JP2004081427A - Apparatus for measuring water content in living body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring a water content in a living body, which enables the water content in the living body to be rapidly and easily measured in a noninvasive manner by using near-infrared spectroscopy, so as to enable the grasp of the dynamics of the water content in the living body without causing a complication. <P>SOLUTION: This apparatus for measuring the water content in the living body is equipped with: a light-emitting and light-receiving means A which applies light, which includes a water-content correlation wavelength correlative to the water content in the living body in terms of absorbance of a near-infrared area and a fat correlation wavelength correlative to fat in the living body in terms of the absorbance of the near-infrared area, into the living body to be measured, so as to receive reflected light thereof or transmitted light thereof; and an in-living-body water content computing means 1 for determining the water content in the living body, in accordance with light reception information on the light with the water-content correlation wavelength and the light with the fat correlation wavelength, which are received by the means A, and in-living-body water content computing information for determining the water content in the living body from the light reception information. <P>COPYRIGHT: (C)2004,JPO

Description

【００２８】
【数４】
ここで、人体の含水率をα（　未知数）　とすると、
Ｍ_Ｂ＝αＷ_Ｂ
よって、

【００２９】
【数５】
式（７）に式（６）と式（８）を代入すると、

ここで、式（１）より、
ｆ（Ｓ_ＰＢ）−ｆ（Ｓ_ＰＡ）＝ｆ（Ｓ_ＰＢ−Ｓ_ＰＡ）−ｂ……………（１０）
式（９）、式（１０）より、
ｆ（Ｓ_ＰＢ−Ｓ_ＰＡ）＝（１−α）Ｗ_ＣＲ＋ｂ
【００３０】
以上より、腎不全患者の人工透析前後の体重変化率と差スペクトルとは線形関係で表されることが分かる。
【００３１】
そして、水分変化率推定式は、以下のようにして導出した。
複数の腎不全患者の透析前の原吸光度データ、透析後の原吸光度データをそれぞれを二次微分処理して、透析前の前処理吸光度データ、透析後の前処理吸光度データを求め、　（透析前の前処理吸光度データ）−（透析後の前処理吸光度データ）にて、人工透析前後の差スペクトルを求める。
又、複数の腎不全患者の透析前の体重値データ及び透析後の体重値データから、上記の式（４）により人工透析前後の体重変化率を求めると、その体重変化率を水分変化率とすることができる。
そして、上述のようにして求めた複数の腎不全患者の人工透析前後の差スペクトルと人工透析前後の水分変化率との関係を、重回帰分析、主成分回帰分析、ＰＬＳ回帰分析等により多変量解析し、下記の式（１１）の水分変化率Ｍｃを推定する水分変化率推定式を導出した。
【００３２】
【数６】
Ｍｃ＝ａ１×Ｓ_ＰＤλ_１＋ａ２×Ｓ_ＰＤλ_２＋ｃ……………（１１）
【００３３】
ここで、
λ１：水分相関波長、例えば９６０ｎｍ
ａ１：水分相関波長λ１の係数
Ｓ_ＰＤλ_１：水分相関波長λ１の人工透析前後の吸光度差
λ２：脂肪相関波長、例えば９１４ｎｍ
ａ２：脂肪相関波長λ２の係数
Ｓ_ＰＤλ_２：脂肪相関波長λ２の人工透析前後の吸光度差
ｃ：個人差補正項
【００３４】
つまり、生体内水分を計測するための特定波長として、水分相関波長λ１及び脂肪相関波長λ２を特定した。
【００３５】
次に、個人差を補正する補正項を導出する手法について説明する。
上記の式（１１）の水分変化率推定式に基づいて、健常者の水分指標値Ｉｎを導出する健常者水分指標値導出式を下記の式（１２）のように設定した。
【００３６】
【数７】
Ｉｎ＝ａ１×Ｓ_Ｐλ_１＋ａ２×Ｓ_Ｐλ_２……………（１２）
【００３７】
ここで、
ａ１：水分相関波長λ１の係数
Ｓ_Ｐλ_１：水分相関波長λ１（例えば、９６０ｎｍ）の吸光度
ａ２：脂肪相関波長λ２の係数
Ｓ_Ｐλ_２：脂肪相関波長λ２（例えば、９１４ｎｍ）の吸光度
【００３８】
そして、複数の健常者の原吸光度データを得ると共に、得た原吸光度データを二次微分処理して、前処理吸光度データを得て、上記の式（１２）の健常者水分指標値導出式により、複数の健常者の水分指標値Ｉｎを求める。
健常者の水分指標値Ｉｎは、略一定の値を示すはずであるから、上記の健常者の水分指標値Ｉｎが一定値１００になるように、補正項を追加する。
先ず、下記の式（１３）により、上記のように水分指標値を求めた各健常者の補正指標値Ｉｒを求める。
【００３９】
【数８】
Ｉｒ＝１００−Ｉｎ……………（１３）
【００４０】
そして、上述のように求めた複数の健常者の補正指標値Ｉｒと複数の健常者の原吸光度データを二次微分処理した前処理吸光度データとの関係を、重回帰分析、主成分回帰分析、ＰＬＳ回帰分析等により多変量解析し、下記の式（１４）のように補正指標値Ｉｒを推定する補正指標値推定式を導出した。
【００４１】
【数９】
Ｉｒ＝ａ３×Ｓ_Ｐλ_３＋ａ４×Ｓ_Ｐλ_４……………（１４）
【００４２】
ここで、
λ３：個体差減少波長、例えば８２０ｎｍ
ａ３：個体差減少波長λ３の係数
Ｓ_Ｐλ_３：個体差減少波長λ３の吸光度
λ４：個体差減少波長、例えば６７２ｎｍ
ａ４：個体差減少波長λ４の係数
Ｓ_Ｐλ_４：個体差減少波長λ４の吸光度
【００４３】
そして、上記の式（１２）の健常者水分指標値導出式と、式（１４）の補正指標値推定式により、生体内水分が正常な生体では同等の値となり、水分の増減により変化する水分指標値Ｉを推定するための水分指標値推定式として、下記の式（１５）を導出した。
【００４４】
【数１０】
Ｉ＝ａ１×Ｓ_Ｐλ_１＋ａ２×Ｓ_Ｐλ_２＋ａ３×Ｓ_Ｐλ_３＋ａ４×Ｓ_Ｐλ_４……………（１５）
【００４５】
ここで、
ａ１：水分相関波長λ１（例えば、９６０ｎｍ）の係数
Ｓ_Ｐλ_１：水分相関波長λ１の吸光度
ａ２：脂肪相関波長λ２（例えば、９１４ｎｍ）の係数
Ｓ_Ｐλ_２：脂肪相関波長λ２の吸光度
ａ３：個体差減少波長λ３（例えば、８２０ｎｍ）の係数
Ｓ_Ｐλ_３：個体差減少波長λ３の吸光度
ａ４：個体差減少波長λ４（例えば６７２ｎｍ）の係数
Ｓ_Ｐλ_４：個体差減少波長λ４の吸光度
つまり、個体差を減少させる特定波長として、個体差減少波長λ３及び個体差減少波長λ４を特定すると共に、水分相関波長λ１の光及び脂肪相関波長λ２の光の受光情報と個体差減少波長λ３、λ４から生体内水分として水分指標値を求めるための演算情報として上記式（１５）の水分指標値推定式を得た。ちなみに、個体差減少波長λ３としての８２０ｎｍは生体内の成分に影響されない波長であると考えられ、個体差減少波長λ４としての６７２ｎｍは、可視域であることから、皮膚及び生体組織内の色に関連する個体差を減少させるものであると考えられる。
【００４６】
上述のように導出した式（１５）にて示される水分指標値推定式を生体内水分検量式として、処理部１に記憶させてある。
そして、処理部１は、投受光手段Ａの受光情報であるアレイ型受光素子８からの出力情報、即ち、吸光度スペクトルを二次微分処理により前処理して、その前処理後の吸光度スペクトルに基づいて、内部に記憶している水分指標値推定式により、水分指標値を演算するように構成してある。
【００４７】
つまり、投受光手段Ａは、生体内の水分と吸光度において相関のある水分相関波長λ１、生体内の脂肪と吸光度において相関のある脂肪相関波長λ２、及び、個体差を減少させるための個体差減少波長λ３、λ４を含む光を計測対象生体内に照射して、その反射光を受光するように構成してある。
水分指標値推定式が生体内水分演算情報に相当し、その水分指標値推定式は、水分相関波長λ１の光及び脂肪相関波長λ２の光の受光情報と個体差減少波長λ３、λ４の光の受光情報とから、生体内水分が正常の生体では同等の値となり、水分の増減により変化する水分指標値を求める情報である。
そして、生体内水分演算手段としての処理部１は、投受光手段Ａにて受光された水分相関波長λ１の光、脂肪相関波長λ２の光、及び、個体差減少波長λ３、λ４の光の受光情報、並びに、生体内水分演算情報に相当する水分指標値推定式に基づいて、生体内水分として水分指標値を求めるように構成してある。
【００４８】
次に、上述のように構成した生体内水分測定装置で計測した水分指標値を評価した結果を説明する。
図５は、複数の男女の腎不全患者について人工透析前後に水分指標値を計測し、平均値と標準偏差についてプロットしたものである。図５中のＨＤ前が透析前、ＨＤ後が透析後をそれぞれ示している。
図５により、水分指標値は人工透析前後で人工透析後のほうが小さくなるように変化していることが分かるが、これは、人工透析により体内から過剰な水分がひかれるので人工透析後は人工透析前に比べて体内水分が少なくなることと一致している。
【００４９】
図６は、軽度の癌患者について外科手術を受ける前後に計測した水分指標値を、日毎に示したものであり、図７は、健常者について計測した水分指標値を、日毎に示したものであり、図６においては１例を、図２においては２例をそれぞれ示す。
図７により、健常者については、水分指標値の変化は、平均値から±３程度の範囲に収まっていることが分かる。一方、図６からは、外科手術を受けると、水分指標値は、手術中、手術後には、手術前から２０程度上昇し、容態が安定してきた時点（手術後２、３日）で、手術前のレベルに戻ることが分かる。
通常、外科的手術により体に侵襲が加えられると、血管内から細胞外への水分移動が増加し、その変化の程度は通常の変化の程度よりも大きく、又、一旦増加した水分は、手術後、数日経過すると手術前のレベルに戻ることが分かっているが、図６に示される結果は、このこととも一致する。
以上のことから、本発明の生体内水分測定装置によれば、生体内水分の適正な指標となる水分指標値を計測することができることが分かる。
【００５０】
又、上述のように、本発明の生体内水分測定装置により手術前後に水分指標値を計測した結果は、血管内から血管外の細胞に水分が流れ出すこと及び細胞内外液の水分バランスが崩れることに起因して、手術後は手術前よりも体内水分が多くなるという知見と一致していること、及び、本発明の生体内水分測定装置の検出体Ｓによれば、皮膚の表面からの深さが数ｍｍから１０ｍｍ程度の部位からの透過散乱光を受光できて、皮膚の表面からの深さが数ｍｍから１０ｍｍ程度の部位の体内水分に対応する情報を得ることができることから判断して、以下のことが分かる。
即ち、本発明の生体内水分測定装置によれば、侵襲が加えられたり体調が変化したりして生じる体内における細胞内外及び血管内から血管外の細胞への水分の移動を検出することができ、又、生体内水分として、血液中、細胞内及び細胞外に含まれる水分を計測することができる。
【００５１】
本発明の生体内水分測定装置により体内水分を計測するに当たって、体内水分の計測に適切な部位は、以下のようにして特定した。
人体各部における二次微分吸光度スペクトルデータを取得した結果、前腕部内側の肘に近い部分、二の腕内側、脹脛における二次微分吸光度スペクトルデータは、他の部位の二次微分吸光度スペクトルデータに比べて、水分相関波長λ１である９６０ｎｍ、及び、脂肪相関波長λ２である９１４ｎｍそれぞれにおいて、吸光度データを再現性良く計測できることが分かった。
従って、上述の如き人体各部における吸光度二次微分スペクトルの取得結果、及び、体内水分を計測する部位としては、安定してデータがとれ、筋肉組織の厚みが１０ｍｍ以上ある部位が適切であることを鑑みて、体内水分の計測に適切な部位として、前腕部内側の肘に近い部分、二の腕内側及び脹脛を特定した。
【００５２】
上述のように、本発明の生体内水分測定装置は、侵襲が加えられたり体調が変化したりして生じる体内における細胞内外及び血管内から血管外の細胞への水分の移動に対応して、体内水分を計測することができることから、本発明の生体内水分測定装置は、医療用として適切に使用することができる。
又、本発明の生体内水分測定装置の用途としては、上記の医療用の他に、一般家庭での健康管理、ダイエット中のモニター、運動時の水分補給の判断等、種々の用途で用いることが可能である。
即ち、体内水分量の変化は体調の変化や体型の変化につながることから、体内水分量を定期的に計測することにより、健康管理の目安とすることが可能となることから、本発明の生体内水分測定装置は、一般家庭での健康管理において用いることが可能である。
又、減量とは単に体重を減らすことではなく、余分な脂肪を減らすことであり、ダイエット中の体重減少が体内水分量の減少よりも大きい場合は、体脂肪を減少させていると考えられ、健康的にダイエットできていることとなる。そこで、本発明の生体内水分測定装置は、ダイエット中のモニターとして用いることが可能である。
又、運動開始時から体内水分を計測することにより、水分補給の目安とすることができるので、本発明の生体内水分測定装置は、運動時の水分補給の判断用として用いることが可能である。
【００５３】
〔別実施形態〕
次に別実施形態を説明する。
上述の実施形態においては、投受光手段Ａを、水分相関波長及び脂肪相関波長を含む光に加えて、個体差減少波長の光の受光情報を得るように構成し、生体内水分演算情報を、水分相関波長の光及び脂肪相関波長の光の受光情報と個体差減少波長の光の受光情報とから、生体内水分が正常の生体では同等の値となり、水分の増減により変化する水分指標値を求める情報とし、生体内水分演算手段１を、投受光手段Ａにて受光された水分相関波長の光、脂肪相関波長の光、及び、個体差減少波長の光の受光情報、並びに、生体内水分演算情報に基づいて、生体内水分として水分指標値を求めるように構成する場合について例示した。
これに代えて、投受光手段Ａを、水分相関波長及び脂肪相関波長を含む光を計測対象生体内に照射して、その反射光を受光するように構成し、生体内水分演算手段１を、投受光手段Ａにて受光された水分相関波長の光及び脂肪相関波長の光の受光情報、並びに、水分相関波長の光及び脂肪相関波長の光の受光情報から生体内水分を求める生体内水分演算情報に基づいて、生体内水分を求めるように構成しても良い。
この場合は、生体内水分演算情報として、水分相関波長λ１及び脂肪相関波長λ２を含む光を計測対象生体内に照射したときの水分相関波長λ１の光の吸光度及び脂肪相関波長λ２の光の吸光度により生体内水分を求めるための生体内水分検量式を設定する。
【００５４】
上記の実施形態においては、生体内水分検量式を設定するに当たっては、腎不全患者の人工透析前後の体重変化は略体内水分の変化であることに着目して、検量式設定用の生体の生体内水分に関連するデータとして、腎不全患者の人工透析前後の体重変化のデータを用いる場合について例示したが、検量式設定用の生体の生体内水分に関連するデータとしては、腎不全患者の人工透析前後の体重変化のデータの他に、インピーダンス法による生体内水分測定装置や重水を用いた生体内水分測定装置により計測した生体内水分量のデータを用いることができる。
【００５５】
上記の実施形態においては、生体内水分として、生体内水分が正常の生体では同等の値となり、水分の増減により変化する水分指標値を計測する場合について例示したが、生体内水分として、水分含有率や生体の単位重量当たりの水分含有重量等を計測するように構成しても良い。
【００５６】
上記の実施形態においては、人体の水分指標値を計測するに当たって、上記の式（１５）の如き１個の水分指標値推定式を設定したが、男女で体内水分に差があることから、水分指標値推定式を男女別に設定しても良い。あるいは、年齢別に設定しても良い。
【００５７】
水分相関波長λ１、脂肪相関波長λ２、個体差減少波長λ３、λ４の具体的な波長としては、上記の実施形態において例示した波長に限定されるものではなく、例えば、水分相関波長λ１、脂肪相関波長λ２、個体差減少波長λ３、λ４はそれぞれ、上記の実施形態において例示した波長を中心に、例えば、±１０ｎｍの範囲内で適正な波長に設定することが可能であり、又、前記の範囲外の波長にも設定することが可能である。
【００５８】
上記の実施形態においては、吸光度スペクトルを二次微分処理により前処理する場合について例示したが、この前処理としては、二次微分処理以外に、ＳＮＶ処理、ＭＳＣ処理等が可能である。又、前処理を省略することも可能である。
【００５９】
上記の実施形態においては、投受光手段Ａを、計測対象生体内に計測用光線を照射してその反射光を受光するように構成したが、例えば、照射部と受光部とを対向配置して、それら照射部と受光部との間に計測対象生体の計測部位を配置するようにし、計測対象生体内に計測用光線を照射してその透過光を受光するように構成しても良い。
又、投受光手段Ａは、水分相関波長の光のみ、脂肪相関波長の光のみ、個体差減少波長の光のみをそれぞれ透過させる複数のフィルタを備えさせたり、水分相関波長の光のみ、脂肪相関波長の光のみ、個体差減少波長の光のみをそれぞれ発光する複数の光源を備えさせたりして構成することが可能である。
【００６０】
本発明の生体内水分測定装置によれば、上記の実施形態において例示した人以外にも、動物、鳥類、魚類、植物等種々の生体の生体内水分を計測することが可能である。
【図面の簡単な説明】
【図１】実施形態にかかる生体内水分測定装置の全体概略構成を示す図
【図２】実施形態にかかる生体内水分測定装置により生体内水分を計測している状態を示す図
【図３】実施形態にかかる生体内水分測定装置の全体構成を示すブロック図
【図４】検出体の縦断面図
【図５】水分指標値の計測結果を示す図
【図６】水分指標値の計測結果を示す図
【図７】水分指標値の計測結果を示す図
【符号の説明】
１　　生体内水分演算手段
４　　光源
５　　照射部
６　　受光部
７　　分光部
８　　検出部
９ａ　照射用光ファイバー
９ｂ　受光用光ファイバー
Ａ　　投受光手段
Ｓ　　検出体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an in-vivo moisture measuring device for measuring the in-vivo moisture of a human body, an animal, or the like, and more particularly, to an in-vivo moisture measuring device capable of quickly and easily non-invasively measuring the in-vivo moisture.
[0002]
[Prior art]
Such an in-vivo moisture measuring device measures the in-vivo moisture of a living body such as a human, an animal, a plant, and the like. Water contained inside and outside the cell.
Conventionally, in medical practice, as a method of measuring the amount of water in the blood of the human body, a method of measuring the amount of water in the blood from the pressure of a catheter inserted into the central vein or the pulmonary artery is used, and such measurement was performed. The dynamics of the water content in the body was grasped from the water content in the blood.
Conventionally, as a method for measuring in-vivo moisture as the in-vivo moisture, there has been a method using an impedance method or a method using heavy water. BACKGROUND ART An in-vivo moisture measuring apparatus based on the impedance method is a device for measuring electric conductivity by passing weak electricity through a body and estimating the amount of water in the living body from the magnitude of the electric conductivity. In addition, in the in-vivo moisture measuring apparatus based on the impedance method, there is a device that uses a plurality of frequencies to improve the accuracy of measuring the in-vivo moisture. Incidentally, as the plurality of frequencies, for example, a frequency lower than 50 kHz for measuring the extracellular fluid and a frequency higher than 200 kHz for measuring the water content of the whole body including the inside of the cell are used.
In addition, an in-vivo moisture measuring device using heavy water is provided with heavy water to a subject, measures the total amount of heavy water in the breath for two hours, and estimates the in-vivo moisture amount based on the measured value. , Water is supplied to the sample, and two hours later, the degree of dilution of heavy water in the body is measured by NMR (nuclear magnetic resonance method), and the amount of water in the body is estimated based on the measured value.
[0003]
[Problems to be solved by the invention]
By the way, if you look closely at the water in the body, it is divided into extracellular fluid and intracellular fluid, and usually it comes and goes through blood vessels and intracellular walls, and the balance between intracellular fluid and extracellular fluid is kept constant .
However, when injured or ill, when invasive due to surgery, etc., or when an excessive infusion is performed, water flows out of the blood vessel to extracellular cells, and in addition, extracellular As the water moves, the water balance between the intracellular and extracellular fluids is disrupted, and the amount of intracellular, extracellular and intravascular water changes, resulting in an increase in body water. The water flowing out of the blood vessels is stored inside and outside the cells. In other words, water is stored in blood vessels, intracellularly and extracellularly, and after invasion, it returns mainly from extracellularly to blood vessels over several hours to several days (called a diuretic period). Will be excreted as urine.
[0004]
As described above, when injuries or illnesses occur, when invasion is caused by surgery, etc., or when excessive infusions are performed, body water increases. If the measurement can be carried out properly, appropriate treatment and treatment can be performed, and there is a demand for an in-vivo moisture measuring device capable of simply and quickly measuring non-invasive body water. To explain this point, in severely ill patients and post-operative patients, water in the blood vessels migrates to extravascular tissues, causing a change in the water balance in the whole body. The oxygen uptake ability at the cell level may be reduced. In particular, in patients with sepsis, heart failure, renal failure, etc., the dynamics of water content in the body have a profound effect on the disease state, and it is important to understand the dynamics of water content in the body in order to understand the transition of the disease state. There is a need for an in-vivo moisture measuring device that is indispensable for performing appropriate treatment, and that can easily and quickly measure non-invasive body water.
However, the method of measuring from the pressure of the catheter inserted into the central vein or the pulmonary artery only measures the amount of water in the blood vessel, and information on extravascular water, which accounts for most of the water content in the human body. Cannot be obtained, and water content in the body cannot be accurately measured. In addition, since it is necessary to insert a catheter into a large blood vessel, measurement cannot be easily performed anywhere, and there is a possibility that a complication mainly due to catheter infection may occur.
In addition, the in-vivo moisture measuring device using the impedance method has a problem in the accuracy of measuring the in-vivo moisture, and cannot be adequately applied for medical use.
In addition, the in-vivo moisture measurement device using heavy water has complicated operations related to the measurement of water content in the body, takes a long time to measure, and is not sufficiently adaptable for medical use. There was a problem of becoming expensive.
Therefore, when it is necessary to know the body water quickly, the degree of the body water has to be judged based on the experience, vision and touch of the doctor.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to quickly and easily use near-infrared spectroscopy in order to grasp the dynamics of body water without causing complications. It is an object of the present invention to provide an in-vivo moisture measuring device capable of non-invasively measuring in-vivo moisture.
[0006]
[Means for Solving the Problems]
[Invention of claim 1]
The in-vivo moisture measuring device according to claim 1 includes a moisture correlation wavelength correlated with moisture in the living body and an absorbance in the near infrared region and a fat correlation wavelength correlated with fat in the living body and an absorbance in the near infrared region. Irradiating light into the living body to be measured, and light emitting and receiving means for receiving the reflected light or transmitted light,
Obtain water in the living body from the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength received by the light emitting and receiving means, and the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength. An in-vivo water calculating means for obtaining in-vivo water based on in-vivo water calculation information.
That is, the light including the water correlation wavelength and the fat correlation wavelength is irradiated onto the living body to be measured by the light emitting and receiving means, and the reflected light or the transmitted light is received, and the in vivo moisture calculating means causes the light The in-vivo moisture is obtained based on the received light information of the received moisture-correlated wavelength light and fat-correlated wavelength light and the in-vivo moisture calculation information.
In other words, the inventors of the present invention have intensively studied to obtain a device that can quickly and easily measure non-invasive moisture in a living body, and irradiate light including a moisture correlation wavelength and a fat correlation wavelength to a living body to be measured. It has been found that the water content in a living body can be obtained based on the received light information of the reflected light or transmitted light.
Then, the light including the moisture correlation wavelength and the fat correlation wavelength is irradiated into the living body to be measured, and the light emitting and receiving means for receiving the reflected light or the transmitted light, and the light having the moisture correlation wavelength received by the light emitting and receiving means And light receiving information of light having a fat correlation wavelength, and, based on the in-vivo moisture calculation information, comprising in-vivo moisture calculating means for obtaining in-vivo moisture, so as to measure the in-vivo moisture by near-infrared spectroscopy. The obtained in-vivo moisture measuring device was obtained.
To add an explanation, fat is generally considered to be the next largest in water in water in the living body, so in determining the water content in the living body, in addition to the light reception information of the water correlation wavelength light, the fat correlation wavelength light It has been found that, if the in-vivo moisture is determined based on the received light information, the in-vivo moisture can be accurately measured by correcting individual differences.
In other words, the data relating to the in-vivo moisture of the living body for data acquisition and the absorbance data of the in-vivo living body for data acquisition are arithmetically processed, and as a specific wavelength for obtaining the in-vivo moisture, the degree and the absorbance of the in-vivo moisture are determined. A water correlation wavelength having correlation and a fat correlation wavelength for individual difference correction are obtained, and in vivo water calculation information for obtaining in vivo water from light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength is obtained. And, by irradiating the living body to be measured with light including the water correlation wavelength and the fat correlation wavelength by the light emitting and receiving means, and receiving the reflected light or transmitted light, and by the in vivo water calculating means, the light emitting and receiving means Based on the received information of the received light of the moisture correlation wavelength and the received light of the fat correlation wavelength, and the in-vivo moisture calculation information, the in-vivo moisture of the living body to be measured is determined. .
By the way, the moisture correlation wavelength and the fat correlation wavelength when measuring the moisture in the human body as the moisture in the living body, and the in vivo moisture calculation information for obtaining the in vivo moisture from the light reception information of the light of the moisture correlation wavelength and the light of the fat correlation wavelength. Is derived as follows.
That is, since the change in body weight before and after artificial dialysis of a patient with renal failure is considered to be a change in water in the body, it is considered as data related to the in-vivo water of the living body for data acquisition. We focused on the ability to use data on weight changes. Then, a plurality of artificial dialysis persons are irradiated with near-infrared rays before and after the dialysis treatment, respectively, before and after the dialysis treatment. The body weight data before dialysis treatment measured before and after the dialysis treatment of the dialyser, and the weight data after the dialysis treatment are processed, and the water correlation wavelength and fat correlation wavelength, and the water correlation wavelength are calculated. The in-vivo moisture calculation information for obtaining the in-vivo moisture from the light reception information of the light and the light having the fat correlation wavelength is derived.
Alternatively, using a conventional in-vivo moisture measuring device using an impedance method or a in-vivo moisture measuring device using heavy water, measure the water content of a plurality of subjects in the body and irradiate the subjects with near-infrared rays to measure spectral spectrum data. Then, the body water content data and the spectral spectrum data are arithmetically processed to obtain the water content in the living body from the water correlation wavelength and the fat correlation wavelength, and the light reception information of the water correlation wavelength light and the fat correlation wavelength light. Moisture calculation information can also be derived.
As described above, the in-vivo water can be measured using near-infrared spectroscopy, so that non-invasive measurement can be performed by simple operations such as irradiating the measurement target living body with measurement light using light emitting and receiving means. In addition, light receiving information can be quickly obtained by the light emitting / receiving means, and the received light information can be promptly processed by the in-vivo moisture calculating means constituted by the microcomputer, and the in-vivo water can be promptly calculated. It becomes possible to measure.
Incidentally, a case where the in-vivo moisture measuring device of claim 1 is used for medical purposes will be described.
According to the in-vivo moisture measuring device of the first aspect, it is possible to quickly and easily non-invasively measure the in-vivo moisture in the case of emergency such as injury or illness, or before and after surgery. Rather than relying on experience, sight and touch, it is possible to quantitatively measure water in the body, so that appropriate treatment and treatment can be performed, and it can be adequately adapted for medical use .
In short, in order to be able to grasp the dynamics of water in the body without causing complications, an in-vivo moisture measuring device that can quickly and easily measure non-invasive in-vivo moisture using near-infrared spectroscopy is provided. You can now.
[0007]
[Invention of claim 2]
According to a second aspect of the present invention, in the living body moisture measuring apparatus according to the first aspect, the light emitting and receiving unit irradiates the measurement target living body with light including an individual difference reducing wavelength for reducing an individual difference, and reflects the light. Configured to receive light or transmitted light,
The in-vivo moisture calculation information, from the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength and the light reception information of the light of the individual difference reduction wavelength, the same value in the living body where the water in the body is normal It is information for obtaining a moisture index value that changes due to an increase or decrease in moisture,
The in-vivo moisture calculating means receives the light of the moisture correlation wavelength, the light of the fat correlation wavelength, and the light of the individual difference decreasing wavelength received by the light emitting and receiving means, and the in-vivo moisture. It is characterized in that it is configured to calculate the water index value as the water in the living body based on the calculation information.
That is, in addition to the water correlation wavelength and the fat correlation wavelength, the light including the individual difference decreasing wavelength is radiated to the measurement target living body by the light emitting and receiving means, and the reflected light or transmitted light is received by the light The calculation information is based on the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength and the light reception information of the light with the individual difference reduction wavelength, and the water in the living body has the same value in a normal living body, and changes according to the increase and decrease of the water. The moisture index value is set as information to be obtained, and, by the in-vivo moisture calculating means, the light of the moisture correlation wavelength received by the light receiving means, the light of the fat correlation wavelength, and the light reception information of the light of the individual difference reduction wavelength, In addition, a water index value is obtained as the water content in the living body based on the water content calculation information.
That is, in addition to the light reception information of the light having the water correlation wavelength and the light having the fat correlation wavelength, the in-vivo moisture is obtained by the light reception information of the light having the individual difference reduction wavelength, so that the in vivo Moisture can be accurately determined.
Moreover, as the in-vivo water, the in-vivo water has the same value in a normal living body, and by calculating a water index value that changes due to an increase or decrease in water, for example, the obtained water index value is calculated as It can be easily compared with the moisture index value in the normal case, and it can be easily determined whether the in-vivo moisture is appropriate or inappropriate.
Accordingly, it has become possible to measure the water content in the living body with high accuracy regardless of the individual difference, and furthermore, it is possible to easily determine whether the water content in the living body is appropriate or inappropriate.
[0008]
[Invention of claim 3]
The light source according to claim 2, wherein the light emitting and receiving means emits light in a band including the water correlation wavelength, the fat correlation wavelength, and the individual difference reduction wavelength. And an irradiating unit for irradiating the living body with light from the light source, a light receiving unit for receiving a reflected light or a transmitted light of the light irradiated from the irradiating unit, and a light receiving unit for each of the light receiving units. It is characterized by comprising a spectroscopic unit for splitting light and a detecting unit for detecting the intensity of the split light.
That is, light from the light source emits light in a band including the moisture correlation wavelength, the fat correlation wavelength, and the individual difference reduction wavelength, the light from the light source is irradiated into the living body by the irradiation unit, and the light is irradiated from the irradiation unit by the light receiving unit. The reflected light or transmitted light of the received light is received, the light received by the light receiving unit is separated by the wavelength separating unit, and the intensity of the light separated by the wavelength is detected by the detecting unit by the detecting unit. Is done.
In other words, in measuring water in the living body using at least three wavelengths of the water correlation wavelength, the fat correlation wavelength, and the individual difference reduction wavelength, only the water correlation wavelength light, only the fat correlation wavelength light, and the individual difference A plurality of filters that respectively transmit only the reduced wavelength light are provided, or a plurality of light sources that respectively emit only the moisture correlation wavelength light, the fat correlation wavelength only, and the individual difference reduction wavelength are provided. However, compared to them, as described above, the light in the band including the moisture correlation wavelength, the fat correlation wavelength, and the individual difference reduction wavelength is irradiated into the living body to be measured, and the reflected light or the transmitted light is received. Then, the received reflected light or transmitted light is dispersed to detect the light intensity for each wavelength, so that the number of parts can be reduced and the optical system can be simplified. Configuration It is possible to simplify.
Accordingly, the configuration of the light emitting and receiving means can be simplified, and the cost can be further reduced.
[0009]
[Invention of claim 4]
The in-vivo moisture measuring device according to claim 4, wherein, in claim 3, the irradiation unit and the light receiving unit are provided in a state where the irradiation unit is formed in a ring shape when viewed in the irradiation direction of the irradiation unit, and It is configured as a detector provided with a light receiving unit in a state located inside the irradiation unit,
An irradiation optical fiber that guides light from the light source to the irradiation unit and a light reception optical fiber that guides light from the light receiving unit to the spectroscopic unit are connected to the detection body.
That is, light from the light source is guided to the irradiating section by the irradiating optical fiber, is radiated from the annular irradiating section to the living body to be measured, and reflected light from within the living body to be measured is received by the light receiving section. The received light is guided to the light splitting unit by the light receiving optical fiber.
That is, the detection body is configured to include the irradiation unit and the light receiving unit, and the detection body is connected to the light source by an irradiation optical fiber that can be provided with flexibility, and also provided with flexibility. By connecting the light-receiving optical fiber to the spectroscopy unit, the light source and the light-splitting unit, which are easy to increase in size and weight, are fixed, and the detector is placed in the living body of the living body to be measured. In order to measure moisture, it can be arranged at any position.
Further, as the detection body, the irradiation unit and the light receiving unit may be provided in a state where the irradiation unit is formed in an annular shape and the light receiving unit is positioned inward of the irradiation unit when viewed in the irradiation direction of the irradiation unit. By irradiating the optical fiber for light irradiation and light receiving by connecting the light source for guiding the light from the light source to the irradiating part and the light receiving optical fiber for guiding the light from the light receiving part to the spectroscopic part to the detection body. While making the diameter of the optical fiber small, it is possible to make the irradiation part larger in diameter than the irradiation optical fiber connected to it, so that the distance between the annular irradiation part and the light receiving part located on the inner side thereof is widened. It becomes possible. Since the distance between the irradiation unit and the light receiving unit can be increased, it is possible to receive reflected light from a position as deep as possible in the living body to be measured. In other words, while reducing the diameters of the irradiation optical fiber and the light receiving optical fiber so that they are excellent in operability, it is possible to receive reflected light reflected inside the living body to be measured, that is, so-called diffuse reflected light, at the light receiving unit. This makes it possible to appropriately obtain information relating to the in-vivo moisture of the living body to be measured.
Therefore, it has become possible to more appropriately measure the water content in the living body while improving the operability.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a case will be described in which the in-vivo moisture measuring device is applied for measuring the in-vivo moisture of a human body.
As shown in FIG. 3, the in-vivo moisture measuring device irradiates measurement light to the inside of a subject as a living body to be measured, and transmits and receives the reflected light. In-vivo for obtaining the in-vivo water as the in-vivo moisture based on the received light information received and the calibration equation for measuring the in-vivo moisture stored in the body (hereinafter sometimes abbreviated as the in-vivo moisture calibration equation) The apparatus includes a processing unit 1 as a moisture calculating means, a display unit 2 for displaying the body water determined by the processing unit 1, and a power supply unit 3 for driving the apparatus including a battery.
The light emitting / receiving means A receives a light source 4 that emits light for measurement, an irradiating unit 5 that irradiates the light from the light source 4 into the body of the subject, and receives reflected light of the light emitted from the irradiating unit 5. A light receiving unit 6, a light separating unit 7 that separates the light received by the light receiving unit 6 for each wavelength, and an array light receiving element 8 as a detecting unit that detects the intensity of the separated light I have.
[0011]
In addition, the irradiation unit 5 and the light receiving unit 6 are provided in a state where the irradiation unit 5 is formed in a ring shape when viewed in the irradiation direction of the irradiation unit 5, and the light receiving unit 6 is provided in a state where the light receiving unit 6 is located inside the irradiation unit 5. An irradiation optical fiber 9a for guiding light from the light source 4 to the irradiation unit 4 and a light receiving optical fiber 9b for guiding light from the light receiving unit 6 to the spectroscopic unit 7 are connected to the detection object S. It is.
[0012]
As shown in FIGS. 1 and 3, the processing unit 1, the display unit 2, the power supply unit 3, and the light source 4, the spectroscopic unit 7, and the array-type light receiving element 8 that constitute the light emitting / receiving unit A use a main casing 10. The irradiation optical fiber 9a and the light receiving optical fiber 9b are coaxial and flexible such that the light receiving optical fiber 9b is located inside the annular irradiation optical fiber 9a. To form a measurement probe 9.
Then, the detection body S and the main body M, which are configured to be separate from each other as described above, are connected by a flexible measurement probe 9, and as shown in FIG. Is held in hand and applied to a predetermined part of the subject (for example, a portion near the elbow inside the forearm) to measure the water content in the body of the subject.
[0013]
Hereinafter, each part constituting the in-vivo moisture measuring apparatus will be described.
As shown in FIG. 3, the light source 4 includes a tungsten-halogen lamp 4a that emits light in a near-infrared wavelength range including a wavelength range of 600 to 1000 nm, and an optical device that cuts off heat generated from the tungsten-halogen lamp 4a. It is composed of a filter (not shown). By the way, near-infrared light in the wavelength range of 600 to 1000 nm is suitable for non-invasively measuring body water because it has strong penetration into the human body and does not involve heat generation.
[0014]
As described above, the measurement probe 9 includes the irradiation optical fiber 9a and the light receiving optical fiber 9b except for the light incident end side of the irradiation optical fiber 9a and the light emitting end side of the light receiving optical fiber 9b. It is formed coaxially, and at the coaxial end surface, the annular end surface of the irradiation optical fiber 9a and the circular end surface of the light receiving optical fiber 9b inside it are flush.
[0015]
As shown in FIG. 4, the detection body S is formed by assembling an inner cylinder body 12 and an outer cylinder body 13 held coaxially in a state of being separated by a connecting member 11 in a detection body casing 14, A probe connecting cylinder 15 is externally fitted to the base end of the body 13, and a probe mounting screw 16 is screwed into the mounting cylinder 15. The tip of the measuring probe 9 is inserted into the probe connecting cylinder 15. Then, the measurement probe 9 and the detection object S are connected by tightening the probe mounting screw 16.
[0016]
The inner cylindrical body 12 is formed in a generally frusto-conical shape in which the inner diameter and the outer diameter of the cylinder become smaller as approaching the probe connecting portion on the base end side, and the thickness of the peripheral wall becomes smaller as approaching the base end side. Further, the inner cylindrical body 12 has an inner diameter substantially the same as the diameter of the circular distal end surface of the light receiving optical fiber 9b at the fiber connection portion on the base end side, and the thickness of the peripheral wall is set to the light receiving optical fiber 9b. Of the optical fiber 9a for irradiation is substantially equal to the distance between the distal end surface of the optical fiber 9a for irradiation. The inner peripheral surface and the outer peripheral surface of the inner cylindrical body 12 are finished to mirror surfaces capable of reflecting light. Note that an optical fiber for guiding light may be inserted into the inner cylinder 12.
The outer cylinder 13 is formed in a generally frusto-conical shape in which the inner diameter and the outer diameter of the cylinder become smaller as the diameter approaches the fiber connection portion on the base end side. In the portion, the inner diameter is substantially the same as the outer diameter of the annular distal end surface of the light receiving optical fiber 9a. The inner peripheral surface of the outer cylinder 13 is finished to a mirror surface capable of reflecting light.
[0017]
Then, an annular opening formed by the distal end of the inner cylindrical body 12 and the distal end of the outer cylindrical body 13 functions as the irradiation section 5, and the distal opening of the inner cylindrical body 12 functions as the light receiving section 6. The shape of the opening of the fiber connection portion on the proximal end side of the inner cylindrical body 12 becomes substantially the same as the shape of the distal end surface of the optical fiber 9b for light reception, and the base end of the inner cylindrical body 12 and the outer cylindrical body 13 The shape of the annular opening formed by the base end is substantially the same as the shape of the annular distal end surface of the irradiation optical fiber 9a.
That is, when the detection body S is connected to the distal end of the measurement probe 9, the opening of the inner cylindrical body 12 is located in a state of facing the distal end surface of the optical fiber 9b for light reception, and the inner cylindrical body 12 and the outer cylindrical body 13 Is formed so as to be located in a state of facing the annular distal end surface of the irradiation optical fiber 9a.
[0018]
Therefore, the measuring light beam from the light source 4 guided by the irradiation optical fiber 9a enters the space between the inner cylinder 12 and the outer cylinder 13 from the distal end surface of the irradiation optical fiber 9a, and And emitted from an annular irradiator 5 formed by the distal end of the inner cylindrical body 12 and the distal end of the outer cylindrical body 13 to irradiate the body of the subject. The light is received by the light receiving unit 6 functioning at the opening of the distal end of the inner cylindrical body 12, and the received light passes through the inner cylindrical body 12 and is emitted to the distal end surface of the light receiving optical fiber 9b. The light is guided to the light splitting unit 7 by the light receiving optical fiber 9b.
[0019]
As described above, by configuring the detection body S and connecting it to the tip of the measurement probe 9, the irradiation unit 5 and the light reception unit 6 can be connected to each other while reducing the diameters of the irradiation optical fiber 9a and the light receiving optical fiber 9b. Can be widened, the transmitted scattered light from the body of the subject can be received, and the moisture in the body of the subject can be measured.
[0020]
As shown in FIG. 3, the light splitting unit 7 is configured such that the light (reflected light from the subject) guided by the light-receiving optical fiber 9 b enters the dark box 7 b into which the light is guided from the entrance hole 7 a through the entrance hole 7 a. And a concave diffraction grating 7d that spectrally reflects the light reflected by the reflecting mirror 7c.
[0021]
The array-type light receiving element 8 simultaneously receives the light of each wavelength spectrally reflected by the concave diffraction grating 7d for each wavelength, and outputs a signal corresponding to the light flux intensity for each wavelength.
[0022]
The processing unit 1 is configured using a microcomputer. Basically, the light receiving information of the light emitting / receiving means A, that is, the output information from the array type light receiving element 8 and the in-vivo data stored inside It is configured to calculate the body water based on the water calibration formula.
[0023]
Hereinafter, a setting method of the in-vivo moisture meter calibration formula will be described.
The change in body weight of patients with renal insufficiency before and after dialysis is considered to be approximately the change in body water, and the rate of change in body weight of patients with renal insufficiency before and after dialysis and the difference spectrum of absorbance before and after dialysis are linearly related. Therefore, in the present embodiment, first, a water change rate estimation formula for estimating the water change rate is derived from the weight change rate before and after the artificial dialysis of the renal failure patient and the difference spectrum, and then the individual difference By deriving a correction term for correcting the above, and by adding the correction term to the above-mentioned moisture change rate estimation formula, a moisture index value estimation formula for estimating a moisture index value as body water is derived, and the moisture index value estimation formula is obtained. Was defined as the in-vivo moisture calibration formula.
[0024]
First, the point that the weight change rate before and after the artificial dialysis of a renal failure patient and the difference spectrum are represented by a linear relationship will be described.
The change in weight seen before and after dialysis in an dialysis patient is caused by drawing excess water in the body by dialysis, so that the change in weight before and after dialysis corresponds to the change in water in the body.
The absorbance at the time of irradiating the subject's body with the measuring light beam is S_P, And the equation for estimating the in-vivo moisture is_P), The absorbance S at a specific wavelength λ according to Beer-Lambert's law._Pλ is represented in the form of a linear polynomial.
[0025]
(Equation 1)
f (S_P) = A₁S_Pλ₁+ A₂S_Pλ₂… + A_nS_Pλ_n+ B ... (1)
Where a_nIs a coefficient, b is a constant including 0
Absorbance spectrum before dialysis_PB, Weight W_B, The weight of water is M_BThen
f (S_PB) = M_B/ W_B............ (2)
Absorbance spectrum after dialysis_PA, Weight W_A, The weight of water is M_AThen
f (S_PA) = M_A/ W_A............ (3)
[0026]
(Equation 2)
Weight change rate W_CRIs
W_CR= (W_B-W_A) / W_A............ (4)
Here, if the change in body weight before and after dialysis is only a change in body water,
W_B-W_A= M_B-M_A............ (5)
Substituting equation (5) into equation (4) gives
W_CR= (M_B-M_A) / W_A............ (6)
[0027]
(Equation 3)
The difference between the spectra before and after the artificial dialysis, that is, Equation (2) -Equation (3) is represented by the following Equation (7).

[0028]
(Equation 4)
Here, assuming that the moisture content of the human body is α ({unknown number)},
M_B= ΑW_B
Therefore,

[0029]
(Equation 5)
Substituting equations (6) and (8) into equation (7) gives

Here, from equation (1),
f (S_PB) -F (S_PA) = F (S_PB-S_PA) -B ... (10)
From equations (9) and (10),
f (S_PB-S_PA) = (1−α) W_CR+ B
[0030]
From the above, it can be seen that the weight change rate before and after the artificial dialysis of the renal failure patient and the difference spectrum are represented by a linear relationship.
[0031]
Then, the moisture change rate estimation formula was derived as follows.
The original absorbance data before dialysis and the original absorbance data after dialysis of a plurality of patients with renal insufficiency are subjected to second derivative processing to obtain the pretreatment absorbance data before dialysis and the pretreatment absorbance data after dialysis. The difference spectrum before and after artificial dialysis is determined by (pretreatment absorbance data of (1))-(pretreatment absorbance data after dialysis).
From the weight value data before and after dialysis of a plurality of patients with renal insufficiency, the weight change rate before and after artificial dialysis is calculated by the above equation (4), and the weight change rate is defined as the water change rate. can do.
Then, the relationship between the difference spectrum before and after artificial dialysis of a plurality of patients with renal failure and the rate of change in water before and after artificial dialysis obtained as described above was multivariately analyzed by multiple regression analysis, principal component regression analysis, PLS regression analysis, and the like. An analysis was performed to derive a moisture change rate estimation formula for estimating the moisture change rate Mc of the following equation (11).
[0032]
(Equation 6)
Mc = a1 × S_PDλ₁+ A2 × S_PDλ₂+ C ... (11)
[0033]
here,
λ1: moisture correlation wavelength, for example, 960 nm
a1: coefficient of moisture correlation wavelength λ1
S_PDλ₁: Absorbance difference before and after artificial dialysis at water correlation wavelength λ1
λ2: fat correlation wavelength, for example, 914 nm
a2: coefficient of fat correlation wavelength λ2
S_PDλ₂: Absorbance difference before and after artificial dialysis of fat correlation wavelength λ2
c: Individual difference correction term
[0034]
That is, the moisture correlation wavelength λ1 and the fat correlation wavelength λ2 were specified as the specific wavelengths for measuring the water content in the living body.
[0035]
Next, a method for deriving a correction term for correcting individual differences will be described.
Based on the moisture change rate estimating equation of the above equation (11), a healthy person moisture index value deriving equation for deriving a healthy person moisture index value In was set as the following equation (12).
[0036]
(Equation 7)
In = a1 × S_Pλ₁+ A2 × S_Pλ₂............ (12)
[0037]
here,
a1: coefficient of moisture correlation wavelength λ1
S_Pλ₁: Absorbance at moisture correlation wavelength λ1 (for example, 960 nm)
a2: coefficient of fat correlation wavelength λ2
S_Pλ₂: Absorbance at fat correlation wavelength λ2 (for example, 914 nm)
[0038]
Then, while obtaining the original absorbance data of a plurality of healthy subjects, the obtained original absorbance data is subjected to a second derivative process to obtain pre-processed absorbance data, and the water index value of the healthy subject is derived by the above formula (12). , The water index values In of a plurality of healthy persons are obtained.
Since the water index value In of a healthy person should show a substantially constant value, a correction term is added so that the water index value In of a healthy person becomes a constant value 100.
First, the correction index value Ir of each healthy person whose moisture index value has been obtained as described above is obtained by the following equation (13).
[0039]
(Equation 8)
Ir = 100-In (13)
[0040]
Then, the relationship between the corrected index values Ir of the plurality of healthy subjects obtained as described above and the pre-processed absorbance data obtained by subjecting the original absorbance data of the plurality of healthy subjects to the second derivative processing, a multiple regression analysis, a principal component regression analysis, A multivariate analysis was performed by PLS regression analysis or the like, and a correction index value estimation equation for estimating the correction index value Ir was derived as in the following equation (14).
[0041]
(Equation 9)
Ir = a3 × S_Pλ₃+ A4 × S_Pλ₄............ (14)
[0042]
here,
λ3: wavelength for decreasing individual difference, for example, 820 nm
a3: Coefficient of individual difference reduction wavelength λ3
S_Pλ₃: Absorbance at wavelength λ3 at which individual difference decreases
λ4: wavelength for decreasing individual difference, for example, 672 nm
a4: Coefficient of individual difference reduction wavelength λ4
S_Pλ₄: Absorbance at wavelength λ4 for decreasing individual difference
[0043]
Then, according to the above-described formula (12) for deriving a healthy person moisture index value and the correction index value estimating formula (14), the water content in the living body becomes the same value in a normal living body, and the water content changes as the water content increases or decreases. The following equation (15) was derived as a moisture index value estimation equation for estimating the index value I.
[0044]
(Equation 10)
I = a1 × S_Pλ₁+ A2 × S_Pλ₂+ A3 × S_Pλ₃+ A4 × S_Pλ₄............ (15)
[0045]
here,
a1: Coefficient of moisture correlation wavelength λ1 (for example, 960 nm)
S_Pλ₁: Absorbance at moisture correlation wavelength λ1
a2: Coefficient of fat correlation wavelength λ2 (for example, 914 nm)
S_Pλ₂: Absorbance at fat correlation wavelength λ2
a3: coefficient of individual difference reduction wavelength λ3 (for example, 820 nm)
S_Pλ₃: Absorbance at wavelength λ3 at which individual difference decreases
a4: coefficient of individual difference reduction wavelength λ4 (for example, 672 nm)
S_Pλ₄: Absorbance at wavelength λ4 for decreasing individual difference
That is, the individual difference reduction wavelength λ3 and the individual difference reduction wavelength λ4 are specified as the specific wavelength for reducing the individual difference, and the light reception information of the light of the water correlation wavelength λ1 and the light of the fat correlation wavelength λ2 and the individual difference reduction wavelength λ3, From the λ4, a water index value estimating equation of the above equation (15) was obtained as calculation information for obtaining a water index value as water in the living body. Incidentally, 820 nm as the individual difference reduction wavelength λ3 is considered to be a wavelength that is not affected by the components in the living body, and 672 nm as the individual difference reduction wavelength λ4 is in the visible range, so that the color in the skin and the biological tissue is It is thought to reduce related individual differences.
[0046]
The processing unit 1 stores the moisture index value estimating equation represented by the equation (15) derived as described above as the in vivo moisture calibration equation.
Then, the processing unit 1 pre-processes the output information from the array type light receiving element 8 which is the light receiving information of the light emitting and receiving means A, that is, the absorbance spectrum by the second derivative processing, and based on the absorbance spectrum after the pre-processing. In addition, the apparatus is configured to calculate the moisture index value using the moisture index value estimation formula stored therein.
[0047]
That is, the light emitting / receiving means A is provided with a water correlation wavelength λ1 having a correlation with the moisture in the living body and a fat correlation wavelength λ2 having a correlation with the fat in the living body, and an individual difference reduction for reducing the individual difference. The light having the wavelengths λ3 and λ4 is irradiated into the living body to be measured, and the reflected light is received.
The moisture index value estimating formula corresponds to the in-vivo moisture calculation information, and the moisture index value estimating formula is the light receiving information of the light of the moisture correlation wavelength λ1 and the light of the fat correlation wavelength λ2 and the light of the individual difference decreasing wavelengths λ3, λ4. Based on the received light information, it is information for obtaining a water index value that is equivalent in a normal living body and changes with an increase or decrease of the water based on the received light information.
Then, the processing unit 1 as the in-vivo moisture calculating means receives the light of the moisture correlation wavelength λ1, the light of the fat correlation wavelength λ2, and the light of the individual difference decreasing wavelengths λ3, λ4 received by the light emitting / receiving means A. It is configured to obtain a water index value as the water in the living body based on the information and the water index value estimating formula corresponding to the water calculating information in the living body.
[0048]
Next, the result of evaluating the water index value measured by the in-vivo water measuring device configured as described above will be described.
FIG. 5 is a graph in which water index values are measured before and after artificial dialysis for a plurality of male and female renal failure patients, and the average value and the standard deviation are plotted. In FIG. 5, before HD, before dialysis and after HD, after dialysis, respectively.
FIG. 5 shows that the water index value before and after the artificial dialysis is changed so that it becomes smaller after the artificial dialysis. This is consistent with the fact that the body water is lower than before the dialysis.
[0049]
FIG. 6 shows the water index values measured before and after surgery for mild cancer patients on a daily basis, and FIG. 7 shows the water index values measured on a healthy person for each day. FIG. 6 shows one example, and FIG. 2 shows two examples.
From FIG. 7, it can be seen that the change in the water index value of a healthy person falls within a range of about ± 3 from the average value. On the other hand, from FIG. 6, when a surgical operation is performed, the water index value increases during the operation and after the operation by about 20 from before the operation, and when the condition becomes stable (two or three days after the operation), You can see that it returns to the previous level.
Usually, when the body is invaded by a surgical operation, the movement of water from the blood vessel to the outside of the cell increases, and the degree of the change is larger than the normal degree of change. It is known that a few days later, the level returns to the level before the operation, but the result shown in FIG. 6 is consistent with this.
From the above, it is understood that the in-vivo moisture measuring apparatus of the present invention can measure a moisture index value that is an appropriate index of in-vivo moisture.
[0050]
Further, as described above, the result of measuring the water index value before and after the operation by the in-vivo water measuring device of the present invention indicates that water flows out of the blood vessel to extracellular cells and that the water balance of the intracellular and extracellular fluids is disrupted. Is consistent with the finding that the body water becomes larger after surgery than before surgery, and according to the detection body S of the in-vivo moisture measurement device of the present invention, the depth from the surface of the skin Judging from the fact that it can receive transmitted and scattered light from a site with a depth of about several mm to 10 mm and can obtain information corresponding to body water at a site with a depth of several mm to about 10 mm from the surface of the skin The following can be understood.
That is, according to the in-vivo moisture measuring device of the present invention, it is possible to detect the movement of moisture from inside and outside the cell and inside the blood vessel to the outside blood vessel from the inside and outside of the body caused by invasion or physical condition change. In addition, water contained in blood, inside cells and outside cells can be measured as water in a living body.
[0051]
In measuring the body water with the in-vivo water measuring device of the present invention, a site suitable for measuring the body water was specified as follows.
As a result of obtaining the second derivative absorbance spectrum data in each part of the human body, the second derivative absorbance spectrum data in the part near the elbow inside the forearm, the inside of the second arm, the calf is compared with the second derivative absorbance spectrum data in other parts, It was found that absorbance data can be measured with good reproducibility at each of 960 nm, which is a water correlation wavelength λ1, and 914 nm, which is a fat correlation wavelength λ2.
Therefore, as described above, the results of acquisition of the second derivative spectrum of absorbance in each part of the human body, and as a site for measuring water in the body, stable data can be obtained, and a site having a muscle tissue thickness of 10 mm or more is appropriate. In view of this, the portion near the elbow inside the forearm, the inside of the upper arm, and the calf were specified as appropriate sites for the measurement of body water.
[0052]
As described above, the in-vivo moisture measurement device of the present invention responds to the movement of water from intracellular and extracellular in the body and from intravascular to extracellular cells caused by invasion or changes in physical condition, Since the body water can be measured, the in-vivo water measurement device of the present invention can be appropriately used for medical purposes.
In addition to the above-mentioned medical use, the in-vivo moisture measuring device of the present invention may be used for various purposes such as health management in a general household, monitoring during a diet, determination of hydration during exercise, and the like. Is possible.
That is, since the change in the amount of water in the body leads to a change in the physical condition and the shape of the body, it is possible to measure the amount of water in the body periodically to use it as a guide for health management. The body moisture measuring device can be used for health care at home.
Also, weight loss is not simply to lose weight, it is to reduce excess fat, and if weight loss during diet is greater than decrease in body water content, it is considered that body fat is reduced, You will be on a healthy diet. Therefore, the in-vivo moisture measuring device of the present invention can be used as a monitor during dieting.
In addition, by measuring body water from the start of exercise, it can be used as a guide for hydration, so the in-vivo moisture measurement device of the present invention can be used for determining hydration during exercise. .
[0053]
[Another embodiment]
Next, another embodiment will be described.
In the above embodiment, in addition to the light including the water correlation wavelength and the fat correlation wavelength, the light emitting and receiving means A is configured to obtain light reception information of the light having the individual difference reduction wavelength, From the received light information of the light of the water correlation wavelength and the light of the fat correlated wavelength and the received light information of the light of the individual difference decreasing wavelength, the water index value that changes in accordance with the increase and decrease of the water becomes the same value in the normal living body. As the information to be sought, the in-vivo moisture calculating means 1 transmits the received light information of the light of the moisture correlation wavelength, the light of the fat correlation wavelength, and the light of the wavelength with reduced individual difference received by the light emitting / receiving means A, and the in-vivo moisture. An example has been described in which the configuration is such that a moisture index value is determined as the moisture in the living body based on the calculation information.
Instead of this, the light emitting / receiving means A is configured to irradiate light including the moisture correlation wavelength and the fat correlation wavelength into the living body to be measured, and to receive the reflected light thereof. In-vivo moisture calculation for obtaining in-vivo moisture from received light information of the moisture-correlated wavelength light and fat-correlated wavelength light received by the light emitting / receiving means A, and received light information of the moisture-correlated wavelength light and the fat-correlated wavelength light You may comprise so that the living body moisture may be calculated | required based on information.
In this case, the absorbance of the light of the moisture correlation wavelength λ1 and the absorbance of the light of the fat correlation wavelength λ2 when light including the moisture correlation wavelength λ1 and the fat correlation wavelength λ2 is irradiated into the measurement target body as the moisture calculation information in the living body. To set the in-vivo moisture calibration formula for obtaining the in-vivo moisture.
[0054]
In the above embodiment, in setting the in-vivo water calibration formula, focusing on the fact that a change in body weight of a patient with renal insufficiency before and after dialysis is substantially a change in body water, a living body for the calibration formula setting is focused on. As the data relating to the body water, the case of using the data of the weight change before and after the artificial dialysis of the renal failure patient is illustrated, but the data relating to the body water of the living body for the calibration formula setting is the artificial renal failure patient. In addition to the data on body weight change before and after dialysis, data on the amount of water in the living body measured by an in-vivo water measuring device using an impedance method or an in-vivo water measuring device using heavy water can be used.
[0055]
In the above embodiment, as the in-vivo moisture, the case where the in-vivo moisture has the same value in a normal living body and a moisture index value that changes due to increase and decrease of the moisture is measured, It may be configured to measure the rate, the water-containing weight per unit weight of the living body, and the like.
[0056]
In the above embodiment, when measuring the water index value of the human body, a single water index value estimation formula such as the above equation (15) is set. The index value estimation formula may be set for each gender. Alternatively, it may be set for each age.
[0057]
Specific wavelengths of the moisture correlation wavelength λ1, the fat correlation wavelength λ2, and the individual difference reduction wavelengths λ3 and λ4 are not limited to the wavelengths exemplified in the above embodiment. The wavelength λ2 and the individual difference reduction wavelengths λ3 and λ4 can be set to appropriate wavelengths within a range of ± 10 nm, for example, around the wavelength exemplified in the above-described embodiment. It is possible to set it to an outside wavelength.
[0058]
In the above-described embodiment, the case where the absorbance spectrum is pre-processed by the second derivative processing has been exemplified. However, as the pre-process, an SNV process, an MSC process, or the like can be used in addition to the second derivative process. Further, the pre-processing can be omitted.
[0059]
In the above embodiment, the light emitting / receiving means A is configured to irradiate the measuring light beam into the measurement target living body and receive the reflected light. Alternatively, the measurement site of the living body to be measured may be arranged between the irradiating unit and the light receiving unit, and the measuring light may be radiated into the living body to be measured to receive the transmitted light.
Further, the light emitting / receiving means A is provided with a plurality of filters that respectively transmit only the light having the water correlation wavelength, the light having the fat correlation wavelength, and the light having the individual difference decreasing wavelength. It is also possible to provide a plurality of light sources that emit only the light of the wavelength and the light of the individual difference reduction wavelength, respectively.
[0060]
According to the in-vivo moisture measuring apparatus of the present invention, it is possible to measure the in-vivo moisture of various living organisms such as animals, birds, fish, plants, etc., in addition to the person exemplified in the above embodiment.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall schematic configuration of an in-vivo moisture measuring device according to an embodiment.
FIG. 2 is a diagram showing a state in which the in-vivo moisture is measured by the in-vivo moisture measuring apparatus according to the embodiment;
FIG. 3 is a block diagram showing the overall configuration of the in-vivo moisture measuring device according to the embodiment;
FIG. 4 is a longitudinal sectional view of a detection object.
FIG. 5 is a diagram showing a measurement result of a moisture index value.
FIG. 6 is a diagram showing a measurement result of a moisture index value.
FIG. 7 is a diagram showing a measurement result of a moisture index value.
[Explanation of symbols]
1 Means for calculating moisture in living body
4 Light source
5 mm irradiation unit
6 Light receiving section
7 Spectroscopic unit
8 Detector
9a Optical fiber for irradiation
9b Optical fiber for receiving light
A Emitting and receiving means
S object

Claims (4)

A light containing a water correlation wavelength that is correlated with the absorbance in the near infrared region with moisture in the living body and a fat correlation wavelength that is correlated with the absorbance in the near infrared region with fat in the living body is irradiated onto the living body to be measured, and its reflection is performed. Light emitting and receiving means for receiving light or transmitted light,
Obtain water in the living body from the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength received by the light emitting and receiving means, and the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength. An in-vivo moisture measuring device comprising: in-vivo moisture calculating means for obtaining in-vivo moisture based on in-vivo moisture calculation information. The light emitting and receiving means is configured to irradiate the measurement target living body with light including an individual difference reduction wavelength for reducing individual differences, and to receive reflected light or transmitted light thereof,
The in-vivo moisture calculation information, from the light reception information of the light of the water correlation wavelength and the light of the fat correlation wavelength and the light reception information of the light of the individual difference reduction wavelength, the same value in the living body where the water in the body is normal It is information for obtaining a moisture index value that changes due to an increase or decrease in moisture,
The in-vivo moisture calculating means receives the light of the moisture correlation wavelength, the light of the fat correlation wavelength, and the light of the individual difference decreasing wavelength received by the light emitting and receiving means, and the in-vivo moisture. The in-vivo moisture measuring device according to claim 1, wherein the in-vivo moisture measuring device is configured to obtain the moisture index value as in-vivo moisture based on the calculation information. The light emitting and receiving means, the light source that emits light in the band including the moisture correlation wavelength, the fat correlation wavelength, and the individual difference reduction wavelength, and an irradiation unit that irradiates light from the light source into a living body, A light receiving unit that receives reflected light or transmitted light of light emitted from the irradiation unit, a light separating unit that separates the light received by the light receiving unit for each wavelength, and a detection that detects the intensity of the separated light The in-vivo moisture measuring device according to claim 2, further comprising a unit. Detection in which the irradiating unit and the light receiving unit are provided in a state where the irradiating unit is formed in a ring shape and the light receiving unit is provided in a state positioned on the inner side of the irradiating unit when viewed in the irradiation direction of the irradiating unit. Composed as a body,
The in-vivo water according to claim 3, wherein an irradiation optical fiber that guides light from the light source to the irradiation unit, and a light reception optical fiber that guides light from the light receiving unit to the light splitting unit are connected to the detection body. measuring device.

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