JP2795197B2 - Optical scattering / absorber measuring device - Google Patents
Optical scattering / absorber measuring deviceInfo
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- JP2795197B2 JP2795197B2 JP6309719A JP30971994A JP2795197B2 JP 2795197 B2 JP2795197 B2 JP 2795197B2 JP 6309719 A JP6309719 A JP 6309719A JP 30971994 A JP30971994 A JP 30971994A JP 2795197 B2 JP2795197 B2 JP 2795197B2
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- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は生体酸素モニタなどの光
散乱・吸収体の光学的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 device for a light scattering / absorbing material such as a biological oxygen monitor.
【0002】[0002]
【従来の技術】酸素モニタでは被検体の一部に測定光を
入射し、その被検体の他の部分から出てくる光を検出
し、複数の波長で測定した吸光度変化量の重みつき一次
結合として目的成分の変化量を求めている。その方法を
具体的に示すと、酸素化ヘモグロビン、脱酸素化ヘモグ
ロビンの濃度変化量をそれぞれΔ〔HbO2〕、Δ〔H
b〕とし、散乱成分等による平行移動量をSと表し、波
長λ1、λ2、λ3に対する酸素化ヘモグロビンの分子吸
光度をそれぞれe1,e2,e3、脱酸素化ヘモグロビン
の分子吸光度をそれぞれb1,b2,b3とすれば、波長
λ1,λ2,λ3についてヘモグロビン濃度と吸光度の線
形性を仮定して、対応する吸光度変化ΔA1、ΔA2、Δ
A3は ΔA1=e1Δ〔HbO2〕+b1Δ〔Hb〕+S ΔA2=e2Δ〔HbO2〕+b2Δ〔Hb〕+S ΔA3=e3Δ〔HbO2〕+b3Δ〔Hb〕+S ……(a) とかける。これをΔ〔HbO2〕、Δ〔Hb〕、Sを未
知数とする連立方程式として解けば、 Δ〔HbO2〕=k11ΔA1+k12ΔA2+k13ΔA3 Δ〔Hb〕 =k21ΔA1+k22ΔA2+k23ΔA3 ……(b) の形の解が得られる。また(a)式で散乱成分等による
平行移動量Sを考慮しない方法も可能であり、その場合
はS=0として解けば、未知数が2つで式が3つになる
ので、最小自乗法で解けばよく、解の形はやはり(b)
式になる。2. Description of the Related Art In an oxygen monitor, measurement light is incident on a part of an object, light emitted from another part of the object is detected, and a weighted linear combination of absorbance changes measured at a plurality of wavelengths is obtained. And the amount of change in the target component is determined. Specifically, the method is as follows: the changes in the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin are Δ [HbO 2 ] and Δ [H
b], the amount of translation due to scattering components and the like is represented as S, and the molecular absorbances of oxygenated hemoglobin for wavelengths λ 1 , λ 2 , and λ 3 are e 1 , e 2 , e 3 , and the molecular absorbances of deoxygenated hemoglobin, respectively Are assumed to be b 1 , b 2 , and b 3 , respectively, and assuming the linearity of hemoglobin concentration and absorbance for wavelengths λ 1 , λ 2 , and λ 3 , the corresponding absorbance changes ΔA 1 , ΔA 2 , and Δ
A 3 is ΔA 1 = e 1 Δ [HbO 2 ] + b 1 Δ [Hb] + S ΔA 2 = e 2 Δ [HbO 2 ] + b 2 Δ [Hb] + S ΔA 3 = e 3 Δ [HbO 2 ] + b 3 Δ [Hb] + S (a) Solving this as a simultaneous equation with Δ [HbO 2 ], Δ [Hb], and S as unknowns, Δ [HbO 2 ] = k 11 ΔA 1 + k 12 ΔA 2 + k 13 ΔA 3 Δ [Hb] = k 21 ΔA 1 + k 22 ΔA 2 + k 23 ΔA 3 A solution of the form (b) is obtained. In addition, a method that does not consider the translation amount S due to the scattering component or the like in the equation (a) is also possible. In this case, if S = 0 is solved, the number of unknowns becomes two and the number of equations becomes three. You only need to solve, and the shape of the solution is still (b)
Expression.
【0003】一方、均一な光散乱・吸収体の特性は吸収
係数μaと等価散乱係数μs’(=(1−g)μs;μ
sは散乱係数、gは非等方性パラメータ)の2つの光学
定数により記述することができる。図1に示されるよう
に、半無限体の一部に単位1のデルタ関数のパルス光を
時刻0に入射させ、その入射点からρmm離れた点の1
mm2から時刻tに出る光の強度R(ρ,t)は次の
(1)式で与えられる(APPLIED OPTICS, Vol.28, No.1
2, pp.2331-2336 (1989)参照)。On the other hand, the characteristics of a uniform light scattering / absorbing material include an absorption coefficient μa and an equivalent scattering coefficient μs ′ (= (1−g) μs; μ).
s is a scattering coefficient, and g is an anisotropic parameter). As shown in FIG. 1, a pulse light of a delta function of unit 1 is incident on a part of a semi-infinite body at time 0, and 1 point ρmm away from the incident point
The intensity R (ρ, t) of light emitted from mm 2 at time t is given by the following equation (1) (APPLIED OPTICS, Vol. 28, No. 1).
2, pp.2331-2336 (1989)).
【0004】[0004]
【数1】 (Equation 1)
【0005】ここで、Dは拡散係数であり、D=1/3
(μa+μs’)、cは媒体中での光速、Z0=1/μ
s’である。入射点から一定の距離だけ離れた受光点で
光の強度を時間分解法により測定し、(1)式にあては
めれば、光学定数μaとμs’を個々に求めることがで
き、現在その方向での検討が進められている。[0005] Here, D is a diffusion coefficient, and D = 1/3.
(Μa + μs ′), c is the speed of light in the medium, Z 0 = 1 / μ
s'. When the light intensity is measured by a time-resolved method at a light receiving point at a certain distance from the incident point, and applied to the equation (1), the optical constants μa and μs ′ can be obtained individually, and the current Examination is underway.
【0006】[0006]
【発明が解決しようとする課題】従来の酸素モニタでの
測定は、測定開始点を零として、それからの変化量の測
定に限られており、絶対量の測定はなされていない。絶
対量を測定しようとすれば、現在のところ時間分解法に
より求める方法しか検討がなされていないが、時間分解
法は装置が大型となり、価格も高価となるので、簡易な
測定装置としては実現することができない。そのため、
定常光法で光学定数の絶対値を求めることが長らく求め
られてきたが、これまで有用な方法が見出されていな
い。The measurement by the conventional oxygen monitor is limited to measurement of a change starting from a measurement start point of zero, and measurement of an absolute amount is not performed. At present, only a method of obtaining an absolute amount is measured by a time-resolved method. However, the time-resolved method requires a large device and is expensive, so that it can be realized as a simple measuring device. Can not do. for that reason,
Obtaining the absolute value of the optical constant by the stationary light method has long been required, but no useful method has been found so far.
【0007】本発明は定常光法で光学定数の絶対測定を
行なう装置を提供することを目的とするものである。こ
こで、絶対量とはその時点の量であればよく、それが単
位を持たない比の形であるか、特定の単位を有する本来
の絶対量であるかは問わない。特定の時刻からの変化分
だけの測定量でなく、その時点の測定量を絶対量と称す
ことにする。SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for performing absolute measurement of an optical constant by a stationary light method. Here, the absolute amount may be an amount at that time, and it does not matter whether it is in the form of a ratio having no unit or an original absolute amount having a specific unit. The measured quantity at that point in time is referred to as the absolute quantity, not the measured quantity only for the change from a specific time.
【0008】[0008]
【課題を解決するための手段】本発明は、検出した光か
ら被検体の吸収係数μaと等価散乱係数μs’の積μa
・μs’を一括した量として算出する演算部を備えた測
定装置である。本発明者らは、被検体の1点に入射した
光が入射点から距離を離れた点から再放射される強さの
理論式において積μa・μs’が常に一括して現れるこ
と、並びに再放射される光の強さを入射点からの距離の
関数として測定すれば、時間分解法を用いることなく積
μa・μs’の絶対値を求めることができることを見出
した。さらに複数の波長で求められた、複数個の(μa
・μs’)の組の間の比を計算すれば、被検体のμaの
比率という意味での被検体の酸素化度の絶対値(変化量
ではないその時点の値)を算出することができることを
見出した。これは後述するようにμs’の波長依存性が
各検体についてほぼ等しいので、複数波長の(μa・μ
s’)の組の間の比によりμs’が消去されμaだけが
残るという理由による。According to the present invention, a product μa of an absorption coefficient μa of an object and an equivalent scattering coefficient μs ′ is obtained from detected light.
A measurement device including a calculation unit that calculates μs ′ as a collective amount. The present inventors have found that the product μa · μs ′ always appears collectively in the theoretical formula of the intensity at which light incident on one point of the subject is re-emitted from a point distant from the point of incidence; It has been found that by measuring the intensity of the emitted light as a function of the distance from the point of incidence, the absolute value of the product μa · μs ′ can be determined without using a time-resolved method. Furthermore, a plurality of (μa
Calculating the ratio between the pairs (μs ′), it is possible to calculate the absolute value of the oxygenation degree of the subject in the sense of the ratio of μa of the subject (the value at that time, not the amount of change). Was found. This is because, as will be described later, the wavelength dependence of μs ′ is substantially equal for each sample, so that a plurality of wavelengths (μa · μ
This is because the ratio between the pairs of s ′) erases μs ′ and only μa remains.
【0009】本発明の前記μa・μs’を求める演算を
受光点が2ヵ所であるときの最も簡単な例で述べれば次
の通りである。すなわち、1つの受光点と入射点との距
離をa1、その受光点での受光強度をI1とし、他の受光
点と入射点との距離をa2、その受光点での受光強度を
I2としたとき、 lnI2−lnI1 =−(a2−a1)B+ln(a2B+1)−ln(a1B+1)−3ln(a2/a1) に基づいてμa・μs’を求める。ただし、B=(3μa
・μs)1/2である。The operation for obtaining μa · μs ′ of the present invention will be described in the following simplest example when the number of light receiving points is two. That is, the distance between one light receiving point and the incident point is a 1 , the light receiving intensity at the light receiving point is I 1 , the distance between the other light receiving point and the incident point is a 2 , and the light receiving intensity at the light receiving point is Assuming I 2 , μa · μs ′ is calculated based on lnI 2 −lnI 1 = − (a 2 −a 1 ) B + ln (a 2 B + 1) −ln (a 1 B + 1) −3 ln (a 2 / a 1 ) Ask. However, B = (3 μa
Μs) 1/2 .
【0010】一般的に、(μa・μs’)を1つの定数
として扱えば、定常光による絶対測定が可能であること
を示す。定常光の扱いは(1)式を時間積分すればよ
く、その結果は次の(2)式になる。In general, if (μa · μs ′) is treated as one constant, it indicates that absolute measurement using stationary light is possible. For the treatment of the stationary light, the expression (1) may be integrated over time, and the result is the following expression (2).
【0011】[0011]
【数2】 (Equation 2)
【0012】ここで、拡散係数D=1/3(μa+μ
s’)において、μaはμs’の約1/100であるの
で、μaは無視することができ、D=1/3μs’とし
ても全く差し支えがない。これを、(2)式に代入し、
またa=(ρ2+Z0 2)1/2とおけば、次の(3)式とな
る。Here, the diffusion coefficient D = 1/3 (μa + μ
In s ′), μa is about 1/100 of μs ′, so μa can be neglected, and D = 1/3 μs ′ is completely acceptable. Substituting this into equation (2),
If a = (ρ 2 + Z 0 2 ) 1/2 , the following equation (3) is obtained.
【0013】[0013]
【数3】 (Equation 3)
【0014】(3)式では(μa・μs’)が1つの積
の形で一緒に現れていることが注目される。このこと
は、定常光方式ではμaとμs’は区別できず、常に一
括して扱わざるを得ないことを意味している。しかし、
(μa・μs’)を1つの光学定数と考えると、(3)
式の光学定数はただ1つになるので、計算で求めること
が容易になる。なお、測定を多波長で行なえば、(μa
・μs’)は各波長ごとに求まるので、後述するように
各波長での(μa・μs’)の比を求める演算につなげ
ることができる。In equation (3), it is noted that (μa · μs ′) appears together in the form of one product. This means that μa and μs ′ cannot be distinguished in the stationary light system and must always be treated collectively. But,
Considering (μa · μs ′) as one optical constant, (3)
Since there is only one optical constant in the equation, it is easy to obtain it by calculation. If measurement is performed at multiple wavelengths, (μa
.Mu.s ') is obtained for each wavelength, so that it can be connected to an operation for calculating the ratio of (.mu.a..mu.s') at each wavelength, as described later.
【0015】さて、(3)式において B=(3μa・μs)1/2 ……(4) とおくと、(3)式はBy the way, in the equation (3), B = (3 μa · μs) 1/2 (4)
【0016】[0016]
【数4】 (Equation 4)
【0017】となる。(5)式の自然対数をとると、 lnR(a,B) =−aB+ln(aB+1)−3lna+C ……(6) となる。Cは定数で、 ln(Z0/2π)=C ……(7) とおいた。## EQU1 ## Taking the natural logarithm of equation (5), lnR (a, B) =-aB + ln (aB + 1) -3lna + C (6) C is a constant, and is set as ln (Z 0 / 2π) = C (7).
【0018】(6)式において、lnR(a,B)をyと
おけば、 y=−aB+ln(aB+1)−3lna+C ……(6’) となる。(6’)式を、Bをパラメータとし、yをaの
関数として描くと図2のようになり、B(すなわちμa
・μs’)が大きい程、図の右下りの勾配が大きいこと
が分かる。In equation (6), if lnR (a, B) is y, then y = -aB + ln (aB + 1) -3lna + C (6 '). When the equation (6 ′) is drawn with B as a parameter and y as a function of a, it becomes as shown in FIG.
It can be seen that the greater the value of μs ′), the greater the slope of the graph in the right direction.
【0019】(3)式を導くときは a=(ρ2+z0 2)1/2 としたが、このaは送受光部間距離ρとほとんど等しい
ので、aも送受光部間距離と呼ぶ。Z0は約1mmであ
るので、例えばρ=20mmとすれば、a=20.02
mmとなり、aはほとんどρに等しい。そこで、実際の
測定ではaの値としてρの測定値を用いる。When the equation (3) is derived, a = (ρ 2 + z 0 2 ) 1/2 . However, since a is almost equal to the distance ρ between the light transmitting and receiving parts, a is also called the distance between the light transmitting and receiving parts. . Since Z 0 is about 1 mm, for example, if ρ = 20 mm, a = 20.02
mm, and a is almost equal to ρ. Therefore, in the actual measurement, the measured value of ρ is used as the value of a.
【0020】( B=(3μa・μs)1/2の決定方法
) つぎに、Bを決定する方法を説明する。送受光部間距離
を変えた図2の関数y(a)(=lnR(a,B))から逆
にBを求める。(6’)式の未知数はCとBの2つであ
るので、2種以上の送受光部間距離aについて(6’)
式の測定結果が求まっておれば、BとCが求まる。ま
た、連続的又は多数のaについての測定結果があれば、
それらの測定結果を図2の曲線に最小2乗法で合わせる
ことにより、一層正確にBとCを求めることができる。
そのため、本発明の装置は、被検体の一部に測定光を入
射し、その被検体上で前記測定光の入射点から異なる距
離だけ離れた複数の受光点で測定光を受光する測定光学
系と、これら複数の受光点で測定光を受光したときの各
検出器の出力を、送光点と受光点の距離aiの関数とし
て測定した結果をR(ai),i=1,2,3……(i
は検出器の番号)とするとき、これら検出器の個数だけ
の測定値R(ai)に対し、(5)式に示されるように、
理論式から予測されるパラメータB(=(3μa・μ
s’)1/2)を含む関数R(ai,B)を等値して得られ
る連立方程式よりBを求め、これより積μa・μs’を
求める演算部を備えている。(B = (3 μa · μs) 1/2 Determination Method
Next, a method for determining B will be described. Conversely, B is obtained from the function y (a) (= lnR (a, B)) in FIG. 2 in which the distance between the light transmitting and receiving units is changed. Since the unknowns in the equation (6 ′) are two, C and B, the distance a between two or more types of light transmitting / receiving sections is (6 ′)
If the measurement result of the formula is obtained, B and C are obtained. Also, if there are continuous or multiple measurement results for a,
By fitting the measurement results to the curve of FIG. 2 by the least square method, B and C can be obtained more accurately.
Therefore, the apparatus of the present invention is a measuring optical system that receives measuring light at a plurality of light receiving points separated by different distances from the incident point of the measuring light on the subject, the measuring light being incident on a part of the subject. And R (ai), i = 1,2,3, where the output of each detector when the measurement light is received at these plurality of light receiving points is measured as a function of the distance ai between the light transmitting point and the light receiving point. ...... (i
Is the number of the detectors), and the measured values R (ai) corresponding to the number of the detectors are expressed by the following equation (5).
Parameter B (= (3 μa · μ) predicted from the theoretical formula
s ′) 1/2 ), and an arithmetic unit for obtaining B from a simultaneous equation obtained by equalizing a function R (ai, B) including the function R (ai, B) and obtaining a product μa · μs ′ from the simultaneous equation.
【0021】以下に、最も簡単な場合として、2つの送
受光部間距離a1とa2についての測定結果が与えられた
とき、Bを求める数値計算を試みる。a=a1,a2につ
いて(6)式を作り、その差をとればCが消え、次の式
を得る。 lnR(a2,B)−lnR(a1,B) =−(a2−a1)B+ln(a2B+1)−ln(a1B+1)−3ln(a2/a1) ……(8) これを図示したのが、図3である。ここで、見やすくす
るために、 lnR(a2,B)=y2、lnR(a1,B)=y1 とおいて、(8)式をf(B)=0の形にすれば、 f(B)=(a2−a1)B−ln(a2B+1)+ln(a1B+1)+(y2−y1) +3ln(a2/a1) ……(9) となる。このf(B)=0なる方程式を解いて、Bを求
めればよい。In the following, as the simplest case, a numerical calculation for obtaining B is attempted when the measurement results for the distances a 1 and a 2 between the two light transmitting / receiving sections are given. Formula (6) is created for a = a 1 and a 2 , and if the difference is taken, C disappears and the following formula is obtained. lnR (a 2 , B) −lnR (a 1 , B) = − (a 2 −a 1 ) B + ln (a 2 B + 1) −ln (a 1 B + 1) −3 ln (a 2 / a 1 ) (8) FIG. 3 illustrates this. Here, in order to make it easy to see, if lnR (a 2 , B) = y 2 and lnR (a 1 , B) = y 1, and formula (8) is f (B) = 0, f (B) = (a 2 −a 1 ) B−ln (a 2 B + 1) + ln (a 1 B + 1) + (y 2 −y 1 ) +3 ln (a 2 / a 1 ) (9) By solving the equation of f (B) = 0, B may be obtained.
【0022】次に、その求め方を説明する。Bが未知数
であるので、分かりやすいようにBをxとおき、 f(x)=(a2−a1)x−ln(a2x+1)+ln(a1x+1)+(y2−y1) +3ln(a2/a1) ……(9’) と書き直す。Bを求めることは、f(x)=0を満たす
xを求めることに相当する。Next, how to obtain the above will be described. Since B is an unknown number, B is set to x for easy understanding, and f (x) = (a 2 −a 1 ) x−ln (a 2 x + 1) + ln (a 1 x + 1) + (y 2 −y 1 ) + 3ln (a 2 / a 1 )... (9 ′). Finding B is equivalent to finding x that satisfies f (x) = 0.
【0023】(9’)式のf(x)の典型的な例を図示
すると、図4のようになる。(y2−y1)は吸光度差で
あり、図4にはこの吸光度差が2種類の場合を示してい
る。この図からそれぞれf(x)=0となるxは、x1=
0.045、x2=0.15となり、それらが解である。
ニュートン法などの簡単な数値解法により、f(x)=
0の解を求めることができる。FIG. 4 shows a typical example of f (x) in the equation (9 '). (Y 2 −y 1 ) is the absorbance difference, and FIG. 4 shows the case where the absorbance difference is of two types. From this figure, x at which f (x) = 0 is obtained by x 1 =
0.045, x 2 = 0.15, which are the solutions.
By a simple numerical solution such as Newton's method, f (x) =
A solution of 0 can be obtained.
【0024】f(x)=0の解を実際に解いた例を図5
(A)と(B)に示す。2つの距離に対する吸光度の差
Δyが横軸に与えられ、対応するBを縦軸に読み取るこ
とができる。(B)は(A)の縦軸を拡大したものであ
る。パラメータとしてa1,a2を用いている。a1=1
0mmとし、a2を20,30,50mmと変えた。FIG. 5 shows an example in which the solution of f (x) = 0 is actually solved.
(A) and (B) show. The difference Δy in absorbance for the two distances is given on the horizontal axis, and the corresponding B can be read on the vertical axis. (B) is an enlarged vertical axis of (A). A 1 and a 2 are used as parameters. a 1 = 1
A2 was changed to 20 , 30, and 50 mm.
【0025】図5のようなΔyとBの関係を表わす表を
装置に組み込んでおけば、入射点からの距離が異なる受
光部を有するプローブを用いて以下のようにB値を求め
ることができる。すなわち、図6に示すプローブは、送
光用光ファイバ6により被検体2の一部に測定光を入射
させ、入射点からそれぞれa1,a2離れた受光点に検出
器D1とD2をおいて光信号を検出する。それぞれの検出
光信号をI1,I2とする。6は送光用ファイバ4と検出
器D1,D2を支持しているプローブである。検出器D1
とD2は同じ感度になるように較正しておく。例えば検
出器D2をD1の位置におくとき、出力が等しくなるよう
にするなどの方法で較正しておく。If a table showing the relationship between Δy and B as shown in FIG. 5 is incorporated in the apparatus, the B value can be obtained as follows using a probe having a light receiving portion having a different distance from the incident point. . That is, in the probe shown in FIG. 6, the measuring light is made incident on a part of the subject 2 by the light transmitting optical fiber 6, and the detectors D 1 and D 2 are respectively received at light receiving points a 1 and a 2 away from the incident point. At which the optical signal is detected. Let the respective detected light signals be I 1 and I 2 . Reference numeral 6 denotes a probe supporting the light transmitting fiber 4 and the detectors D 1 and D 2 . Detector D 1
And D 2 is kept calibrated to have the same sensitivity. For example, when placing the detector D 2 to the position of the D 1, the output is kept calibrated by a method such as to be equal.
【0026】lnI1=y1、lnI2=y2とすると、 Δy=−(y2−y1) となる。If lnI 1 = y 1 and lnI 2 = y 2 , then Δy = − (y 2 −y 1 ).
【0027】図6のプローブで、a1=10mm、a2=
30mmとすれば、図5の曲線Aを測定装置に記憶させ
ておけばよい。仮にΔy=7であったとすれば、B値と
してB=0.23が得られ、これからμa・μs’=B2
/3=0.0176が得られる。多波長測定を行なえ
ば、各波長に対してのB、及びそれから導かれる各波長
に対するμa・μs’が得られる。In the probe of FIG. 6, a 1 = 10 mm and a 2 =
If it is 30 mm, the curve A in FIG. 5 may be stored in the measuring device. Assuming that Δy = 7, B = 0.23 is obtained as the B value, and μa · μs ′ = B 2
/3=0.0176 is obtained. By performing multi-wavelength measurement, B for each wavelength and μa · μs ′ for each wavelength derived therefrom can be obtained.
【0028】図5の縦軸をBからμa・μs’に変換し
たものを図7に示す。単にμa・μs’=B2/3により
変換したものである。図7では、Δyが増えるとμa・
μs’が急上昇することが注目される。FIG. 7 shows the vertical axis of FIG. 5 converted from B to μa · μs ′. But merely converted by μa · μs' = B 2/ 3. In FIG. 7, when Δy increases, μa ·
It is noted that μs' soars.
【0029】( μa・μs’の利用法と有用性 )次
に、μa・μs’の利用法と有用性について説明する。
μa・μs’をμas’と表わす。 μas’=μa・μs’……(10) これが各波長、例えばλ1,λ2,λ3で求められ、各時
刻tで求められているとする。すなわち μas'(λi,t) (i=1,2,3) である。(Utilization and Usefulness of μa · μs ′) Next, utilization and usefulness of μa · μs ′ will be described.
μa · μs ′ is expressed as μas ′. μas ′ = μa · μs ′ (10) It is assumed that this is obtained at each wavelength, for example, λ 1 , λ 2 , λ 3 , and is obtained at each time t. That is, μas ′ (λi, t) (i = 1, 2, 3).
【0030】この光学定数μas’が積の形になってい
る利点は、μs’は短波長側でやや大きくなるものの、
波長依存性は小さいと考えられており、かつ波長依存性
f(λ)と試料依存性とに分離できることである。そこ
で、 μs’=f(λi)・s(t) ……(11) と表わす。f(λi)は波長依存項、s(t)は個別の検体
と時間tによる項で、波長によらない項である。The advantage that the optical constant μas ′ is in the form of a product is that although μs ′ is slightly larger on the short wavelength side,
It is considered that the wavelength dependency is small, and the wavelength dependency f (λ) can be separated into the sample dependency. Therefore, μs ′ = f (λi) · s (t) (11) f (λi) is a wavelength-dependent term, and s (t) is a term based on an individual sample and time t, and is a term independent of wavelength.
【0031】(10)式の値を例えば3波長について求
め、それらの比をとると、s(t)が消え、次のようにな
る。 m1=μas'(λ1)/μas'(λ3) =(f(λ1)/f(λ3))(μa(λ1)/μa(λ3)) =f13・(μa(λ1)/μa(λ3)) m2=μas'(λ2)/μas'(λ3) =(f(λ2)/f(λ3))(μa(λ2)/μa(λ3)) =f23・(μa(λ2)/μa(λ3)) 故に、 μa(λ1)=μa(λ3)×(m1/f13) μa(λ2)=μa(λ3)×(m2/f23) ……(12) が得られる。これから吸収係数の比が求まる。すなわ
ち、 μa(λ1):μa(λ2):μa(λ3) (m1/f13):(m2/f23):1 ……(13)When the value of the equation (10) is obtained for, for example, three wavelengths and their ratio is calculated, s (t) disappears, and the following is obtained. m 1 = μas '(λ 1 ) / μas' (λ 3 ) = (f (λ 1 ) / f (λ 3 )) (μa (λ 1 ) / μa (λ 3 )) = f 13 · (μa ( λ 1 ) / μa (λ 3 )) m 2 = μas ′ (λ 2 ) / μas ′ (λ 3 ) = (f (λ 2 ) / f (λ 3 )) (μa (λ 2 ) / μa (λ 3)) = hence f 23 · (μa (λ 2 ) / μa (λ 3)), μa (λ 1) = μa (λ 3) × (m 1 / f 13) μa (λ 2) = μa (λ 3 ) × (m 2 / f 23 ) (12) From this, the ratio of the absorption coefficients is determined. That is, μa (λ 1 ): μa (λ 2 ): μa (λ 3 ) (m 1 / f 13 ) :( m 2 / f 23 ): 1 (13)
【0032】もし、吸収係数μa(λ1),μa(λ2)及び
μa(λ3)がそれぞれ酸素化ヘモグロビン量[Hb
O2]、ヘモグロビン量[Hb]及びチトクロムオキシ
ダーゼ量[Cyt]のみからきたものであるとすれば、
上記3波長の比からこれらの成分の量比が求まることに
なり、従来は変化量Δ[HbO2]、Δ[Hb]及びΔ
[Cyt]の比しか求められなかった状態から、絶対値
の比が求められるところまで進歩したことになる。すな
わち、変化量ではなく、比としてのその時点の量が求め
られる。If the absorption coefficients μa (λ 1 ), μa (λ 2 ) and μa (λ 3 ) are the oxygenated hemoglobin amounts [Hb
O 2 ], the amount of hemoglobin [Hb] and the amount of cytochrome oxidase [Cyt] alone,
The ratio of these components is determined from the ratio of the three wavelengths. Conventionally, the change amounts Δ [HbO 2 ], Δ [Hb] and Δ
This means that progress has been made from the state where only the ratio of [Cyt] is obtained to the point where the ratio of absolute values is obtained. That is, the amount at that point in time as a ratio is obtained instead of the amount of change.
【0033】μaの各波長の比を表わす量は、酸素化度
の情報である。一方、血液量の情報はμaの絶対値と
(11)式のs(t)の方に含まれているので、(13)
式の比によっては評価することはできない。しかし、等
吸収点(λ=805nm)におけるμas’=μa(80
5)×μs'(805)が血液量の情報を与える。The quantity representing the ratio of each wavelength of μa is information on the degree of oxygenation. On the other hand, since the information on the blood volume is included in the absolute value of μa and s (t) in equation (11),
It cannot be evaluated depending on the ratio of the equations. However, μas ′ = μa (80 at the isosbestic point (λ = 805 nm)
5) xμs' (805) gives blood volume information.
【0034】実用上の光入射点と受光点との間隔では、
図5のBとΔyの関係は直線に近似することができる。
すなわち、 B=αΔy+β (14) という近似が成り立つ。この近似を用いると、(4)式
は、 μa・μs'=(1/3)・(αΔy+β)2 μa=(1/μs')・(1/3)・(αΔy+β)2 (15) となる。ここで、μs’の波長依存性のみを分離し、 μs'=μs'(λ0)・f(λ) (16) と書けば、 μa=(1/μs'(λ0))・〔(1/f(λ))・(1/3)・(αΔy+β)2〕 (17) となる。(17)式の右辺の〔(1/f(λ))・(1/3)・
(αΔy+β)2〕を、 m=(1/f(λ))・(1/3)・(αΔy+β)2 =(1/f(λ))・(p・Δy2+q・Δy+r) (18) とおけば、 μa=(1/μs'(λ0))・m であり、μaは比例係数(1/μs'(λ0))でmに比例
する。In a practical interval between the light incident point and the light receiving point,
The relationship between B and Δy in FIG. 5 can be approximated to a straight line.
That is, the approximation B = αΔy + β (14) holds. Using this approximation, equation (4) gives: μa · μs ′ = (1/3) · (αΔy + β) 2 μa = (1 / μs ′) · (1/3) · (αΔy + β) 2 (15) Become. Here, only the wavelength dependence of μs ′ is separated, and if μs ′ = μs ′ (λ 0 ) · f (λ) (16), then μa = (1 / μs ′ (λ 0 )) · (( 1 / f (λ)) · (1/3) · (αΔy + β) 2 ] (17) [(1 / f (λ)) · (1/3) ·
(αΔy + β) 2 ], m = (1 / f (λ)) · (1/3) · (αΔy + β) 2 = (1 / f (λ)) · (p · Δy 2 + q · Δy + r) (18) Then, μa = (1 / μs ′ (λ 0 )) · m, and μa is proportional to m with a proportional coefficient (1 / μs ′ (λ 0 )).
【0035】さて、(18)式のp,q,rの値は試料
によらず、検出部の光入射点−受光点間間隔a1,a2で
決まる。mの(18)式による近似が良好なものである
ことを示すために、B値を直接(8)式で解いたときの
μa・μs’値と、(18)式によるmの値とを1/μ
s'(λ0)=1として比較した。この例では、光入射点と
受光点の間の間隔はa1=25mm、a2=45mmと
し、p,q,rの値はその場合に(8)式が適合するよ
うに定めて(18)式から次の式を得て計算を行なっ
た。 m=0.000857913・Δy2−0.00225859・Δy+0.001486526 表1はその結果を示したものであり、きわめてよく一致
している。Now, the values of p, q, and r in the equation (18) are determined by the intervals a 1 and a 2 between the light incident point and the light receiving point of the detector, regardless of the sample. In order to show that the approximation of m according to equation (18) is good, the μa · μs ′ value when the B value is directly solved by equation (8) and the value of m according to equation (18) 1 / μ
The comparison was made with s' (λ 0 ) = 1. In this example, the distance between the light incident point and the light receiving point is a 1 = 25 mm and a 2 = 45 mm, and the values of p, q, and r are determined so that the equation (8) is adapted in that case (18). The calculation was performed by obtaining the following equation from the equation). m = 0.000857913 · Δy 2 −0.00225859 · Δy + 0.001486526 Table 1 shows the results, which are in very good agreement.
【0036】[0036]
【表1】 Δy 正しい 二次式によるm値 μa・μs’値 (μs'=1) 3.5 0.004027
0.004091 4 0.006156
0.006179 5 0.011675
0.011641 6 0.018868
0.018820 7 0.027732
0.027714 8 0.038266
0.038324Table 1 Δy Correct m value by quadratic equation μa · μs ′ value (μs ′ = 1) 3.5 0.004027
0.004091 4 0.006156
0.006179 5 0.011675
0.011641 6 0.018868
0.018820 7 0.027732
0.027714 8 0.038266
0.038324
【0037】このようにして得られたmの値は、比例係
数を除いて散乱体により抽出されたμaの値であると考
えてよいので、純粋な系における連立方程式が成立す
る。2成分系のオキシヘモグロビン、デオキシヘモグロ
ビンの3波長測定を例にとれば、 (1/2.303)・m(λ1)/f(λ1)=ε1(λ1)・〔HbO2〕+ε2(λ1)・〔Hb〕 (1/2.303)・m(λ2)/f(λ2)=ε1(λ2)・〔HbO2〕+ε2(λ2)・〔Hb〕 (1/2.303)・m(λ3)/f(λ3)=ε1(λ3)・〔HbO2〕+ε2(λ3)・〔Hb〕 (19) となる。ここで〔HbO2〕,〔Hb〕はそれぞれオキ
シヘモグロビン、デオキシヘモグロビンの濃度(比例係
数を除いている)である。ε1(λi),ε2(λi)(i=
1,2,3)はそれぞれオキシヘモグロビン、デオキシ
ヘモグロビンの各波長での分子吸光係数である。(a)
式と異なるのは、〔HbO2〕,〔HbO2〕の前に変化
量を示すΔマークが付いていないことである。また、
(19)式のε1(λi),ε2(λi)は純粋な溶液に対す
る吸光係数であるので、文献値を用いることができるの
に対し、(a)式の係数e1,e2,e3,b1,b2,b3
は散乱成分を含む個々の系での実験によって定めなけれ
ばならない不便がある。なお、(19)式の(1/2.303)
という数値は、左辺の量が自然対数に基づいているのに
対し、右辺の分子吸光係数が常用対数に基づいているた
めの換算係数である。Since the value of m obtained in this manner can be considered to be the value of μa extracted by the scatterer excluding the proportional coefficient, a simultaneous equation in a pure system is established. Taking three-wavelength measurement of two-component oxyhemoglobin and deoxyhemoglobin as an example, (1 / 2.303) · m (λ 1 ) / f (λ 1 ) = ε 1 (λ 1 ) · [HbO 2 ] + ε 2 (λ 1 ) · [Hb] (1 / 2.303) · m (λ 2 ) / f (λ 2 ) = ε 1 (λ 2 ) · [HbO 2 ] + ε 2 (λ 2 ) · [Hb] (1 / 2.303) · m (λ 3 ) / f (λ 3 ) = ε 1 (λ 3 ) · [HbO 2 ] + ε 2 (λ 3 ) · [Hb] (19) Here, [HbO 2 ] and [Hb] are the concentrations of oxyhemoglobin and deoxyhemoglobin, respectively (excluding the proportional coefficient). ε 1 (λi), ε 2 (λi) (i =
1, 2, 3) are the molecular extinction coefficients at each wavelength of oxyhemoglobin and deoxyhemoglobin, respectively. (A)
The difference from the equation is that there is no Δ mark indicating the amount of change before [HbO 2 ] and [HbO 2 ]. Also,
Since ε 1 (λi) and ε 2 (λi) in the equation (19) are absorption coefficients for a pure solution, literature values can be used, whereas the coefficients e 1 , e 2 , and e 3 , b 1 , b 2 , b 3
Has the inconvenience that must be determined by experiments on individual systems containing scattering components. Note that (1 / 2.303) in equation (19)
Is a conversion coefficient because the quantity on the left side is based on natural logarithm, whereas the molecular extinction coefficient on the right side is based on common logarithm.
【0038】(19)式は未知数が2つで式が3つであ
るから最小自乗法によって容易に解け、 〔HbO2〕=(1/2.303)〔k1・m(λ1)/f(λ1)+k2・m(λ2)/f(λ2)+k3・m(λ3)/f(λ 3 )〕 〔Hb〕 =(1/2.303)〔k1'・m(λ1)/f(λ1)+k2'・m(λ2)/f(λ2)+k3'・m(λ3)/f (λ3)〕 (20) となる。なお、散乱補正係数f(λ1),f(λ2),f(λ3)は
時間分解測定などで予め定めておく。これらの散乱補正
係数は波長によって大幅に変わることはなく、例えば以
下に示す780nm、805nm、830nmの場合、
それぞれf(780)=1.043,f(805)=1,f(830)=0.956とし
た。正確さは下がるが、この補正を省略し、全ての波長
でf(λ)=1としてもこの方法は原理的に成り立つ。な
お、(19),(20)式は2成分系だけでなく、測定
波長数を増やし、チトクロム・オキシダーゼや水を加え
た式とすることも可能である。Equation (19) has two unknowns and three equations.
Can be easily solved by the least squares method.Two) = (1 / 2.303) (k1・ M (λ1) / f (λ1) + kTwo・ M (λTwo) / f (λTwo) + kThree・ M (λThree) / f (λ Three )) (Hb) = (1 / 2.303) (k1'・ M (λ1) / f (λ1) + kTwo'・ M (λTwo) / f (λTwo) + kThree'・ M (λThree) / f (λThree)] (20). Note that the scattering correction coefficient f (λ1), F (λTwo), F (λThree) Is
It is determined in advance by time-resolved measurement or the like. These scattering corrections
The coefficients do not vary significantly with wavelength, for example
In the case of 780 nm, 805 nm, and 830 nm shown below,
F (780) = 1.043, f (805) = 1, f (830) = 0.956, respectively
Was. Accuracy is reduced, but this correction is omitted and all wavelengths are
Therefore, even if f (λ) = 1, this method is theoretically valid. What
The equations (19) and (20) are not limited to the two-component system, but are measured.
Increase the number of wavelengths and add cytochrome oxidase and water
It is also possible to use
【0039】以上のように、測定によって得られた各波
長のΔyから(18)式によって各波長でのmが求めら
れ、これを(20)式に代入すれば直ちにオキシヘモグ
ロビン量〔HbO2〕とデオキシヘモグロビン量〔H
b〕が求まる。このように、各測定成分iの成分濃度x
iを求めるために、本発明は、Δy=ln(I1/I2)を
求めるΔy算出手段と、その求められたΔyを用いてそ
の二次関数によるm(λ)(λは波長)を m(λ)=p・Δy2+q・Δy+r(p,q,rは係数) として求めるm(λ)算出手段と、各測定成分iの成分
濃度xi(i=1,2,……)を複数の波長λについて
のm(λ)を含む方程式の解として求める成分濃度算出手
段とを備えている。As described above, m at each wavelength is determined from the Δy of each wavelength obtained by the measurement according to the equation (18), and this is immediately substituted into the equation (20), whereby the amount of oxyhemoglobin [HbO 2 ] is immediately obtained. And the amount of deoxyhemoglobin [H
b] is obtained. Thus, the component concentration x of each measurement component i
In order to obtain i, the present invention uses Δy calculating means for obtaining Δy = ln (I 1 / I 2 ), and calculates m (λ) (λ is a wavelength) by a quadratic function using the obtained Δy. m (λ) = p · Δy 2 + q · Δy + r (where p, q and r are coefficients) and a component concentration xi (i = 1, 2,...) of each measurement component i A component concentration calculating means for obtaining a solution of an equation including m (λ) for a plurality of wavelengths λ.
【0040】[0040]
【実施例】図8は一実施例を表わす。レーザ装置3から
3波長のレーザ光λ1,λ2,λ3が切り換えて発振さ
れ、送光ファイバ4により被検体2に送られる。入射点
からa1(例えば10mm)とa2(例えば30mm)離
れたそれぞれの受光点で光を受光する受光用光ファイバ
8−1,8−2と送光ファイバ4がプローブ6により一
体として支持されており、被検体2に接触させられる。
受光用光ファイバ8−1と8−2はそれぞれの検出器1
0−1と10−2に導かれ、検出器10−1,10−2
の検出信号がそれぞれI1,I2となる。FIG. 8 shows an embodiment. Laser light λ 1 , λ 2 , and λ 3 of three wavelengths are switched and oscillated from the laser device 3 and sent to the subject 2 by the light transmitting fiber 4. The light-receiving optical fibers 8-1 and 8-2 for receiving light at respective light-receiving points a 1 (for example, 10 mm) and a 2 (for example, 30 mm) apart from the incident point and the light-transmitting fiber 4 are integrally supported by the probe 6. And is brought into contact with the subject 2.
The receiving optical fibers 8-1 and 8-2 are connected to the respective detectors 1.
0-1 and 10-2, the detectors 10-1, 10-2
Are I 1 and I 2 , respectively.
【0041】対数変換部12はそれらの検出信号I1,
I2を対数に変換するものである。図では自然対数ln
を示したが、常用対数logの場合でも、係数1/2.
303がかかるだけで、事実上同じである。μa・μ
s’演算部14はCPUにより実現され、図5に示され
るように、送受光部間距離a1とa2をパラメータとする
吸光度差Δyに対するB値の計算結果表を備えており、
一例としてa1=10mm、a2=30mmの場合は図5
の曲線Aを用いて、I1とI2から得られる吸光度差Δy
からBを算出し、さらにμa・μs’=B2/3からμa
・μs’を算出する。μa・μs’は各波長ごとに算出さ
れ、それらは表示部16に表示される。酸素化度、血液
量演算部18では、(13)式に与えられるような吸収
係数の比を算出したり、等吸収点でのμa・μs’から
血液量を算出する。The logarithmic converter 12 outputs the detection signals I 1 ,
And converts the I 2 in logarithm. In the figure, the natural logarithm ln
However, even in the case of a common logarithm log, the coefficient is 1/2.
It is virtually the same, only taking 303. μa ・ μ
The s ′ calculation unit 14 is realized by a CPU, and includes a calculation result table of the B value for the absorbance difference Δy using the distances a 1 and a 2 between the light transmission and reception units as parameters as shown in FIG.
As an example, when a 1 = 10 mm and a 2 = 30 mm, FIG.
Absorbance difference Δy obtained from I 1 and I 2 using curve A of
Calculating a B from further .mu.a from μa · μs' = B 2/ 3
・ Calculate μs ′. μa · μs ′ are calculated for each wavelength, and are displayed on the display unit 16. The oxygenation degree and blood volume calculation unit 18 calculates the ratio of the absorption coefficient as given by the equation (13), and calculates the blood volume from μa · μs ′ at the equal absorption point.
【0042】図9は他の実施例を表わしたものである。
図8のプローブ6を用いるのに代えてCCDカメラ20
のような面状検出器を用いている。22はCCD素子で
ある。この場合、送受光部間の距離aの連続関数として
(6)式又は図3に示されるy(a)のカーブが得られ
る。そのカーブに(6)式を合わせることにより、未知
数Bが求まる。a1とa2の2点だけでB値を求めるより
も、いっそう精度のよいB値を求めることができる。FIG. 9 shows another embodiment.
Instead of using the probe 6 of FIG.
Are used. 22 is a CCD element. In this case, a curve of y (a) shown in Expression (6) or FIG. 3 is obtained as a continuous function of the distance a between the light transmitting and receiving units. The unknown B is obtained by fitting the equation (6) to the curve. It is possible to obtain a more accurate B value than to obtain a B value using only two points a 1 and a 2 .
【0043】図10は各測定成分iの成分濃度xiまで
求めるようにした実施例の演算部分を示したものであ
る。図8と同様に対数変換部12で検出信号I1,I2が
対数に変換される。Δy算出手段30は対数変換された
検出信号I1,I2から Δy=ln(I1/I2) によりΔyを算出する。m(λ)算出手段32は求めら
れたΔyを用いてその二次関数によるm(λ)(λは波
長)を m(λ)=p・Δy2+q・Δy+r(p,q,rは係数) として求める。成分濃度算出手段34は、各測定成分i
の成分濃度xi(i=1,2,……)を複数の波長λに
ついてのm(λ)を含む方程式の解として求める。求めら
れた成分濃度は表示部36に表示される。図10で鎖線
で囲まれた手段30,32,34はCPUにより実現さ
れる。FIG. 10 shows the calculation part of the embodiment in which the component concentration xi of each measurement component i is obtained. As in FIG. 8, the logarithmic converter 12 converts the detection signals I 1 and I 2 into logarithms. The Δy calculating means 30 calculates Δy from the logarithmically converted detection signals I 1 and I 2 according to Δy = ln (I 1 / I 2 ). The m (λ) calculating means 32 uses the obtained Δy to calculate m (λ) (λ is a wavelength) by its quadratic function as follows: m (λ) = p · Δy 2 + q · Δy + r (p, q, r are coefficients ). The component concentration calculating means 34 calculates each measurement component i
Is determined as a solution of an equation including m (λ) for a plurality of wavelengths λ. The obtained component concentration is displayed on the display unit 36. The means 30, 32, and 34 surrounded by chain lines in FIG. 10 are realized by a CPU.
【0044】(18)式と(20)式を用いてオキシヘ
モグロビンとデオキシヘモグロビンの濃度を求め、さら
に酸素飽和度を求めた測定結果を図11に示す。図11
の測定では、腕にカフを巻きつけて、200mmHgの
圧力で動脈と静脈を止めた後の酸素状態の変化を780
nm、805nm、830nmの3波長で測定し、その
ときの各時刻におけるΔyの値から(18)式と(2
0)式を用いて各時刻のオキシヘモグロビンとデオキシ
ヘモグロビンの濃度値を求めたのが図11(A)であ
る。図の左端の矢印の時刻から200mmHgの圧力で
腕を締め、その後約450秒後に解除している。図11
(B)は酸素飽和度、すなわち(オキシヘモグロビンの
濃度値)/(オキシヘモグロビンとデオキシヘモグロビ
ンの濃度値の和)を酸素飽和度として示したものであ
る。The concentrations of oxyhemoglobin and deoxyhemoglobin were determined by using equations (18) and (20), and the results of measurement of the oxygen saturation are shown in FIG. FIG.
In the measurement, the cuff was wrapped around the arm, and the change in oxygen status after stopping the artery and vein at a pressure of 200 mmHg was measured at 780.
nm, 805 nm, and 830 nm, and from the value of Δy at each time at that time, Equation (18) and (2)
FIG. 11A shows the concentration values of oxyhemoglobin and deoxyhemoglobin at each time point using equation (0). The arm is tightened with a pressure of 200 mmHg from the time of the arrow at the left end of the figure, and then released about 450 seconds later. FIG.
(B) shows oxygen saturation, that is, (oxyhemoglobin concentration value) / (sum of oxyhemoglobin and deoxyhemoglobin concentration values) as oxygen saturation.
【0045】[0045]
【発明の効果】本発明では、定常光法で被検体上で測定
光の入射点から異なる距離だけ離れた複数の受光点で測
定光を受光することにより、吸収係数μaと等価散乱係
数μs’との積μa・μs’の絶対値を求めることがで
き、従来不可能であった定常光法による光学定数の絶対
測定が可能になる。従来は時間分解法であれば光学定数
の絶対測定の可能性はあるが、定常光法で絶対測定を行
なうものはない。その結果、本発明によれば、光学定数
の絶対測定を安価な定常光方式の装置で実現できる。さ
らに、本発明では従来からの懸案であった濃度の絶対値
を比例係数を除いて簡単な方法で得ることができる。さ
らに、分子吸光係数ε1(λi),ε2(λi)としては、個々
の散乱試料でなく、標準試料に対する値が使えるので、
客観性が高くなる。According to the present invention, the absorption coefficient μa and the equivalent scattering coefficient μs ′ are obtained by receiving the measurement light at a plurality of light receiving points separated from the incident point of the measurement light by different distances on the subject by the steady light method. And the absolute value of the product μa · μs ′ can be obtained, and the absolute measurement of the optical constant by the stationary light method, which has been impossible in the past, becomes possible. Conventionally, there is a possibility of absolute measurement of an optical constant by a time-resolved method, but there is no method for performing an absolute measurement by a stationary light method. As a result, according to the present invention, the absolute measurement of the optical constant can be realized with an inexpensive steady-light type apparatus. Further, in the present invention, the absolute value of the concentration, which has been a problem in the past, can be obtained by a simple method except for the proportionality coefficient. Furthermore, as the molecular extinction coefficients ε 1 (λi) and ε 2 (λi), values for a standard sample can be used instead of individual scattering samples.
Objectivity increases.
【図1】光散乱・吸収体におけるパルス光入射と出射を
示す図である。FIG. 1 is a diagram showing the incidence and emission of pulse light in a light scattering / absorbing body.
【図2】送受光部間距離を変えた場合のy(a)=lnR
(a,B)を示す図である。FIG. 2 shows y (a) = lnR when the distance between the light transmitting and receiving units is changed.
It is a figure showing (a, B).
【図3】送受光間部距離を変えた吸光度差測定からBを
求める方法を示す図である。FIG. 3 is a diagram showing a method of obtaining B from an absorbance difference measurement in which the distance between the transmitting and receiving portions is changed.
【図4】y=f(x)にしたときのx=Bを図上で求め
る方法を示す図である。FIG. 4 is a diagram showing a method for obtaining x = B on the figure when y = f (x).
【図5】吸光度差Δyに対するB値の計算結果を示す図
である。FIG. 5 is a diagram showing a calculation result of a B value with respect to an absorbance difference Δy.
【図6】被検体に対し1つの入射点と2つの受光点をも
つプローブによる測定を示す概略断面図である。FIG. 6 is a schematic cross-sectional view showing measurement by a probe having one incident point and two light receiving points with respect to a subject.
【図7】吸光度差Δyとμa・μs’の関係を示す図で
ある。FIG. 7 is a diagram showing the relationship between the absorbance difference Δy and μa · μs ′.
【図8】一実施例における光学系を概略断面図で示し、
演算部をブロック図で示す図である。FIG. 8 is a schematic cross-sectional view illustrating an optical system according to an embodiment;
FIG. 4 is a diagram illustrating a calculation unit in a block diagram.
【図9】他の実施例の光学系を示す概略断面図である。FIG. 9 is a schematic sectional view showing an optical system according to another embodiment.
【図10】成分濃度まで求める実施例の演算部分を示す
ブロック図である。FIG. 10 is a block diagram showing a calculation part of an embodiment for obtaining component concentrations.
【図11】(A)は腕締め時のオキシヘモグロビンとデ
オキシヘモグロビンの濃度値の測定例、(B)はそのと
きの酸素飽和度の測定例を示す図である。11A is a diagram illustrating an example of measuring the concentration values of oxyhemoglobin and deoxyhemoglobin when the arm is tightened, and FIG. 11B is a diagram illustrating an example of measuring the oxygen saturation at that time.
2 被検体 4 送光ファイバ 8−1,8−2 受光ファイバ 10−1,10−2 検出器 12 対数変換部 14 μa・μs’演算部 18 酸素化度・血液量演算部 20 CCDカメラ 30 Δy算出手段 32 m(λ)算出手段 34 成分濃度算出手段 2 Subject 4 Transmitting fiber 8-1, 8-2 Light receiving fiber 10-1, 10-2 Detector 12 Logarithmic conversion unit 14 μa · μs' calculation unit 18 Oxygenation degree / blood volume calculation unit 20 CCD camera 30 Δy Calculation means 32 m (λ) calculation means 34 Component concentration calculation means
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭46−5200(JP,A) 特開 平4−135547(JP,A) 特開 平5−52739(JP,A) 実開 平4−88909(JP,U) (58)調査した分野(Int.Cl.6,DB名) G01N 21/27 A61B 5/14 G01N 21/59──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-46-5200 (JP, A) JP-A-4-135547 (JP, A) JP-A-5-52739 (JP, A) 88909 (JP, U) (58) Fields investigated (Int. Cl. 6 , DB name) G01N 21/27 A61B 5/14 G01N 21/59
Claims (2)
検体上で前記測定光の入射点から異なる距離だけ離れた
複数の受光点で測定光を受光する測定光学系と、これら
複数の受光点で測定光を受光したときの各検出器の出力
を、送光点と受光点の距離aiの関数として測定した結
果をR(ai),i=1,2,3……(iは検出器の番
号)とするとき、これら検出器の個数だけの測定値R(a
i)に対し、理論式から予測されるパラメータB(=(3
μa・μs’)1/2)を含む関数R(ai,B)を等値し
て得られる連立方程式よりBを求め、これより積μa・
μs’を求める演算部を備えたことを特徴とする測定装
置。 ただし、μa;吸収係数 μs’=(1−g)μs; μs;散乱係数 g;散乱の非等方性パラメータ R(ai,B);測定値の予測関数で、Bをパラメータとする送受 光点間隔aiの関数であり、数表又は式で与えられるもの1. A measuring optical system which receives measuring light at a plurality of light receiving points separated by different distances from an incident point of the measuring light on the subject, wherein the measuring light is incident on a part of the subject. The result of measuring the output of each detector when the measurement light is received at a plurality of light receiving points as a function of the distance ai between the light transmitting point and the light receiving point is R (ai), i = 1, 2, 3,. When i is the number of detectors, the measured values R (a
i), the parameter B (= (3
μa · μs ′) 1/2 ), B is obtained from a simultaneous equation obtained by equalizing a function R (ai, B), and the product μa ·
A measurement device comprising a calculation unit for calculating μs ′. Here, μa; absorption coefficient μs ′ = (1−g) μs; μs; scattering coefficient g; anisotropic parameter of scattering R (ai, B); A function of the point spacing ai, given by a numerical table or equation
定光を入射し、その被検体上で前記測定光の入射点から
離れた受光点で測定光を受光するとともに、入射点と受
光点との距離を複数種類に異ならせるように入射点と受
光点のうちの一方が複数個設けられている測定光学系
と、受光点と入射点の1つの組における受光点と入射点
との距離をa1、その受光点での受光強度をI1とし、受
光点と入射点の他の組における受光点と入射点との距離
をa2、その受光点での受光強度をI2(I1>I2)とし
たとき、 Δy=ln(I1/I2)を求めるΔy算出手段と、 その求められたΔyを用いてその被検体の吸収係数に比
例する量m(λ)(λは波長)を二次関数 m(λ)=p・Δy2+q・Δy+r(p,q,rは係数) として求めるm(λ)算出手段と、 各測定成分iの成分濃度xi(i=1,2,……)を複
数の波長λについてのm(λ)を含む方程式の解として xi=kiλ1m(λ1)+kiλ2m(λ2)+kiλ3m(λ3)+…… =kiλ1(p・Δy2+q・Δy+r) +kiλ2(p・Δy2+q・Δy+r) +kiλ3(p・Δy2+q・Δy+r) +…… の形でxiを求める成分濃度算出手段と、を備えたこと
を特徴とする光学的測定装置。ただし、kiλ1,ki
λ2,kiλ3,……は各波長の重み、m(λ)の式の
p,q,rは送光点と受光点との距離に依存して定まる
定数である。2. A measuring light is incident on a part of a subject, which is a light scattering / absorbing body, and the measuring light is received on the subject at a light receiving point distant from an incident point of the measuring light. Optical system provided with a plurality of ones of the incident point and the light receiving point so as to make the distance between the light receiving point and the light receiving point different, and the light receiving point and the incident point in one set of the light receiving point and the incident point the distance between a 1, the received light intensity at the light receiving point and I 1, the received light intensity of the distance between the incident point and the receiving point in a 2, the receiving point in the other set of the incident point and receiving point I 2 (I 1 > I 2 ), Δy calculating means for obtaining Δy = ln (I 1 / I 2 ), and using the obtained Δy, an amount m (λ which is proportional to the absorption coefficient of the subject. ) (lambda is m (lambda) is calculated to obtain the wavelength) as a quadratic function m (λ) = p · Δy 2 + q · Δy + r (p, q, r are coefficients) And the component concentration xi (i = 1, 2,...) Of each measurement component i as a solution of an equation including m (λ) for a plurality of wavelengths λ xi = kiλ1m (λ1) + kiλ2m (λ2) + kiλ3m ( λ3) + ...... = kiλ1 (p · Δy 2 + q · Δy + r) + kiλ2 (p · Δy 2 + q · Δy + r) + kiλ3 (p · Δy 2 + q · Δy + r) + at ...... form of obtaining the xi component concentration calculation means and An optical measuring device comprising: Where kiλ1, ki
λ2, kiλ3,... are weights of respective wavelengths, and p, q, and r in the equation of m (λ) are constants determined depending on the distance between the light transmitting point and the light receiving point.
Priority Applications (1)
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JP6309719A JP2795197B2 (en) | 1994-04-30 | 1994-11-18 | Optical scattering / absorber measuring device |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP11423794 | 1994-04-30 | ||
JP6-114237 | 1994-04-30 | ||
JP6309719A JP2795197B2 (en) | 1994-04-30 | 1994-11-18 | Optical scattering / absorber measuring device |
Publications (2)
Publication Number | Publication Date |
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JPH0810244A JPH0810244A (en) | 1996-01-16 |
JP2795197B2 true JP2795197B2 (en) | 1998-09-10 |
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JP6309719A Expired - Fee Related JP2795197B2 (en) | 1994-04-30 | 1994-11-18 | Optical scattering / absorber measuring device |
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NL1012943C2 (en) * | 1999-08-31 | 2001-03-01 | Tno | Detector and imaging device for determining concentration ratios. |
CN1262235C (en) * | 2000-03-31 | 2006-07-05 | 皇家菲利浦电子有限公司 | Method and device for localizing deviant region in turbid medium |
JP4585553B2 (en) * | 2007-08-07 | 2010-11-24 | 日立オートモティブシステムズ株式会社 | apparatus |
JP5577757B2 (en) * | 2009-03-05 | 2014-08-27 | 横河電機株式会社 | Component measuring device |
JP6630061B2 (en) * | 2014-05-28 | 2020-01-15 | 天津先陽科技発展有限公司 | Method and apparatus for processing spread spectrum data |
DE102017106121B4 (en) * | 2017-03-22 | 2022-06-30 | Universität Hohenheim | Device and method for determining growth-relevant parameters in soil |
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JPH04135547A (en) * | 1990-07-02 | 1992-05-11 | Sumitomo Electric Ind Ltd | light sensor |
JPH0552739A (en) * | 1991-08-27 | 1993-03-02 | Sumitomo Electric Ind Ltd | Reflection spectrum measuring device |
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