2 includes Table 2-1, Table 2-2, and Table 2-3. Table 2-1 shows regression statistics, Table 2-2 shows dispersion analysis, Table 2-3 shows regression coefficients and the like obtained by regression analysis.

[Table 2]

As can be seen from Table 2, since all the P-values are 0.05 or less, the regression coefficient can be determined to be valid, and the glucose amount can be accurately estimated using the multiple regression equation shown in the above-mentioned Equation 2.

Fig. 4 is a graph showing the relationship between the estimated glucose amount and the blood sampling glucose amount. The horizontal axis of the graph shows the blood glucose level, and the vertical axis shows the estimated glucose level. In this graph, the calibration curve is represented by a solid line, and a line with a ±5% error is represented by a dotted line.

In step S13 and step S14, the amount of glucose is estimated using the above-mentioned conversion formula. Specifically, referring to FIG. 1 , the arithmetic control unit 17 firstly transmits the first light, The second light beam and the third light beam are irradiated toward the portion to be measured 18 . The first light, the second light and the third light are attenuated, reflected and absorbed inside the measured part 18, and a part of them will penetrate the measured part 18 and reach the light receiving part 19. The light receiving unit 19 transmits an electric signal indicating the intensities of the first light ray, the second light ray and the third light ray that have reached the light receiving unit 19 to the arithmetic control unit 17 . In addition, the electrical signal indicating the temperature of the measured part 18 measured by the temperature measuring unit 21 is also sent to the arithmetic control unit 17 . The arithmetic control unit 17 estimates glucose using the conversion formula shown in the above equation 2 based on the electrical signal representing the intensity of the first light, the second light and the third light, and the electrical signal representing the body temperature of the measured part 18 quantity.

Table 3 shows the results of estimating the amount of glucose by the same subjects as in Table 1 by the methods shown in steps S13 and S14 on different days. That is, here, the person who has performed blood collection, light irradiation, and body temperature measurement in order to derive the conversion formula is the same person who estimated the amount of glucose using the conversion formula. As can be understood from Table 3, since the estimated glucose amount estimated by the estimation method of the present embodiment is very close to the blood sampling glucose amount, it can be determined that an accurate estimation has been performed.

[table 3]

Table 4 shows the results of estimating the amount of glucose by the methods shown in steps S13 and S14 by subjects different from those in Table 1 (subjects for calculating the conversion formula). As can be seen from Table 4, even when the subject for which the conversion formula was derived and the subject for which the glucose amount was estimated using the conversion formula were different, since the estimated glucose amount and the blood sampling glucose amount were still close, so Even in this case, a correct guess is made.

[Table 4]

In addition, in the graph of FIG. 4 , the blood sampling glucose amount and the estimated glucose amount used for the calculation of the calibration curve are indicated by hollowed circles. In addition, the values of Table 4 and Table 5 are represented by black circles. As can be seen from this graph, the cases of other subjects and the measurement values of any day are arranged in the area enclosed by the line with an error of approximately ±5%. Therefore, the amount of glucose can be accurately estimated by the estimation method using the above-mentioned conversion formula.

Another method of estimating the amount of glucose will be described with reference to FIG. 5 . The outline of the method for estimating the amount of glucose described here is the same as that described above, but the matter of improving the estimation accuracy by preparing a plurality of conversion formulae and selecting a conversion formula suitable for the subject is different from the above-described method. FIG. 5(A) is a flowchart showing a method of estimating the amount of glucose in this embodiment, and FIG. 5(B) is a block diagram conceptually showing a calculation method in this embodiment.

Referring to FIG. 5(A), in step S20, a plurality of conversion expressions are prepared. Specifically, as shown in FIG. 5(B) , a plurality of multiple regression equations are obtained by performing blood collection, application of each light using the glucose amount calculation device 10, and body temperature measurement for different subjects. Here, subject A, subject B, subject C, and subject D are subjected to irradiation of each light, body temperature measurement, and multiple regression analysis to obtain the first light, The measured data set composed of the received light intensity of the second light and the third light and the body temperature. The multiple regression formula A, the multiple regression formula B, the multiple regression formula B, the multiple regression formula B, the multiple regression formula B, the multiple Parameters of regression C and multiple regression D.

In steps S21 and S22, the estimated glucose amount A and the estimated glucose amount B are estimated by using the glucose amount calculating device 10 and using the multiple regression equation A, the multiple regression equation B, the multiple regression equation C, and the multiple regression equation D. , the estimated amount of glucose C and the estimated amount of glucose D. Specifically, referring to FIG. 1 , the arithmetic control unit 17 first transmits the first light ray, the second light emitting unit 112 and the third light emitting unit 113 to the measured part 18 along the optical axis 22 from the first light emitting unit 111 , the second light emitting unit 112 and the third light emitting unit 113 of the light emitting unit 11 . The second light beam and the third light beam are irradiated toward the portion to be measured 18 . The light receiving unit 19 transmits an electric signal indicating the intensities of the first light ray, the second light ray and the third light ray that have reached the light receiving unit 19 to the arithmetic control unit 17 . In addition, the electrical signal indicating the temperature of the measured part 18 measured by the temperature measuring unit 21 is also sent to the arithmetic control unit 17 . Next, the arithmetic control unit 17 uses the multiple regression formula A, the multiple regression formula B, the multiple regression formula A, the multiple regression formula B, the multiple regression formula B, the multiple regression formula B, The regression equation C and the multiple regression equation D are used to estimate the estimated glucose amount A, the estimated glucose amount B, the estimated glucose amount C, and the estimated glucose amount D. Furthermore, in order to perform the selection in step S23, blood is collected from the subject to obtain the blood glucose amount.

In step S23, the estimated glucose amount closest to the blood sampling glucose amount among the estimated glucose amount A, the estimated glucose amount B, the estimated glucose amount C, and the estimated glucose amount D is selected. This selection is performed by the operation of the operation input unit 12 by the subject or the calculation control unit 17 . For example, if the estimated glucose amount A is closest to the blood sampling glucose amount, the multiple regression equation A is used to estimate the glucose amount from the next estimation by the subject's selection of the operation input unit 12 .

In step S24, the selected multiple regression formula A is used to estimate the amount of glucose. Specifically, the arithmetic control unit 17 firstly transmits the first light, the second light, and the The third light beam is irradiated toward the measurement site 18 . In addition, the electrical signal indicating the temperature of the measured part 18 measured by the temperature measuring unit 21 It is also sent to the arithmetic control unit 17 . The arithmetic control unit 17 estimates the amount of glucose by using the multiple regression formula A selected as described above based on the electrical signal representing the intensities of the first light, the second light and the third light and the electrical signal representing the body temperature of the measured part 18 .

Referring to FIG. 6 , a description will be given of the fact that the finger web is suitable as a measurement site to be irradiated with each light for estimating the amount of glucose. Fig. 6(A) is a schematic diagram showing the subject's hand, Fig. 6(B) is a graph showing an error grid after estimating the amount of glucose using the fingertip, and Fig. 6(C) is a graph showing an error grid using the fingertip A graph of the error grid after fingering the web to estimate the amount of glucose. In FIG. 6(B) and FIG. 6(C) , the horizontal axis represents the blood glucose level, and the vertical axis represents the estimated glucose level measured by the method of this embodiment.

Referring to FIG. 6(A), the so-called webs refer to the membrane-like parts formed between the fingers of the human body. In this embodiment, the webs formed between the index finger and the thumb of the hand are used as The measurement site where the amount of glucose is measured. Here, the webs formed between the other fingers can also be used as the measurement site.

When referring to FIG. 6(B) , dots representing the measurement results are distributed away from the reference line indicated by the dotted line. The reason for this is that the individual differences in the thickness of the fingertips are large and the optical path lengths will vary accordingly, and that the thicker blood vessels existing in the fingertips may have adverse effects.

On the other hand, when referring to FIG. 6(C), the points representing the measurement results are distributed in the vicinity of the reference line shown by the dotted line. The reason for this is that because the thickness of the web is about 2mm to 4mm, the difference between individuals is small, the fat content is very small, and there are no thick blood vessels inside, so it can be measured in the capillaries and dermis. Furthermore, when finger webs are used as the measurement site, the optical path length can be shortened, and the amount of glucose can be measured with low-output light.

Referring to Table 5, the appropriateness of the finger web as the measurement site will be described from the viewpoint of the fat content.

[table 5]

In Table 5, the first ray was measured for specimen 1 with fat (epidermal 0.2 mm, dermis 0.8 mm, fat 1.5 mm), and specimen 2 without fat (epidermal 0.2 mm, dermis 0.8 mm, no fat) , the results of the transmittance of the second light and the third light. When an example is displayed, the specimen 1 is a fingertip of a human body, and the specimen 2 is a finger web.

1.5mm，受光面直徑為

3mm或

1mm。 The simulation conditions here are as follows: the number of light lines is 5000, the number of scattering times is 1000 times, and the incident light path of the skin is

1.5mm, the diameter of the light-receiving surface is

3mm or

1mm.

As shown in Table 5, in the first light beam having a wavelength of 1310 nm, the transmittance of the specimen 2 is 3.4 times the transmittance of the specimen 1 . Also, in the second light beam having a wavelength of 1450 nm, the transmittance of the specimen 2 is 6.2 times the transmittance of the specimen 1 . Furthermore, in the third light having a wavelength of 1550 nm, the transmittance of the specimen 2 is 3.5 times the transmittance of the specimen 1 .

According to the above, the specimen 1 belonging to, for example, a fingertip is not suitable as a part for measuring the amount of glucose because the transmittance of the first light to the third light is low. Moreover, it can be understood that when the individual difference in fat content is considered, the amount of fat will affect the penetration rate, and the estimation of the amount of glucose will be accordingly. become difficult.

On the other hand, the specimen 2 belonging to the finger web has very little fat content, so the first light, the second light and the third light can penetrate well, and can be accurately penetrated according to the intensity of each light. predict the amount of glucose. Also, even if the subject is obese, the fat contained in the finger webs does not increase extremely. Therefore, as long as the amount of glucose is estimated using each light penetrating the web, the amount of glucose can be accurately estimated regardless of whether the subject is obese or not.

Although the embodiment of the present invention has been shown above, the present invention is not limited to the above-described embodiment.

For example, in the above-mentioned embodiment, although the first light, the second light and the third light with different wavelengths have been used to calculate the amount of glucose, two light rays (for example, the first light with a wavelength of 1310 nm, The third light with a wavelength of 1550 nm) was used to calculate the amount of glucose.

10: Glucose amount calculation device

11: Light-emitting part

12: Operation input part

13: Memory Department

14: Lens

15: Display part

17: Operation Control Department

18: Measured part

19: Receiver

21: Temperature measurement section

22: Optical axis

111: The first light-emitting part

112: Second light-emitting part

113: The third light-emitting part

Claims (7)

A method for calculating the amount of glucose, comprising: In the measuring step, a plurality of light rays with different wavelengths are irradiated on the part to be measured, and a light-receiving element is used to measure the intensity of the plurality of light rays penetrating the part to be measured; and The estimation step is to estimate the amount of glucose from the received light intensities of the plurality of light rays according to the conversion formula; In the aforementioned measuring step, the aforementioned plurality of light rays pass through an optical axis defined in such a way as to penetrate through the aforementioned portion to be measured. The method for calculating the amount of glucose according to claim 1, wherein, in the measurement step, the received light intensity, the temperature of the measured part, and the glucose amount in the blood collection of the plurality of light rays are used as an actual measurement data set, and different The amount of glucose obtains a plurality of the above-mentioned measured data sets, and performs multiple regression analysis according to the above-mentioned plurality of measured data sets, thereby producing a plurality of the above-mentioned conversion formulas; In the estimation step, the estimation result of the glucose amount closest to the blood sampling glucose amount is selected from a plurality of estimation results of the amount of glucose calculated using the respective conversion equations, and the selected estimation result of the amount of glucose is calculated. The aforementioned conversion formula is used for the estimation of the amount of glucose after the next time. The method for calculating the amount of glucose according to claim 1 or 2, wherein, in the aforementioned measuring step, the temperature of the aforementioned portion to be measured is measured; In the estimation step, the amount of glucose is calculated using the temperature in addition to the received light intensity of the plurality of light rays. The method for calculating the amount of glucose according to claim 1, wherein the conversion formula uses parameters previously stored in a memory device. The method for calculating the amount of glucose according to any one of claims 1 to 4, wherein the plurality of light rays penetrate the finger webs. The method for calculating the amount of glucose according to any one of claims 1 to 5, wherein the conversion formula is a multiple regression formula calculated by a statistical method. The method for calculating the amount of glucose according to any one of claims 1 to 6, wherein, in the measurement step, the first light, the second light and the third light with different wavelengths are irradiated on the measured part, and using a light-receiving element to measure the intensity of the first light, the second light and the third light passing through the measured part; In the estimation step, the amount of glucose is estimated from the received light intensities of the first light, the second light and the third light according to the conversion formula.

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