JP2003194714A - Measuring apparatus for blood amount in living-body tissue - Google Patents

Measuring apparatus for blood amount in living-body tissue

Info

Publication number
JP2003194714A
JP2003194714A JP2001400431A JP2001400431A JP2003194714A JP 2003194714 A JP2003194714 A JP 2003194714A JP 2001400431 A JP2001400431 A JP 2001400431A JP 2001400431 A JP2001400431 A JP 2001400431A JP 2003194714 A JP2003194714 A JP 2003194714A
Authority
JP
Japan
Prior art keywords
amount
light
red blood
tissue
blood cells
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2001400431A
Other languages
Japanese (ja)
Inventor
Susumu Kajima
進 鹿嶋
Kentaro Mitsui
顕太郎 満井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
OMEGA WAVE KK
Original Assignee
OMEGA WAVE KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by OMEGA WAVE KK filed Critical OMEGA WAVE KK
Priority to JP2001400431A priority Critical patent/JP2003194714A/en
Publication of JP2003194714A publication Critical patent/JP2003194714A/en
Pending legal-status Critical Current

Links

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus for a blood amount in a living-body tissue by which an oxygenated red corpuscle amount, a deoxygenated red corpuscle amount and an oxygen saturation degree can be measured precisely without being influenced by a difference in the absorption degree of light inside the living-body tissue. <P>SOLUTION: The measuring apparatus is provided with a measuring-light output part in which three or more kinds of optical light sources 11, 12 and 13 are irradiated directly at the living-body tissue 8 at a prescribed intensity; a detection part 7a and a detection part 7b in which the intensity of transmitted and scattered light due to the passage of output measuring light through the tissue 8 is detected in two or more measuring points; a computing part 17a and a computing part 17b, in which the oxygenated red corpuscle amount in the tissue 8, the deoxygenated red corpuscle amount and an oxygenation degree as the ratio of the oxygenated red corpuscle amount to a total red corpuscle amount, or an oxygenation degree as the ratio of an oxygenated hemoglobin amount to a total hemoglobin amount, are computed on the basis of the light absorption amount in the tissue 8 obtained from the intensity difference between the output measuring light and the detected transmitted and scattered light; and a correction part 20 which corrects an error generated by the light absorption degree of the tissue 8 itself, with reference to respective measured values computed from the two or more measuring points. <P>COPYRIGHT: (C)2003,JPO

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【発明の属する技術分野】本発明は、医用機器の光計測
技術に係り、特に生体組織中の血液量測定や血液酸素化
度合測定等に用いられる生体組織血液量測定装置に関す
るものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring technique for medical equipment, and more particularly to a biological tissue blood volume measuring apparatus used for measuring blood volume in biological tissue, blood oxygenation degree and the like.

【0002】[0002]

【従来の技術】運動前および運動後の生体組織中の赤血
球(またはヘモグロビン)に可視光または近赤外領域の
特定波長の光を透過させると、運動前と運動後とでは光
吸収スペクトルが異なることは知られている。これは、
運動前と運動後とで酸素化赤血球の量と脱酸素化赤血球
の量が変動し、それが光吸収量の変化として表れるから
である。
2. Description of the Related Art When red blood cells (or hemoglobin) in a living tissue before and after exercise are made to transmit visible light or light having a specific wavelength in the near infrared region, the light absorption spectra before and after exercise are different. It is known. this is,
This is because the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells change before and after exercise, which appears as a change in the amount of light absorption.

【0003】そこで、生体組織中の赤血球に可視光また
は近赤外領域の特定波長の光を透過させ、赤血球量(ま
たはヘモグロビン量)の変動と光吸収量の変化との関係
を用いて、生体組織中の赤血球量の変動を測定する方法
および装置が提案されている。
Therefore, erythrocytes in living tissues are made to transmit visible light or light having a specific wavelength in the near-infrared region, and the relationship between the change in the amount of red blood cells (or the amount of hemoglobin) and the change in the amount of light absorption is used to determine whether or not the living body is living. Methods and devices have been proposed to measure variations in red blood cell mass in tissues.

【0004】例えば、従来の生体組織中血球量の変動を
測定する装置は、図6に示すように、生体組織(以下、
組織という)8に対し3種類の互いに波長の近い可視光
または近赤外線の光源11,12,13を所定の強度で
直接照射する測定光出力部と、出力された光源11,1
2,13の測定光(以下、測定光a,b,cとする)が
組織8を通過した透過散乱光の強度を検出する検出部
3,5,7,16と、出力された測定光a,b,cと検
出された透過散乱光の強度から酸素化度合、酸素化ヘモ
グロビン量と脱酸素化ヘモグロビン量を演算する酸素化
度合演算部17とを備えている。
For example, as shown in FIG. 6, a conventional device for measuring the fluctuation of blood cells in a living tissue,
(Tissue) 8 measuring light output section for directly irradiating three kinds of visible light or near infrared light sources 11, 12 and 13 having wavelengths close to each other with a predetermined intensity, and output light sources 11 and 1
Detectors 3, 5, 7 and 16 for detecting the intensities of the transmitted and scattered light in which the measurement lights 2 and 13 (hereinafter referred to as measurement lights a, b and c) have passed through the tissue 8 and the output measurement light a , B, c, and an oxygenation degree calculator 17 for calculating the oxygenation degree, the amount of oxygenated hemoglobin, and the amount of deoxygenated hemoglobin from the detected intensities of the transmitted scattered light.

【0005】光源11,12,13には、駆動回路19
より駆動電流が供給され、光源11,12,13は、集
光器にて集光されて光合波器15へ送られる。そして、
この光合波器15は、集光された測定光a,b,cを光
コネクタ2を介して1本、または複数本の光ファイバー
4に導光する。なお、各光源は、タイミング回路18が
指定する時分割で時間をずらして供給される駆動回路1
9の駆動電流により発光され、光コネクタ2を介して光
ファイバー4に導光する。
The light source 11, 12, 13 includes a drive circuit 19
A driving current is supplied from the light sources 11, 12, and 13, and the light sources 11, 12, and 13 are condensed by a condenser and sent to the optical multiplexer 15. And
The optical multiplexer 15 guides the condensed measurement light a, b, c to one or a plurality of optical fibers 4 via the optical connector 2. It should be noted that each light source is supplied with a time shift specified by the timing circuit 18 with a time shift.
It is emitted by the drive current of 9 and guided to the optical fiber 4 via the optical connector 2.

【0006】そして、組織8中を散乱、透過してきた測
定光は、光照射点(プローブ6)から所定距離(例え
ば、数mmから数cm程度)離れて設置された光検出器
7(または本体内の光検出器3に接続されている受光フ
ァイバープローブ)によって受光される。
The measuring light scattered and transmitted through the tissue 8 is a photodetector 7 (or main body) installed at a predetermined distance (for example, from several mm to several cm) from the light irradiation point (probe 6). The light is received by the light receiving fiber probe connected to the photodetector 3 inside.

【0007】酸素化血液(または酸素化ヘモグロビン)
と脱酸素化血液(または脱酸素化ヘモグロビン)の光吸
収スペクトルは異なっており、3種類以上の異なる波長
の光吸収度合を調べることで、測定対象とする組織中の
酸素化赤血球量と脱酸素化赤血球量、またはそれら変化
を求めることができる。
Oxygenated blood (or oxygenated hemoglobin)
And deoxygenated blood (or deoxygenated hemoglobin) have different light absorption spectra. By examining the light absorption degree of three or more different wavelengths, the amount of oxygenated red blood cells in the tissue to be measured and deoxidation The amount of red blood cells, or their changes, can be determined.

【0008】ところで、光検出器7で受光される測定光
は組織8中の血液による吸収のみでなく、組織内部の散
乱によっても減衰した光である。従って、検出される光
は一般的に[数式1]にて表すことができる。
The measuring light received by the photodetector 7 is not only absorbed by the blood in the tissue 8 but also attenuated by scattering inside the tissue. Therefore, the detected light can be generally expressed by [Formula 1].

【0009】[0009]

【数1】 [Equation 1]

【0010】なお、[数式1]において、Iは光検出器
7で検出された受光(透過光)強度を示し、ηは光シス
テムに関わる係数を示し、I0 は照射した測定光強度を
示し、exp( )は指数関数を意味する。
In [Equation 1], I represents the intensity of received light (transmitted light) detected by the photodetector 7, η represents a coefficient relating to the optical system, and I 0 represents the intensity of the measured light emitted. , Exp () means exponential function.

【0011】また、αは単位体積、単位光路長当たりの
酸素化赤血球の吸収係数を示し、V 1 は単位体積当た
りの酸素化赤血球の量を示し、βは単位体積、単位光路
長当たりの脱酸素化赤血球の吸収係数を示し、V2 は単
位体積当たりの脱酸素化赤血球の量を示し、μは単位長
当たりの組織の、散乱係数を示し、Lは照射点と受光点
間の距離(光路長)を示す。
Further, α is per unit volume and unit optical path length.
Shows the absorption coefficient of oxygenated red blood cells, V 1Is the unit volume
Is the amount of oxygenated red blood cells, β is the unit volume, unit optical path
Shows the absorption coefficient of deoxygenated red blood cells per length, V2 Is simply
Indicates the amount of deoxygenated red blood cells per unit volume, μ is the unit length
Shows the scattering coefficient of the tissue per hit, L is the irradiation point and the light receiving point
Indicates the distance (optical path length) between them.

【0012】ここで、[数式1]は各測定光毎に得られ
る式であり、各測定光波長におけるα、βを代入して酸
素化赤血球量や脱酸素化赤血球量を求めている。各測定
光波長のα、βの値は既知である。従って、未知数はV
1,V2とμの3種類であるために3つの方程式が必要と
なる。そこで、測定光は通常3種類以上となる。また、
μは各測定光波長が互いに近接しておれば、同じ値とし
て近似できる。
Here, [Equation 1] is an equation obtained for each measuring light, and the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells are obtained by substituting α and β for each wavelength of the measuring light. The values of α and β of each measurement light wavelength are known. Therefore, the unknown is V
Three equations are necessary because there are three types, 1 , V 2 and μ. Therefore, there are usually three or more types of measuring light. Also,
If the measurement light wavelengths are close to each other, μ can be approximated as the same value.

【0013】演算処理回路17は、組織8中の酸素化赤
血球量、脱酸素化赤血球量および血液の酸素化度合(酸
素化赤血球量V1 と脱酸素化赤血球量V2の比率で、V
1 /(V1+V2)として求められる)を求めるものであ
る。
The arithmetic processing circuit 17 calculates the amount of oxygenated red blood cells in the tissue 8, the amount of deoxygenated red blood cells, and the degree of oxygenation of blood (the ratio of the amount of oxygenated red blood cells V 1 to the amount of deoxygenated red blood cells V 2 , V
1 / (V 1 + V 2 )).

【0014】そして、[数式1]において、酸素化赤血
球の吸収係数α及び脱酸素化赤血球の吸収係数βは、図
8の波長特性図に示すように、分光光度計等で測定可能
な数値である。
In [Equation 1], the absorption coefficient α of oxygenated red blood cells and the absorption coefficient β of deoxygenated red blood cells are numerical values that can be measured by a spectrophotometer or the like, as shown in the wavelength characteristic diagram of FIG. is there.

【0015】次に、3種類の測定光によって得られた受
光量から連立方程式を解くと、次の[数式2]と[数式
3]が得られる。
Next, when the simultaneous equations are solved from the received light amounts obtained by the three kinds of measuring light, the following [Equation 2] and [Equation 3] are obtained.

【0016】[0016]

【数2】 [Equation 2]

【数3】 [Equation 3]

【0017】そこで、光路長Lの値を[数式2]と[数
式3]に代入することで、酸素化赤血球量や脱酸素化赤
血球量が求められる。
Therefore, by substituting the value of the optical path length L into [Equation 2] and [Equation 3], the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells can be obtained.

【0018】なお、[数式2]及び[数式3]におい
て、I1,I2およびI3 は光検出器7で検出された測
定光1,2,および3の受光(透過光)強度を示し、I
10,I 20およびI30は照射した測定光1,2,および3
の照射光強度を示し、Lnは自然対数を示し、A,B,
C及びDはα1,α2,α3 およびβ1,β2,β3 で表
される係数を意味する。
In addition, in the [Equation 2] and [Equation 3]
I1, I2And I3Is measured by the photodetector 7.
Indicates the intensity of received light (transmitted light) of constant light 1, 2, and 3, and I
Ten, I 20And I30Is the measuring light 1, 2, and 3 which is irradiated
Of the irradiation light, Ln represents a natural logarithm, A, B,
C and D are α1, Α2, Α3 And β1, Β2, Β3Table
Means the coefficient to be applied.

【0019】[0019]

【発明が解決しようとする課題】ところで、組織8内を
透過する透過光の強度は、組織8中の赤血球による吸収
のみでなく、組織8自体による吸収によっても減衰す
る。そして、生体組織自体による吸収度は組織毎に異な
り未知数である。
The intensity of the transmitted light passing through the tissue 8 is attenuated not only by the red blood cells in the tissue 8 but also by the tissue 8 itself. The degree of absorption by the living tissue itself is an unknown number, which varies from tissue to tissue.

【0020】しかしながら、従来の測定方法では、組織
8自体による光の吸収が各測定光において同じと仮定し
ており、生体組織自体の吸収度合の違いにより測定値に
誤差が生じてしまう。特に、皮膚ではメラニン色素によ
って光が吸収され、その吸収度合が波長によって異なっ
ており、更に可視光領域ではその影響が大きくなり、酸
素化赤血球量、脱酸素化赤血球量および酸素飽和度のよ
り精度の高い測定が非常に困難であった。
However, in the conventional measuring method, it is assumed that the absorption of light by the tissue 8 itself is the same in each measuring light, and an error occurs in the measured value due to the difference in the absorption degree of the living tissue itself. In particular, light is absorbed by the melanin pigment in the skin, and the degree of its absorption varies depending on the wavelength.In addition, the influence becomes greater in the visible light region, and the accuracy of oxygenated red blood cell amount, deoxygenated red blood cell amount and oxygen saturation is more accurate. Was very difficult to measure.

【0021】そこで、生体組織内の酸素化赤血球量(ま
たは酸素化ヘモグロビン量)、脱酸素化赤血球量(また
は脱酸素化ヘモグロビン量)とその割合を示す血液酸素
化度合をより正確に測定する技術の開発が求められてい
る。
Therefore, a technique for more accurately measuring the oxygenation degree of blood, which indicates the amount of oxygenated red blood cells (or the amount of oxygenated hemoglobin), the amount of deoxygenated red blood cells (or the amount of deoxygenated hemoglobin) and the ratio thereof in living tissues. Development is required.

【0022】本発明は、上記の事項に鑑みて改良を加え
たものであり、生体組織内の光の吸収度合の違いに影響
されずに、より正確な酸素化赤血球量、脱酸素化赤血球
量および酸素飽和度を測定できる生体組織血液量測定装
置を提供することを課題とする。
The present invention has been improved in view of the above matters, and is more accurate in the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells without being affected by the difference in the degree of light absorption in living tissue. Another object of the present invention is to provide a biological tissue blood volume measuring device capable of measuring oxygen saturation.

【0023】[0023]

【課題を解決するための手段】前記課題を解決するため
に、本発明の生体組織血液量測定装置は、以下の手段を
採用した。すなわち、本発明の生体組織血液量測定装置
は、3種類以上の測定光を所定の強度で生体組織に対し
直接照射する測定光出力部と、前記出力された測定光が
前記生体組織を通過した透過散乱光の強度を2点以上の
測定点で検出する検出部と、前記出力された測定光と前
記検出された透過散乱光の強度差から得られる前記生体
組織中の光吸収量に基づき前記生体組織中の全血液の酸
素化度合、または全赤血球量(または全ヘモグロビン
量)に対する酸素化赤血球量(または酸素化ヘモグロビ
ン量)の割合である酸素化度合、酸素化赤血球量(また
は酸素化ヘモグロビン量)と脱酸素化赤血球量(または
脱酸素化ヘモグロビン量)を演算する酸素化度合演算部
と、前記2点以上の測定点から、前記演算した酸素化度
合、酸素化赤血球量と脱酸素化赤血球量に対し生体組織
自体の光吸収度合より生じる誤差を補正する補正部とを
備えたことを特徴とする。
In order to solve the above problems, the biological tissue blood volume measuring device of the present invention employs the following means. That is, the biological tissue blood volume measuring device of the present invention is a measurement light output unit that directly irradiates the biological tissue with three or more types of measurement light at a predetermined intensity, and the output measurement light passes through the biological tissue. A detection unit that detects the intensity of transmitted scattered light at two or more measurement points, and the amount of light absorption in the biological tissue obtained from the intensity difference between the output measured light and the detected transmitted scattered light Oxygenation degree of whole blood in living tissue, or oxygenation degree, which is the ratio of oxygenated red blood cell amount (or oxygenated hemoglobin amount) to total red blood cell amount (or total hemoglobin amount), oxygenated red blood cell amount (or oxygenated hemoglobin) Amount) and the amount of deoxygenated red blood cells (or the amount of deoxygenated hemoglobin), and the calculated oxygenation degree, the amount of oxygenated red blood cells and deoxygenation from the two or more measurement points. Characterized in that a correction unit to correct an error arising from the light absorption degree of the living tissue itself to blood quantity.

【0024】なお、本発明の生体組織血液量測定装置に
おいて、前記補正部は、前記測定点が2点の場合、前記
測定値の差分を求めて前記誤差を補正するように構成し
てもよい。また、前記補正部は、前記測定点が3点以上
の場合、回帰式から前記測定値の回帰直線の傾きを求め
て前記誤差を補正するように構成してもよい。
In the biological tissue blood volume measuring device of the present invention, the correction unit may be configured to calculate the difference between the measured values and correct the error when the number of the measured points is two. . Further, the correction unit may be configured to calculate the slope of the regression line of the measurement value from a regression equation and correct the error when the number of measurement points is three or more.

【0025】この構成によれば、2個以上の検出部を光
照射点から異なる場所に設置して、それぞれの検出点で
受光した光強度から酸素化赤血球量と脱酸素化赤血球量
を求め、それぞれの光検出点で求めた酸素化赤血球量と
脱酸素化赤血球量には光吸収度合の違いによる誤差(オ
フセット値)を含んでいるが、その差分を計算すること
で、組織自体の吸収係数が不明でも、誤差(オフセット
値)を消去した正確な酸素化赤血球量と脱酸素化赤血球
量を得ることができる。または、検出部が3個以上の場
合は、回帰式を求めてその傾きから正確な酸素化赤血球
量と脱酸素化赤血球量を得ることができる。なお、光照
射点から検出部までの距離は既知、または測定可能であ
るために、酸素化赤血球量と脱酸素化赤血球量を距離L
で規格化することが可能である。
According to this structure, two or more detection units are installed at different positions from the light irradiation point, and the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells are obtained from the light intensity received at each detection point, The amount of oxygenated red blood cells and the amount of deoxygenated red blood cells obtained at each light detection point include an error (offset value) due to the difference in the degree of light absorption. By calculating the difference, the absorption coefficient of the tissue itself Even if is unknown, it is possible to obtain accurate oxygenated red blood cell amounts and deoxygenated red blood cell amounts with the error (offset value) eliminated. Alternatively, when there are three or more detection units, it is possible to obtain the accurate oxygenated red blood cell amount and deoxygenated red blood cell amount from the slopes of the regression equation. Since the distance from the light irradiation point to the detection unit is known or measurable, the oxygenated red blood cell amount and the deoxygenated red blood cell amount are separated by the distance L.
Can be standardized.

【0026】[0026]

【発明の実施の形態】次に、本発明の実施の形態にかか
る生体組織血液量測定装置を図面に基づき説明する。な
お、この装置は、生体組織内の酸素化赤血球量(または
酸素化ヘモグロビン量)、脱酸素化赤血球量(または脱
酸素化ヘモグロビン量)とその割合を示す血液酸素化度
合を直接測定するものである。
BEST MODE FOR CARRYING OUT THE INVENTION Next, a biological tissue blood volume measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that this device directly measures the amount of oxygenated red blood cells (or the amount of oxygenated hemoglobin), the amount of deoxygenated red blood cells (or the amount of deoxygenated hemoglobin) in living tissue and the blood oxygenation degree indicating the ratio. is there.

【0027】まず、本発明の生体組織血液量測定装置の
構成を説明する。本発明の生体組織血液量測定装置1
は、図1に示すように、生体組織(以下、組織という)
8に対し3種類以上の互いに波長の近い近赤外線の光源
11,12,13を所定の強度で直接照射する測定光出
力部と、出力された光源11,12,13の測定光(以
下、測定光a,b,cとする)が組織8を通過した透過
散乱光の強度を2点の測定点で検出する検出部7a,7
bと、出力された測定光a,b,cと検出された透過散
乱光の強度から得られる組織8中の全赤血球数に対する
光吸収量に基づき組織8中の酸素化赤血球量(または酸
素化ヘモグロビン量)、脱酸素化赤血球量(または脱酸
素化ヘモグロビン量)と全血液の酸素化度合を演算する
演算部(演算処理回路)17a,17bと、2点の測定
点から、前記演算した各測定値に対し組織8自体の光吸
収度合より生じる誤差を補正する補正部(差分演算)2
0と、を備えている。
First, the structure of the biological tissue blood volume measuring apparatus of the present invention will be described. Biological tissue blood volume measuring device 1 of the present invention
Is a living tissue (hereinafter referred to as a tissue) as shown in FIG.
8 measuring light output section for directly irradiating three or more types of near infrared light sources 11, 12, 13 having wavelengths close to each other at a predetermined intensity, and measuring light output from the light sources 11, 12, 13 (hereinafter referred to as measurement light). Lights a, b, and c) detect the intensities of the transmitted scattered light that has passed through the tissue 8 at two measurement points.
b, the amount of oxygenated red blood cells in the tissue 8 (or oxygenation) based on the amount of light absorption with respect to the total number of red blood cells in the tissue 8 obtained from the intensity of the output measurement light a, b, c and the detected transmitted scattered light. The amount of hemoglobin), the amount of deoxygenated red blood cells (or the amount of deoxygenated hemoglobin), and the arithmetic units (arithmetic processing circuits) 17a and 17b for arithmetically operating the degree of oxygenation of whole blood. Correction unit (difference calculation) 2 for correcting an error caused by the light absorption degree of the tissue 8 itself with respect to the measured value
It has 0 and.

【0028】そして、この測定光出力部は、光源11,
12,13と、光合波器15と、光コネクタ2と、光フ
ァイバー4と、プローブ6とを備えている。
The measuring light output section is provided with a light source 11,
12 and 13, an optical multiplexer 15, an optical connector 2, an optical fiber 4, and a probe 6.

【0029】この中で、光源11,12,13は、3種
類の波長が異なるが近接する3つの単光色を発する発光
素子と、光を効率よく光ファイバー等に導光するための
集光器と、から構成されている。この発光素子は、例え
ば、3種類の狭い波長域の可視光または近赤外光である
レーザー光(測定光a,b,c)を発振するレーザダイ
オード(Laser Diode)である。また、光源11,1
2,13は、光合波器15と接続し、出力された測定光
a,b,cは集光器にて集光されて光合波器15へ送ら
れる。更に、光源11,12,13には、駆動回路19
より駆動電流が供給されている。
Among these, the light sources 11, 12, and 13 are light-emitting elements that emit three single-color lights that are different in three types of wavelengths but are close to each other, and a condenser for efficiently guiding light to an optical fiber or the like. It consists of and. This light emitting element is, for example, a laser diode (Laser Diode) that oscillates laser light (measurement light a, b, c) that is visible light or near infrared light in three types of narrow wavelength bands. Also, the light sources 11, 1
Reference numerals 2 and 13 are connected to the optical multiplexer 15, and the output measurement lights a, b, and c are condensed by the condenser and sent to the optical multiplexer 15. Further, the light source 11, 12, 13 includes a drive circuit 19
More drive current is being supplied.

【0030】そして、この光合波器15は、光源11,
12,13のそれぞれと接続するとともに、光コネクタ
2と接続し、集光された測定光a,b,cを光コネクタ
2を介して1本、または複数本の光ファイバー4に導光
する。
The optical multiplexer 15 includes a light source 11,
In addition to being connected to each of 12 and 13, it is also connected to the optical connector 2, and the condensed measurement light a, b, c is guided to one or a plurality of optical fibers 4 via the optical connector 2.

【0031】なお、各光源は、タイミング回路18が指
定する時分割で時間をずらして供給される駆動回路19
の駆動電流により発光され、光コネクタ2を介して光フ
ァイバー4に導光する。
It should be noted that each light source is driven by a driving circuit 19 which is supplied with a time shift specified by the timing circuit 18.
The light is emitted by the drive current of and is guided to the optical fiber 4 through the optical connector 2.

【0032】そして、このタイミング回路18は、図2
(a)のパルス図に示すように、所定時間毎にパルスP
1,P2,P3,P4,…を刻んでいる。また、タイミ
ング回路18は、駆動回路19に対し、パルスP1の時
に測定光aを発光させるように通知する(図2(b)参
照)。同様に、タイミング回路18は、駆動回路19に
対し、パルスP2の時に測定光bを(図2(c)参
照)、パルスP3の時に測定光cを(図2(d)参
照)、発光させるように通知する。
The timing circuit 18 is shown in FIG.
As shown in the pulse diagram of (a), a pulse P is generated every predetermined time.
1, P2, P3, P4, ... are engraved. In addition, the timing circuit 18 notifies the drive circuit 19 to emit the measurement light a at the pulse P1 (see FIG. 2B). Similarly, the timing circuit 18 causes the drive circuit 19 to emit the measurement light b during the pulse P2 (see FIG. 2C) and the measurement light c during the pulse P3 (see FIG. 2D). To notify you.

【0033】なお、組織8に導光されて透過、散乱した
測定光a,b,cは、タイミング回路18が指定する時
分割で時間をずらし、後述する光検出器7a,7bによ
り検出される。
The measuring lights a, b and c which are guided to the tissue 8 and transmitted and scattered are time-divided by the timing circuit 18 and are detected by the photodetectors 7a and 7b which will be described later. .

【0034】そして、この光コネクタ2は、光ファイバ
ー4と着脱自在に接続し、測定光a,b,cが装置本体
1から光ファイバー4を介して外部(組織8)へ出力す
るためのコネクタである。
The optical connector 2 is a connector that is detachably connected to the optical fiber 4 and outputs the measurement light a, b, c from the apparatus body 1 to the outside (tissue 8) via the optical fiber 4. .

【0035】また、この光ファイバー4は、例えば石英
系の光ファイバーであり、一端が光コネクタ2と着脱自
在に接続し、他端がプローブ6と接続している。また、
光ファイバー4は、波長の異なる3種類の測定光a,
b,cをプローブ6を通して組織8に照射する。
The optical fiber 4 is, for example, a quartz optical fiber, one end of which is detachably connected to the optical connector 2 and the other end of which is connected to the probe 6. Also,
The optical fiber 4 is composed of three types of measuring light a with different wavelengths a,
The tissue 8 is irradiated with b and c through the probe 6.

【0036】更に、このプローブ6は、組織8上のある
点に密着して配置され、光ファイバー4より照射された
測定光a,b,cを組織8に出力する。
Further, the probe 6 is placed in close contact with a certain point on the tissue 8 and outputs the measurement light a, b, c emitted from the optical fiber 4 to the tissue 8.

【0037】そして、出力された測定光a,b,cは、
組織8内の酸素化赤血球(または酸素化ヘモグロビン)
や脱酸素化赤血球(または脱酸素化ヘモグロビン)やそ
の他の体液を通過して検出部7a,7bにより検出され
る。
Then, the output measurement lights a, b, c are
Oxygenated red blood cells (or oxygenated hemoglobin) in tissue 8
And deoxygenated red blood cells (or deoxygenated hemoglobin) and other body fluids, and are detected by the detection units 7a and 7b.

【0038】そして、この検出部7a,7bは、それぞ
れ電線5a,5bと、電気的コネクタ3a,3bと、光
増幅器(アンプ)16a,16bと接続している。
The detectors 7a and 7b are connected to the electric wires 5a and 5b, the electrical connectors 3a and 3b, and the optical amplifiers (amplifiers) 16a and 16b, respectively.

【0039】この中で、光検出器7aは、例えば、フォ
トダイオードであり、組織8より測定光(すなわち透過
光)を受光し、受光した透過光の強度を検出する装置で
あり、光ファイバー4の光照射点(プローブ6の位置)
から所定距離L1(数cm程度)離れた点に配設されて
いる。また、光検出器7bも、光検出器7aと同様に受
光した透過光の強度を検出する装置であり、プローブ6
の位置から所定距離L2(数cm:L2>L1)程度離
れた点に配設されている。そして、この光検出器7a,
7bは、検出した透過光の強度情報を電線5を介して装
置本体1に通知する。
Among them, the photodetector 7a is, for example, a photodiode, which is an apparatus for receiving the measurement light (that is, the transmitted light) from the tissue 8 and detecting the intensity of the received transmitted light. Light irradiation point (probe 6 position)
It is arranged at a point separated by a predetermined distance L1 (about several cm) from. Further, the photodetector 7b is also a device for detecting the intensity of the transmitted light received similarly to the photodetector 7a, and the probe 6
Is disposed at a point about a predetermined distance L2 (several cm: L2> L1) from the position. Then, this photodetector 7a,
7b notifies the apparatus main body 1 of the detected intensity information of the transmitted light via the electric wire 5.

【0040】この電線5a,5bは、例えばシールド線
であり、一端が装置本体1側にある電気的コネクタ3
a,3bとそれぞれ着脱自在に接続し、他端が光検出器
7a,7bと接続している。
The electric wires 5a and 5b are, for example, shield wires, and one end of the electric connector 3 is on the apparatus main body 1 side.
a and 3b are detachably connected, and the other ends are connected to photodetectors 7a and 7b.

【0041】この電気的コネクタ3a,3bは、電線5
a,5bとそれぞれ着脱自在に接続し、また、この電気
的コネクタ3a,3bは、増幅器16a,16bとそれ
ぞれ接続している。
The electrical connectors 3a and 3b are connected to the electric wire 5
a and 5b are detachably connected, and the electrical connectors 3a and 3b are connected to amplifiers 16a and 16b, respectively.

【0042】この増幅器16a,16bは、電気的コネ
クタ3a,3bより導入された3種類の透過光の強度情
報を増幅する装置である。また、この増幅器16a,1
6bは演算部(演算処理回路)17a,17bとそれぞ
れ接続している。
The amplifiers 16a and 16b are devices for amplifying the intensity information of the three types of transmitted light introduced from the electrical connectors 3a and 3b. Also, the amplifiers 16a, 1
Reference numeral 6b is connected to the arithmetic units (arithmetic processing circuits) 17a and 17b, respectively.

【0043】そして、この演算部17a,17bは、タ
イミング回路18と接続し、タイミング回路18が指定
する時分割に基づいて、検出された透過光の強度情報を
識別し、識別した組織8中の酸素化赤血球量「V1
L」、脱酸素化赤血球量「V2・L」及び酸素化度合R
を演算する。
The operation units 17a and 17b are connected to the timing circuit 18, identify the intensity information of the detected transmitted light based on the time division designated by the timing circuit 18, and identify the identified tissue 8 in the tissue 8. Oxygenated red blood cell volume "V 1
L ”, deoxygenated red blood cell volume“ V 2 · L ”and oxygenation degree R
Is calculated.

【0044】また、補正部(差分演算)20は、酸素化
度合演算部17a,17bと接続し、酸素化度合演算部
17a,17bが演算した2点の測定点からの値の差分
を求め、各測定値に対し組織8自体の光吸収度合より生
じる誤差を補正する。
Further, the correction section (difference calculation) 20 is connected to the oxygenation degree calculation sections 17a and 17b, and obtains a difference in value from the two measurement points calculated by the oxygenation degree calculation sections 17a and 17b. An error caused by the degree of light absorption of the tissue 8 itself is corrected for each measured value.

【0045】[酸素化度合演算部(演算処理回路)の説
明]次に、この演算処理回路17a,17bの演算手順
を説明する。なお、光検出器7a,7bで受光される透
過光の強度(強度情報)は、組織8中の血液による吸収
のみでなく、体液を含めた組織8自体による散乱と吸収
によって減衰(変化)する。すなわち、これら組織8を
透過してきた測定光の強度は、ブーゲ−ランバート−ベ
ールの法則(Bouguer-Lambert-Beer law)によれば、組織
8自体による散乱と吸収によって、その通過距離に関し
て指数関数的に減少する。従って、単波長の透過光の強
度Iは、一般的に[数式1]で表すことができる。
[Explanation of Oxygenation Degree Calculation Unit (Calculation Processing Circuit)] Next, the calculation procedure of the calculation processing circuits 17a and 17b will be described. The intensity (intensity information) of the transmitted light received by the photodetectors 7a and 7b is attenuated (changed) by not only absorption by blood in the tissue 8 but also scattering and absorption by the tissue 8 itself including body fluid. . That is, according to the Bouguer-Lambert-Beer law, the intensity of the measurement light transmitted through the tissues 8 is exponential with respect to the passage distance due to scattering and absorption by the tissues 8 themselves. Decrease to. Therefore, the intensity I of the transmitted light of a single wavelength can be generally expressed by [Formula 1].

【0046】[0046]

【数4】 [Equation 4]

【0047】なお、[数式1]において、Iは光検出器
7で検出された受光(透過光)強度を示し、ηは光シス
テムに関わる係数を示し、I0 は照射した測定光強度を
示し、exp( )は指数関数を意味する。
In Equation 1, I represents the intensity of received light (transmitted light) detected by the photodetector 7, η is a coefficient relating to the optical system, and I 0 is the intensity of the measured light emitted. , Exp () means exponential function.

【0048】また、αは単位体積、単位光路長当たりの
酸素化赤血球の吸収係数を示し、V 1 は単位体積当た
りの酸素化赤血球の量を示し、βは単位体積、単位光路
長当たりの脱酸素化赤血球の吸収係数を示し、V2 は単
位体積当たりの脱酸素化赤血球の量を示し、μは単位長
当たりの組織の、散乱係数を示し、Lは照射点と受光点
間の距離(光路長)を示す。
Further, α is per unit volume and unit optical path length
Shows the absorption coefficient of oxygenated red blood cells, V 1Is the unit volume
Is the amount of oxygenated red blood cells, β is the unit volume, unit optical path
Shows the absorption coefficient of deoxygenated red blood cells per length, V2 Is simply
Indicates the amount of deoxygenated red blood cells per unit volume, μ is the unit length
Shows the scattering coefficient of the tissue per hit, L is the irradiation point and the light receiving point
Indicates the distance (optical path length) between them.

【0049】ここで、[数式1]は各測定光毎に得られ
る式であり、各測定光波長におけるα、βを代入して酸
素化赤血球量や脱酸素化赤血球量を求めている。各測定
光波長のα、βの値は既知である。従って、未知数はV
1,V2とμの3種類であるために3つの方程式が必要と
なる。そこで、測定光は通常3種類以上となる。また、
μは各測定光波長が互いに近接しておれば、同じ値とし
て近似できる。
Here, [Equation 1] is an equation obtained for each measurement light, and α and β at each measurement light wavelength are substituted to obtain the oxygenated red blood cell amount and the deoxygenated red blood cell amount. The values of α and β of each measurement light wavelength are known. Therefore, the unknown is V
Three equations are necessary because there are three types, 1 , V 2 and μ. Therefore, there are usually three or more types of measuring light. Also,
If the measurement light wavelengths are close to each other, μ can be approximated as the same value.

【0050】演算処理回路17a,17bは、組織8中
の酸素化赤血球量、脱酸素化赤血球量および血液の酸素
化度合(酸素化赤血球量V1 と脱酸素化赤血球量V2
比率で、V1 /(V1+V2)として求められる)を求め
るものである。
The arithmetic processing circuits 17a and 17b are used to calculate the amount of oxygenated red blood cells in the tissue 8, the amount of deoxygenated red blood cells, and the degree of oxygenation of blood (the ratio of the amount V 1 of oxygenated red blood cells to the amount V 2 of deoxygenated red blood cells, V 1 / (V 1 + V 2 )).

【0051】そして、[数式1]において、酸素化赤血
球の吸収係数α1 及び脱酸素化赤血球の吸収係数α2
は、図8の波長特性図に示すように、分光光度計等で測
定可能な数値であるが、散乱係数と吸収係数の和μは、
未知数である。しかしながら、散乱係数及び吸収係数の
波長特性は、狭い波長領域内(特に近赤外領域)では、
直線性があることが知られている。
Then, in [Equation 1], the absorption coefficient α 1 of oxygenated red blood cells and the absorption coefficient α 2 of deoxygenated red blood cells
Is a numerical value that can be measured by a spectrophotometer or the like as shown in the wavelength characteristic diagram of FIG. 8, and the sum μ of the scattering coefficient and the absorption coefficient is
It is an unknown number. However, the wavelength characteristics of the scattering coefficient and the absorption coefficient are within a narrow wavelength range (particularly in the near infrared range).
It is known to have linearity.

【0052】次に、3種類の測定光によって得られた受
光量から連立方程式を解くと、次の[数式2]と[数式
3]が得られる。
Next, when the simultaneous equations are solved from the received light amounts obtained by the three types of measurement light, the following [Equation 2] and [Equation 3] are obtained.

【0053】[0053]

【数5】 [Equation 5]

【数6】 [Equation 6]

【0054】そこで、光路長Lの値を[数式2]と[数
式3]に代入することで、酸素化赤血球量や脱酸素化赤
血球量が求められる。
Therefore, by substituting the value of the optical path length L into [Equation 2] and [Equation 3], the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells can be obtained.

【0055】なお、[数式2]及び[数式3]におい
て、I1,I2およびI3 は光検出器7で検出された測
定光1,2,および3の受光(透過光)強度を示し、I
10,I 20およびI30は照射した測定光1,2,および3
の照射光強度を示し、Lnは自然対数を示し、A,B,
C及びDはα1,α2,α3 およびβ1,β2,β3 で表
される係数を意味する。
It should be noted that in [Equation 2] and [Equation 3],
I1, I2And I3Is measured by the photodetector 7.
Indicates the intensity of received light (transmitted light) of constant light 1, 2, and 3, and I
Ten, I 20And I30Is the measuring light 1, 2, and 3 which is irradiated
Of the irradiation light, Ln represents a natural logarithm, A, B,
C and D are α1, Α2, Α3 And β1, Β2, Β3Table
Means the coefficient to be applied.

【0056】そして、組織8自体が皮膚のメラニン色素
などによって光の吸収度合が波長によって異なる場合の
光の吸収を考慮すると、[数式1]は[数式4]のよう
に表される。
Then, considering the light absorption when the tissue 8 itself has a different light absorption degree due to the melanin pigment of the skin or the like, [Equation 1] is expressed as [Equation 4].

【0057】[0057]

【数7】 [Equation 7]

【0058】なお、[数式4]において、γは組織自体
による吸収係数である。よって、[数式2]及び[数式
3]は[数式5]及び[数式6]のように表される。
In Equation 4, γ is the absorption coefficient of the tissue itself. Therefore, [Equation 2] and [Equation 3] are expressed as [Equation 5] and [Equation 6].

【0059】[0059]

【数8】 [Equation 8]

【数9】 [Equation 9]

【0060】なお、[数式5]及び[数式6]におい
て、E及びFは測定光1,2及び3の各々の吸収係数γ
1,γ2およびγ3 の関数で、[数式7]及び[数式8]
のように表される。
In [Equation 5] and [Equation 6], E and F are absorption coefficients γ of the measurement lights 1, 2 and 3, respectively.
[Equation 7] and [Equation 8] are functions of 1 , γ 2 and γ 3 .
It is expressed as.

【0061】[0061]

【数10】 [Equation 10]

【数11】 [Equation 11]

【0062】なお、[数式7]及び[数式8]におい
て、Γn=Ln(γn)を示す。
In Equations 7 and 8, Γ n = Ln (γ n ) is shown.

【0063】この関数Eおよび関数Fが組織8自体の吸
収度合により生じる誤差(オフセット分)として測定値
に影響を及ぼす。
The functions E and F affect the measured value as an error (offset amount) caused by the degree of absorption of the tissue 8 itself.

【0064】例えば、光照射点(プローブ6)と光検出
器間の距離Lを変化させて生体組織を測定したときの、
距離Lと酸素化赤血球量「V1・L」及び脱酸素化赤血
球量「V2・L」の典型的な関係を図3に示す。
For example, when measuring the living tissue by changing the distance L between the light irradiation point (probe 6) and the photodetector,
FIG. 3 shows a typical relationship between the distance L and the oxygenated red blood cell amount "V 1 .L" and the deoxygenated red blood cell amount "V 2 .L".

【0065】図3によれば、Lが大きくなれば、測定対
象体積が大きくなるので、多くの血液によって光が吸収
される。ここで、「L=0」のときには血液による吸収
がないため、本来ならば「V1・L」または「V2・L」
の回帰直線は零点と交差するはずである。しかし、上記
γの値が各波長によって異なっているので、関数E及び
関数Fが誤差(オフセット分)の原因と関わっていると
考えられる。
According to FIG. 3, the larger L becomes, the larger the volume to be measured becomes, so that light is absorbed by a large amount of blood. Here, when “L = 0”, since there is no absorption by blood, “V 1 · L” or “V 2 · L” should be used.
The regression line of should cross the zero. However, since the value of γ differs for each wavelength, it is considered that the functions E and F are related to the cause of the error (offset amount).

【0066】例えば、検出する血液量が多いとき、すな
わち「L」が大きいときにはこのオフセット分は相対的
に小さいが、「L」が小さいときには実際の血液量の値
よりも大きくなってしまう。従って、小さい体積中の酸
素化赤血球量と脱酸素化赤血球量を測定しようとする場
合には、この誤差(オフセット分)を消去しないと正し
い値が得られない。
For example, when the blood volume to be detected is large, that is, when "L" is large, this offset amount is relatively small, but when "L" is small, it becomes larger than the actual blood volume value. Therefore, when trying to measure the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells in a small volume, correct values cannot be obtained unless this error (offset amount) is deleted.

【0067】そこで、更に光吸収度合による誤差(オフ
セット分)の発生のメカニズムを説明し、次に、補正部
(差分演算)20の演算手順を説明する。従来の技術で
述べた図6に示す装置で指先を測定すると、図7に示す
照射点と測定点間距離Lと血液量VLの関係図が得られ
る。
Therefore, the mechanism of generating an error (offset amount) due to the degree of light absorption will be further described, and then the calculation procedure of the correction section (difference calculation) 20 will be described. When the fingertip is measured by the device shown in FIG. 6 described in the related art, the relationship diagram between the irradiation point and the distance L between the measurement points and the blood volume VL shown in FIG. 7 is obtained.

【0068】なお、図7において、使用した測定光は6
35nm,655nmおよび690nmのレーザーダイ
オードである。また、[数式5]及び[数式6]に示す
A,B,CおよびDの値は、上記レーザーダイオードを
用いた測定光のときの赤血球の吸収係数から各々「A=
-6.48」,「B=2.58」,「C=0.19」および「D=-0.
77」とした。
In FIG. 7, the measuring light used is 6
Laser diodes of 35 nm, 655 nm and 690 nm. Further, the values of A, B, C, and D shown in [Equation 5] and [Equation 6] are each "A = B" from the absorption coefficient of erythrocytes in the measurement light using the laser diode.
-6.48 "," B = 2.58 "," C = 0.19 "and" D = -0.
77 ”.

【0069】図7に示すように、酸素化赤血球量「V1
・L」及び脱酸素化赤血球量「V2・L」は照射点と測
定点間距離「L」に比例していることが確認できる。
As shown in FIG. 7, the amount of oxygenated red blood cells "V 1
It can be confirmed that “L” and the amount of deoxygenated red blood cells “V 2 · L” are proportional to the distance “L” between the irradiation point and the measurement point.

【0070】このことは、単位面積当たりの赤血球量V
Lは、照射点と測定点間距離Lがわずかな違いであるな
らば、照射点と測定点間距離Lに依存せずにほぼ一定で
あることを示している。
This means that the red blood cell amount V per unit area is
L indicates that if the distance L between the irradiation point and the measurement point is a slight difference, it is almost constant without depending on the distance L between the irradiation point and the measurement point.

【0071】また、酸素化赤血球量「V1・L」と脱酸
素化赤血球量「V2・L」は共に「L=0」のときにオ
フセット分を有しており、特に酸素化赤血球量を示す
「V1・L」のオフセット分は測定値に対して非常に大
きいことがわかる。なお、酸素化赤血球量「V1・L」
のオフセット分が脱酸素化赤血球量「V2・L」のオフ
セット分に比較して大きい理由は、[数式7]と[数式
8]で表されるように、A,B,CおよびDの係数の差
によるためである。
The oxygenated red blood cell amount "V 1 .L" and the deoxygenated red blood cell amount "V 2 .L" both have an offset when "L = 0". It can be seen that the offset amount of “V 1 · L” indicating is extremely large with respect to the measured value. The amount of oxygenated red blood cells "V 1 L"
The reason why the offset amount of A is larger than the offset amount of the deoxygenated red blood cell amount “V 2 · L” is that A, B, C, and D are as shown in [Equation 7] and [Equation 8]. This is because of the difference in the coefficients.

【0072】このように、測定点が1点のみの従来の測
定方法では正確な血液量を求めることができない。
As described above, an accurate blood volume cannot be obtained by the conventional measuring method having only one measuring point.

【0073】[補正部(差分演算)の説明]そこで、本
実施の形態では、2個の光検出器7a,7bを光照射点
6から異なる場所L1,L2に設置している。そして、
演算処理回路17a,17bはそれぞれの検出点で受光
した光強度から酸素化赤血球量「V1・L」と脱酸素化
赤血球量「V2・L」を[数式5]と[数式6]によっ
て求めている。なお、演算処理回路17a,17bで求
めた酸素化赤血球量「V1・L」と脱酸素化赤血球量
「V2・L」はオフセット分を含んでいる。
[Description of Correction Unit (Differential Calculation)] Therefore, in the present embodiment, two photodetectors 7a and 7b are installed at different locations L1 and L2 from the light irradiation point 6. And
The arithmetic processing circuits 17a and 17b calculate the oxygenated red blood cell amount "V 1 .L" and the deoxygenated red blood cell amount "V 2 .L" from the light intensities received at the respective detection points by [Equation 5] and [Equation 6]. Looking for. The oxygenated red blood cell amount "V 1 .L" and the deoxygenated red blood cell amount "V 2 .L" obtained by the arithmetic processing circuits 17a and 17b include offsets.

【0074】補正部(差分演算)20は、その差分を計
算することで、組織8自体の吸収係数が不明でも、オフ
セット分を消去したより正確な酸素化赤血球量「V1
L」と脱酸素化赤血球量「V2・L」を得るものであ
る。なお、光照射点6からの光検出点間距離L1,L2
既知、または測定可能であるために、酸素化赤血球量
「V1・L」と脱酸素化赤血球量「V2・L」を距離Lで
規格化することが可能である。
The correction unit (difference calculation) 20 calculates the difference so that even if the absorption coefficient of the tissue 8 itself is unknown, the more accurate oxygenated red blood cell amount “V 1 ·
L "and the amount of deoxygenated red blood cells" V 2 .L ". Since the distances L 1 and L 2 between the light detection points from the light irradiation point 6 are known or measurable, the oxygenated red blood cell amount “V 1 · L” and the deoxygenated red blood cell amount “V 2 · L” are measured. Can be standardized by the distance L.

【0075】すなわち、差分演算20処理の場合、光照
射点6からL離れた測定点1での受光信号から演算して
得られた酸素化赤血球量V1・L1は[数式9]として求
められ、同様にL2離れた測定点2での受光信号から演
算して得られた酸素化赤血球量V1・L2は[数式10]
で求められる。
That is, in the case of the difference calculation 20 process, the oxygenated red blood cell amount V 1 .L 1 obtained by calculation from the received light signal at the measurement point 1 which is L away from the light irradiation point 6 is obtained as [Equation 9]. Similarly, the oxygenated red blood cell amount V 1 · L 2 obtained by calculation from the received light signal at the measurement point 2 separated by L 2 is [Equation 10]
Required by.

【0076】[0076]

【数12】 [Equation 12]

【0077】[0077]

【数13】 ここで、ILmnは、測定点mにおける測定光Inの受光強
度を示す。
[Equation 13] Here, I Lmn indicates the received light intensity of the measurement light I n at the measurement point m.

【0078】上記[数式9]と[数式10]の減算から
酸素化赤血球量がV1・(L2−L1) として求めら
れ、この値はオフセット分であるEを含まない。同様に
して脱酸素化赤血球量V2・(L2−L1)も求められ
る。
The amount of oxygenated red blood cells is obtained as V 1 (L 2 −L 1 ) from the subtraction of [Equation 9] and [Equation 10], and this value does not include the offset E. Similarly, the amount of deoxygenated red blood cells V 2 · (L 2 −L 1 ) is also obtained.

【0079】また、全血液量の酸素化度合(酸素飽和
度)Rは[数式11]より得られる。
The oxygenation degree R of the total blood volume (oxygen saturation) R is obtained from [Equation 11].

【0080】[0080]

【数14】 [Equation 14]

【0081】図4に測定点1と2が光照射点6から各々
1とL2離れた2箇所の測定点の場合の酸素化赤血球量
と脱酸素化赤血球量を求める概念図を示す。
FIG. 4 shows a conceptual diagram for obtaining the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells when the measurement points 1 and 2 are two measurement points separated from the light irradiation point 6 by L 1 and L 2, respectively.

【0082】図5に本発明の実施例を示す。この図5
は、L1は光照射点6から1mmで、L2を光照射点6から
2mm,4mm,6mmおよび8mmの位置に移動させて、(L
2−L1)に対する酸素化赤血球量と脱酸素化赤血球量の
特性を調べた結果を示している。
FIG. 5 shows an embodiment of the present invention. This Figure 5
, L 1 is 1 mm from the light irradiation point 6 and L 2 is moved from the light irradiation point 6 to positions of 2 mm, 4 mm, 6 mm and 8 mm, and (L
2 shows the results of examining the characteristics of the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells with respect to 2- L 1 ).

【0083】なお、図5において、使用した測定光は6
35nm,655nmおよび690nmのレーザーダイ
オードである。また、[数式5]及び[数式6]に示す
A,B,CおよびDの値は、上記レーザーダイオードを
用いた測定光のときの血液の吸収係数から各々「A=-
6.48」,「B=2.58」,「C=0.19」および「D=-0.7
7」とした。
In FIG. 5, the measuring light used is 6
Laser diodes of 35 nm, 655 nm and 690 nm. Further, the values of A, B, C and D shown in [Equation 5] and [Equation 6] are respectively "A =-" from the absorption coefficient of blood when measuring light using the laser diode.
6.48 ”,“ B = 2.58 ”,“ C = 0.19 ”and“ D = -0.7
7 ”.

【0084】従来の図7と比較して、本発明の図5では
L=0のときのオフセット分がほぼ0(ゼロ)付近であ
ることが示されている。
Compared to the conventional FIG. 7, FIG. 5 of the present invention shows that the offset component when L = 0 is approximately 0 (zero).

【0085】また、2本の回帰直線の増加率は図7の各
値とほぼ同じであり、増加率が単位体積当たりの酸素化
赤血球量と脱酸素化赤血球量に相当する。
The rate of increase of the two regression lines is almost the same as the values in FIG. 7, and the rate of increase corresponds to the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells per unit volume.

【0086】[本実施の形態の生体組織血液量測定装置
の作用]次に、本実施の形態の生体組織血液量測定装置
の作用を説明する。なお、演算処理回路17a,17b
が演算するに当たって必要とする所定の数値、例えば、
測定光の強度や、距離L1,L2は、予め設定されてい
るものとする。また、光ファイバー4は光コネクタ2を
介して装置本体1に接続されているものとし、電線5
a,5bは電気的コネクタ3a,3bを介して装置本体
1に接続されているものとする。
[Operation of Living Tissue Blood Volume Measuring Apparatus of this Embodiment] Next, the operation of the living tissue blood volume measuring apparatus of this embodiment will be described. The arithmetic processing circuits 17a and 17b
Is a predetermined numerical value required to calculate, for example,
The intensity of the measuring light and the distances L1 and L2 are set in advance. Further, the optical fiber 4 is assumed to be connected to the apparatus main body 1 via the optical connector 2, and the electric wire 5
It is assumed that a and 5b are connected to the apparatus main body 1 via electrical connectors 3a and 3b.

【0087】本実施の形態の生体組織血液量測定装置1
の使用者(以下、使用者という)は、光ファイバー4の
端部に設けられたプローブ6を測定対象の組織8上面に
密着配置する。また、使用者は、プローブ6の密着位置
(光照射点)から距離L1の位置に光検出器7aを設定
し、また光照射点6から距離L2 の位置に光検出器7
bを設置する。
Living tissue blood volume measuring apparatus 1 of the present embodiment
The user (hereinafter, referred to as “user”) closely arranges the probe 6 provided at the end of the optical fiber 4 on the upper surface of the tissue 8 to be measured. Further, the user sets the photodetector 7a at a position at a distance L 1 from the close contact position (light irradiation point) of the probe 6, and at the position at a distance L 2 from the light irradiation point 6 to the photodetector 7a.
Install b.

【0088】次に、使用者は、装置本体1を起動させる
と、タイミング回路18のパルス波のタイミングに基づ
き駆動回路19より駆動電流が光源11,12,13に
時分割で供給される。すると、測定光a,b,cが時分
割で光合波器15に出力され、順次光ファイバー4に導
光される。
Next, when the user activates the apparatus main body 1, a drive current is supplied from the drive circuit 19 to the light sources 11, 12 and 13 in a time division manner based on the timing of the pulse wave of the timing circuit 18. Then, the measurement lights a, b, and c are time-divisionally output to the optical multiplexer 15 and sequentially guided to the optical fiber 4.

【0089】導光された測定光a,b,cは、プローブ
6から組織8内に出力され、組織8内の血液を含む体液
を通過する際に散乱と吸収によって減衰する。
The guided measurement lights a, b and c are output from the probe 6 into the tissue 8 and attenuated by scattering and absorption when passing through the body fluid containing blood in the tissue 8.

【0090】次に、光検出器7a,7bは、減衰した測
定光a,b,cである透過光を順次受光して透過光の強
度を検出する。そして、光検出器7a,7bは、電線5
a,5b及び電気的コネクタ3a,3bを介して、検出
値を測定光毎に強度情報として増幅器16a,16bに
通知する。
Next, the photodetectors 7a and 7b sequentially receive the transmitted light which is the attenuated measuring light a, b and c and detect the intensity of the transmitted light. The photodetectors 7a and 7b are connected to the electric wire 5
The detected values are notified to the amplifiers 16a and 16b as intensity information for each measurement light via a and 5b and the electrical connectors 3a and 3b.

【0091】増幅器16a,16bは、通知された測定
光毎の強度情報を増幅して演算処理回路17a,17b
に通知し、演算処理回路17a,17bは、タイミング
回路18のパルス波のタイミングに基づき、通知された
測定光a,b,cの強度情報を識別するとともに、前述
の演算手順に従って、組織8中の酸素化赤血球量「V 1
・L」、脱酸素化赤血球量「V2・L」及び全血液量に
対する酸素化度合Rをそれぞれの測定点毎に演算する。
The amplifiers 16a and 16b receive the notified measurement.
Amplification of intensity information for each light and arithmetic processing circuits 17a and 17b
And the arithmetic processing circuits 17a and 17b notify the timing
Notified based on the timing of the pulse wave of the circuit 18
In addition to identifying the intensity information of the measurement lights a, b and c,
Oxygenated red blood cell amount in the tissue 8 "V 1
・ L ”, deoxygenated red blood cell volume“ V ”2・ For L and total blood volume
The oxygenation degree R corresponding to each measurement point is calculated.

【0092】次に、補正部(差分演算)20は、前述の
手順に基づき酸素化度合演算部17a,17bが演算し
た2点の測定点からの値の差分[酸素化赤血球量V1
(L2−L1)及び脱酸素化赤血球量V2・(L2
1)]を求めて関数Eおよび関数Fを排除し、組織8
自体の光吸収度合より生じる誤差を補正してより正確な
酸素化赤血球量、または脱酸素化赤血球量を求める。ま
た、求めた差分[酸素化赤血球量V1・(L2−L1)及
び脱酸素化赤血球量V2・(L2−L1)]に基づき全血
液量の酸素化度合(酸素飽和度)Rを算出する。
Next, the correction unit (difference calculation) 20 calculates the difference between the values from the two measurement points calculated by the oxygenation degree calculation units 17a and 17b based on the above-mentioned procedure [oxygenated red blood cell amount V 1.
(L 2 −L 1 ) and the amount of deoxygenated red blood cells V 2 · (L 2
L 1 )], the functions E and F are excluded, and the tissue 8
A more accurate oxygenated red blood cell amount or deoxygenated red blood cell amount is obtained by correcting an error caused by the light absorption degree of itself. Further, based on the obtained difference [oxygenated red blood cell amount V 1 (L 2 −L 1 ) and deoxygenated red blood cell amount V 2 (L 2 −L 1 )], the oxygenation degree of the total blood volume (oxygen saturation ) Calculate R.

【0093】そして、算出された酸素化赤血球量V1
(L2−L1)、脱酸素化赤血球量V2・(L2−L1)及
び全血液量の酸素化度合(酸素飽和度)Rは、差分演算
20から図示しない外部表示手段に出力されて表示され
る。
Then, the calculated oxygenated red blood cell amount V 1 ·
(L 2 −L 1 ), deoxygenated red blood cell volume V 2 · (L 2 −L 1 ) and oxygenation degree (oxygen saturation) R of the total blood volume are output from the difference calculation 20 to an external display means (not shown). Is displayed.

【0094】なお、上記実施の形態では、測定点が2点
の場合で説明したが、測定点が3個所以上の場合は、回
帰式を求めてその傾きから酸素化赤血球量と脱酸素化赤
血球量を得ることができる。すなわち、測定点L1,L
2〜Lnで酸素化赤血球量が各々、V1・L2〜V1・
Lnで求められると、一般的に一次回帰直線がV・L=
a+b・Lの形で得られる。
In the above embodiment, the case where the number of measurement points is 2 has been described. However, when the number of measurement points is 3 or more, a regression equation is obtained and the oxygenated red blood cell amount and deoxygenated red blood cell are calculated from the slopes thereof. You can get the quantity. That is, the measurement points L1 and L
2 to Ln and the amount of oxygenated red blood cells is V1 · L2 to V1 ·
When calculated by Ln, a linear regression line is generally V · L =
Obtained in the form a + b · L.

【0095】ここで切片aは、[数式12]として求め
られる。
Here, the intercept a is obtained as [Equation 12].

【数15】 [Equation 15]

【0096】また、係数bは、[数式13]として求め
られる。
Further, the coefficient b is obtained as [Equation 13].

【数16】 [Equation 16]

【0097】ここで、Σ(L,VL)はLと測定値VL
の積和であり、Σ(L)は、Lの総和、Σ(V・L)は
測定値V・Lの総和である。ここで係数bが回帰直線の
傾きであり、本発明の単位体積当たりの酸素化赤血球量
V1、または脱酸素化赤血球量V2に相当する。
Here, Σ (L, VL) is L and the measured value VL
Σ (L) is the sum of L, and Σ (V · L) is the sum of the measured values V · L. Here, the coefficient b is the slope of the regression line, and corresponds to the oxygenated red blood cell amount V1 or the deoxygenated red blood cell amount V2 per unit volume of the present invention.

【0098】また、上記実施の形態において酸素化赤血
球量を求める式をベールの法則で示しているが、拡散方
程式等で求める方法においても本発明の解決手段は有効
であり、本発明はベールの法則による演算方式に限定さ
れるものではない。また、前述の原理式に加えて使用す
る測定システム、特に光測定系の特性、などの数値も同
様にオフセット分として測定値に加わっており、本発明
の解決手段を用いて補正し、より正確な測定値を求める
ことが可能である。
Further, in the above embodiment, the equation for obtaining the oxygenated red blood cell amount is shown by Beer's law, but the solution of the present invention is also effective in the method of obtaining by the diffusion equation and the like. The calculation method is not limited to the law. In addition, the measurement system used in addition to the above-mentioned principle formula, especially the characteristics of the optical measurement system, etc. are also added to the measurement value as an offset amount, and are corrected by the solution means of the present invention to make it more accurate. It is possible to obtain various measured values.

【0099】更に、上記実施の形態では、光源として、
レーザーダイオードを用いたが、光源はレーザーダイオ
ードに限定されるものではなく、近接する4つの単光色
を発する発光素子であれば、気体、固定レーザー、発光
ダイオード等でもよい。
Further, in the above embodiment, as the light source,
Although the laser diode is used, the light source is not limited to the laser diode, and a gas, a fixed laser, a light emitting diode, or the like may be used as long as it is a light emitting element that emits four adjacent single light colors.

【0100】更にまた、上記実施の形態では、検出部に
電気的コネクタ3a,3b、電線5a,5b及びフォト
ダイオード7a,7bを用いて説明したが、測定光出力
部の光コネクタ2、光ファイバー4及びプローブ6と同
じ構成で、検出部を光コネクタ3、光ファイバー5及び
光ファイバー5の先端を加工した受光プローブ7のよう
に構成してもよい。但し、検出部を光コネクタ3、光フ
ァイバー5及び受光プローブ7で構成する場合、アンプ
16には光電気変換回路が含まれる。
Furthermore, in the above-mentioned embodiment, the electrical connectors 3a and 3b, the electric wires 5a and 5b, and the photodiodes 7a and 7b are used for the detecting section, but the optical connector 2 and the optical fiber 4 of the measuring light output section are used. Also, the detection unit may be configured like the optical connector 3, the optical fiber 5, and the light receiving probe 7 in which the tip of the optical fiber 5 is processed with the same configuration as the probe 6. However, when the detector is composed of the optical connector 3, the optical fiber 5, and the light receiving probe 7, the amplifier 16 includes a photoelectric conversion circuit.

【0101】[0101]

【発明の効果】以上本発明によれば、光による生体組織
中の血液量とその酸素飽和度測定において、2点以上の
測定点から得られた測定値を差分演算処理あるいは回帰
式による演算処理することで、生体組織自体の光吸収に
よって生じる測定値の不正確さを取り除くことができ
る。
As described above, according to the present invention, in the blood volume in living tissue and its oxygen saturation measurement by light, measurement values obtained from two or more measurement points are subjected to difference calculation processing or regression calculation processing. By doing so, it is possible to remove the inaccuracy of the measurement value caused by the light absorption of the living tissue itself.

【0102】これによって、個人間で皮膚の色素量が異
なっても、または組織自体の吸収係数が不明でも、酸素
化赤血球量、脱酸素化赤血球量および酸素飽和度を測
定、比較することが可能である。従って、生体組織内の
血液の酸素化度合を容易に直接測定できる生体組織血液
量測定装置を提供することができる。
As a result, it is possible to measure and compare the amount of oxygenated red blood cells, the amount of deoxygenated red blood cells and the degree of oxygen saturation even if the amount of skin pigment differs among individuals or the absorption coefficient of the tissue itself is unknown. Is. Therefore, it is possible to provide a biological tissue blood volume measuring device that can easily and directly measure the oxygenation degree of blood in the biological tissue.

【図面の簡単な説明】[Brief description of drawings]

【図1】 本発明の実施の形態にかかる生体組織血液量
測定装置の構成ブロック図である。
FIG. 1 is a configuration block diagram of a biological tissue blood volume measuring device according to an embodiment of the present invention.

【図2】 タイミング回路のパルスの説明図である。FIG. 2 is an explanatory diagram of pulses of a timing circuit.

【図3】 酸素化ヘモグロビンと脱酸素化ヘモグロビン
の光吸収係数の波長特性図である。
FIG. 3 is a wavelength characteristic diagram of light absorption coefficients of oxygenated hemoglobin and deoxygenated hemoglobin.

【図4】 2箇所の測定点での測定値の差分を求めた場
合の説明図である。
FIG. 4 is an explanatory diagram when a difference between measurement values at two measurement points is obtained.

【図5】 2箇所の測定点で測定した場合の測定点間距
離L1,L2と血液量VLの関係図である。
FIG. 5 is a relationship diagram between the distances L 1 and L 2 between the measurement points and the blood volume VL when the measurement is performed at two measurement points.

【図6】 従来の生体組織血液量測定装置の構成ブロッ
ク図である。
FIG. 6 is a configuration block diagram of a conventional biological tissue blood volume measuring device.

【図7】 従来技術で測定した場合の照射点と測定点間
距離Lと血液量VLの関係図である。
FIG. 7 is a relationship diagram of an irradiation point, a distance L between measurement points, and a blood volume VL when measured by a conventional technique.

【図8】 酸素化ヘモグロビンと脱酸素化ヘモグロビン
の光吸収係数の波長特性図
FIG. 8 is a wavelength characteristic diagram of light absorption coefficients of oxygenated hemoglobin and deoxygenated hemoglobin.

【符号の説明】[Explanation of symbols]

1 装置本体 2,3,3a,3b 光コネクタ 4,5 光ファイバー 5a,5b 電線 6 プローブ 7,7a,7b 光検出器 8 生体組織(組織) 11,12,13 光源(レーザダイオード) 15 光合波器 16,16a,16b 増幅部(アンプ) 17,17a,17b 演算処理回路 18 タイミング回路 20 補正部(差分演算) 1 device body 2,3,3a, 3b optical connector 4,5 optical fiber 5a, 5b electric wire 6 probes 7,7a, 7b Photodetector 8 Living tissue 11, 12, 13 Light source (laser diode) 15 Optical multiplexer 16, 16a, 16b Amplification unit (amplifier) 17, 17a, 17b Arithmetic processing circuit 18 Timing circuit 20 Correction unit (difference calculation)

フロントページの続き Fターム(参考) 2G059 AA01 AA05 BB12 BB13 CC16 CC18 EE01 EE02 EE11 GG01 GG02 GG08 HH01 HH02 HH06 JJ17 JJ22 KK03 MM01 PP04 4C038 KK01 KL05 KL07 KM01 KX02 KY03 KY04 Continued front page    F term (reference) 2G059 AA01 AA05 BB12 BB13 CC16                       CC18 EE01 EE02 EE11 GG01                       GG02 GG08 HH01 HH02 HH06                       JJ17 JJ22 KK03 MM01 PP04                 4C038 KK01 KL05 KL07 KM01 KX02                       KY03 KY04

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】3種類以上の測定光を所定の強度で生体組
織に対し直接照射する測定光出力部と、 前記出力された測定光が前記生体組織を通過した透過散
乱光の強度を2点以上の測定点で検出する検出部と、 前記出力された測定光と前記検出された透過散乱光の強
度差から得られる前記生体組織中の光吸収量に基づき前
記生体組織中の全血液の酸素化度合、または全赤血球量
に対する酸素化赤血球量の割合である酸素化度合、酸素
化赤血球量と脱酸素化赤血球量を演算する酸素化度合演
算部と、 前記2点以上の測定点から、前記演算した酸素化度合、
酸素化赤血球量と脱酸素化赤血球量に対し生体組織自体
の光吸収度合より生じる誤差を補正する補正部とを備え
たことを特徴とする生体組織血液量測定装置。
1. A measurement light output section for directly irradiating a living tissue with three or more kinds of measurement light at a predetermined intensity, and two points of intensity of transmitted scattered light which the output measurement light has passed through the living tissue. Detection unit to detect at the above measurement points, oxygen of whole blood in the biological tissue based on the amount of light absorption in the biological tissue obtained from the intensity difference between the output measurement light and the detected transmitted scattered light Degree of oxygenation, the degree of oxygenation, which is the ratio of the amount of oxygenated red blood cells to the total amount of red blood cells, the degree of oxygenation calculation unit that calculates the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells, from the two or more measurement points, the Calculated oxygenation degree,
A biological tissue blood volume measuring device comprising: a correction unit that corrects an error caused by the degree of light absorption of the biological tissue itself with respect to the amount of oxygenated red blood cells and the amount of deoxygenated red blood cells.
【請求項2】前記補正部は、前記測定点が2点の場合、
前記測定値の差分を求めて前記誤差を補正する請求項1
に記載の生体組織血液量測定装置。
2. The correction unit, when the number of measurement points is 2,
The error is corrected by obtaining a difference between the measured values.
The biological tissue blood volume measuring device according to.
【請求項3】前記補正部は、前記測定点が3点以上の場
合、回帰式から前記測定値の回帰直線の傾きを求めて前
記誤差を補正する請求項1に記載の生体組織血液量測定
装置。
3. The biological tissue blood volume measurement according to claim 1, wherein the correction unit corrects the error by obtaining a slope of a regression line of the measurement value from a regression equation when the number of measurement points is three or more. apparatus.
JP2001400431A 2001-12-28 2001-12-28 Measuring apparatus for blood amount in living-body tissue Pending JP2003194714A (en)

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