JP5298703B2 - Sweat measurement method - Google Patents
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- 210000004243 sweat Anatomy 0.000 title claims description 56
- 238000000691 measurement method Methods 0.000 title 1
- 210000000106 sweat gland Anatomy 0.000 claims description 64
- 230000035900 sweating Effects 0.000 claims description 62
- 238000000034 method Methods 0.000 claims description 19
- 230000008859 change Effects 0.000 claims description 13
- 239000011148 porous material Substances 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 230000003340 mental effect Effects 0.000 claims description 8
- 230000002123 temporal effect Effects 0.000 claims description 2
- 210000004907 gland Anatomy 0.000 claims 1
- 230000003287 optical effect Effects 0.000 description 32
- 238000005259 measurement Methods 0.000 description 28
- 210000003491 skin Anatomy 0.000 description 17
- 239000013307 optical fiber Substances 0.000 description 10
- 230000035945 sensitivity Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000000638 stimulation Effects 0.000 description 5
- 239000002775 capsule Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 210000004207 dermis Anatomy 0.000 description 3
- 210000005036 nerve Anatomy 0.000 description 3
- 230000000284 resting effect Effects 0.000 description 3
- 230000002889 sympathetic effect Effects 0.000 description 3
- 102000008186 Collagen Human genes 0.000 description 2
- 108010035532 Collagen Proteins 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 2
- KXNLCSXBJCPWGL-UHFFFAOYSA-N [Ga].[As].[In] Chemical compound [Ga].[As].[In] KXNLCSXBJCPWGL-UHFFFAOYSA-N 0.000 description 2
- 229920001436 collagen Polymers 0.000 description 2
- 210000002615 epidermis Anatomy 0.000 description 2
- 210000001519 tissue Anatomy 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- 210000004556 brain Anatomy 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
- Measuring And Recording Apparatus For Diagnosis (AREA)
Description
本発明は、被験者の手掌部に分布するエクリン汗腺の発汗量を高感度で測定する方法に関する。 The present invention relates to how to measure the amount of perspiration of eccrine sweat glands distributed in the palm of the subject with high sensitivity.
従来の発汗計は、所定面積の開口を有するカプセルを手掌や指先に密着させた状態で、乾燥空気をカプセル内部空間に供給し、発汗による相対湿度の増加を計測することによって、皮膚表面から外部に放出された発汗量を推定している（例えば、下記特許文献１，２）。カプセルの開口面積を１ｃｍ２に設定した場合、ここにヒト指先では数百のエクリン汗腺が包含されることになる。従って、得られる測定値は、各エクリン汗腺からの発汗量の合計値となる。 A conventional perspiration meter supplies dry air to the capsule internal space in a state where a capsule having an opening of a predetermined area is in close contact with the palm or fingertip, and measures the increase in relative humidity due to perspiration. The amount of perspiration released into the body is estimated (for example, Patent Documents 1 and 2 below). When the opening area of the capsule is set to 1 cm 2 , several hundred eccrine sweat glands are included in the human fingertip. Accordingly, the measured value obtained is the total value of the sweating amount from each eccrine sweat gland.
従来の発汗計では、汗腺の汗孔から外部に放出された水分量のみを測定対象としているため、発汗量の多い温熱性発汗についてはかなり精度よく測定できる。しかしながら、発汗量が極めて微量な精神性発汗や味覚性発汗については充分な感度が得られていない。
また、一定の開口面積に包含される多数の汗腺を合算して測定しているため、汗腺ごとの個体差に関する情報は全く得られない。
In the conventional sweat meter, only the amount of water released to the outside from the sweat pores of the sweat glands is measured, and therefore, thermal sweat with a large amount of sweat can be measured with considerably high accuracy. However, sufficient sensitivity has not been obtained for mental sweating and taste sweating in which the amount of sweating is extremely small.
In addition, since a large number of sweat glands included in a certain opening area are combined and measured, no information on individual differences for each sweat gland can be obtained.
本発明の目的は、特定のエクリン汗腺についての発汗量を高感度で測定できる発汗量測定方法を提供することである。 An object of the present invention is to provide a sweat amount measuring how capable of measuring the amount of perspiration for a particular eccrine sweat glands with high sensitivity.
上記目的を達成するために、本発明に係る発汗量測定方法は、被験者の手掌部に分布する特定のエクリン汗腺における発汗量を測定する方法であって、
ＯＣＴ画像を解析することにより、エクリン汗腺の汗孔が閉じた状態で特定のエクリン汗腺内部に存在する水分の信号強度の積算値に基づいて特定のエクリン発汗量を測定するステップを含むことを特徴とする。
In order to achieve the above object, the method for measuring the amount of sweating according to the present invention is a method for measuring the amount of sweating in a specific eccrine sweat gland distributed in the palm of the subject,
Analyzing the OCT image, and measuring a specific amount of eccrine perspiration based on an integrated value of the signal intensity of water present in the specific eccrine sweat gland with the sweat pores of the eccrine sweat gland closed. And
本発明において、エクリン汗腺の汗孔が開いた状態で汗腺内部に存在する発汗量を測定するステップをさらに含むことが好ましい。 In the present invention, it is preferable that the method further includes the step of measuring the amount of perspiration present in the sweat gland with the sweat pores of the eccrine sweat gland open.
本発明において、汗腺内部および外部に存在する総発汗量を測定するステップをさらに含むことが好ましい。 In the present invention, it is preferable that the method further includes the step of measuring the total amount of sweat present inside and outside the sweat glands.
本発明において、被験者に外部刺激を与えた時点からの発汗量の時間変化を計測することが好ましい。 In the present invention, it is preferable to measure a temporal change in the amount of sweating from the time when an external stimulus is applied to the subject.
本発明において、外部刺激は、音刺激または握力負荷などの精神性あるいは物理的ストレスであることが好ましい。 In the present invention, the external stimulus is preferably a mental or physical stress such as a sound stimulus or a grip force load.
本発明によれば、特定のエクリン汗腺についての発汗量を高感度で測定することができる。そのため、従来の発汗計では測定が難しい精神性発汗や味覚性発汗などに起因した発汗状態を広い測定レンジで測定できる。 According to the present invention, can it to measure the amount of perspiration for a particular eccrine sweat glands with high sensitivity. Therefore, it is possible to measure a sweating state caused by mental sweating or taste sweating, which is difficult to measure with a conventional sweat meter, in a wide measurement range.
図１は、ＯＣＴ計測を用いた発汗量測定装置の一例を示す構成図である。ＯＣＴ計測部１０は、低コヒーレンス光源を用いたマイケルソン干渉計として構成され、スーパールミネッセントダイオード(ＳＬＤ：Super-luminescent diode)光源１１と、単一モードの光ファイバカプラ１２と、光位相変調器１３，１６と、照射部１４と、参照光ミラー１７と、光検出器１８と、単一モードの光ファイバからなる光路Ｌ１，Ｌ２，Ｌ３，Ｌ４などを備える。 FIG. 1 is a configuration diagram illustrating an example of a sweating amount measuring apparatus using OCT measurement. The OCT measurement unit 10 is configured as a Michelson interferometer using a low-coherence light source, and includes a super luminescent diode (SLD) light source 11, a single mode optical fiber coupler 12, and an optical phase modulation. Units 13 and 16, an irradiation unit 14, a reference light mirror 17, a photodetector 18, and optical paths L 1, L 2, L 3, and L 4 made of a single mode optical fiber.
ＳＬＤ光源１１は、例えば、中心波長が１．３μｍ、発振スペクトル幅が約５０ｎｍの低コヒーレンス光を発生する。ＳＬＤ光源１１からの光は、光路Ｌ１を通って光ファイバカプラ１２に到達する。光ファイバカプラ１２は、光路Ｌ１からの光を光路Ｌ２，Ｌ３に向けて所定の比率で分岐する。光路Ｌ２に分岐された光は、照射部１４へ到達する。 The SLD light source 11 generates, for example, low coherence light having a center wavelength of 1.3 μm and an oscillation spectrum width of about 50 nm. The light from the SLD light source 11 reaches the optical fiber coupler 12 through the optical path L1. The optical fiber coupler 12 branches the light from the optical path L1 toward the optical paths L2 and L3 at a predetermined ratio. The light branched into the optical path L2 reaches the irradiation unit 14.
照射部１４は、集光用のレンズ、走査用のガルバノミラー５１などを備え、光路Ｌ２からの光を被験者の皮膚（例えば、指の掌面）に向けて照射する。皮膚の内部構造に応じて反射した信号光が、照射部１４に再び入射し、光路Ｌ２を逆行して光ファイバカプラ１２に戻る。 The irradiation unit 14 includes a condensing lens, a scanning galvanometer mirror 51, and the like, and irradiates light from the optical path L2 toward the skin of the subject (for example, the palm of the finger). The signal light reflected according to the internal structure of the skin is incident on the irradiating unit 14 again, travels back along the optical path L2, and returns to the optical fiber coupler 12.
一方、光ファイバカプラ１２によって光路Ｌ３に分岐された光は、参照光ミラー１７で反射すると、光路Ｌ３を逆行して光ファイバカプラ１２に戻る。 On the other hand, when the light branched to the optical path L3 by the optical fiber coupler 12 is reflected by the reference light mirror 17, the light travels backward through the optical path L3 and returns to the optical fiber coupler 12.
光路Ｌ２の途中には光位相変調器１３が設けられ、光路Ｌ３の途中には光位相変調器１６が設けられ、タイムドメインＯＣＴ（ＴＤ―ＯＣＴ）光学系を構成している。光位相変調器１３，１６は、印加電圧に応じて光路長を変化させて、光の位相を変調する機能を有し、例えば、円筒状（例えば、外径５０ｍｍ、高さ４０ｍｍ）の圧電アクチュエータの外周に光ファイバを約２０ｍ巻回して構成される。圧電アクチュエータの両端には、ファンクションジェネレータ２５からの駆動電圧Ｖ１，Ｖ２が印加される。駆動電圧Ｖ１，Ｖ２は、例えば、最大値が＋２５０Ｖ、最小値が−２５０Ｖの三角波電圧で、互いに逆相の関係にある。従って、光位相変調器１３，１６は、互いに逆相で動作するプッシュプル方式で駆動される。光位相変調器１３，１６を±２５０Ｖの三角波電圧で駆動した場合、光軸方向（生体の深さ方向）の走査距離は約２．５ｍｍである。 An optical phase modulator 13 is provided in the middle of the optical path L2, and an optical phase modulator 16 is provided in the middle of the optical path L3 to constitute a time domain OCT (TD-OCT) optical system. The optical phase modulators 13 and 16 have a function of modulating the optical phase by changing the optical path length in accordance with the applied voltage. For example, the piezoelectric actuator has a cylindrical shape (for example, an outer diameter of 50 mm and a height of 40 mm). An optical fiber is wound about 20 m around the outer periphery of the lens. Drive voltages V1 and V2 from the function generator 25 are applied to both ends of the piezoelectric actuator. The drive voltages V1 and V2 are triangular wave voltages having a maximum value of +250 V and a minimum value of −250 V, for example, and are in a phase relationship with each other. Therefore, the optical phase modulators 13 and 16 are driven by a push-pull method that operates in mutually opposite phases. When the optical phase modulators 13 and 16 are driven with a triangular wave voltage of ± 250 V, the scanning distance in the optical axis direction (the depth direction of the living body) is about 2.5 mm.
光路Ｌ２，Ｌ３をそれぞれ逆行した光は、光ファイバカプラ１２で混合されて干渉光を発生する。干渉光は、光路Ｌ４を通って光検出器１８に到達する。光検出器１８は、例えば、インジウムガリウムヒ素（ＩｎＧａＡｓ）のＰＩＮダイオードで構成され、干渉光の強度に応じた電圧をヘテロダインビート信号として出力する。 The light traveling backward in the optical paths L2 and L3 is mixed by the optical fiber coupler 12 to generate interference light. The interference light reaches the photodetector 18 through the optical path L4. The photodetector 18 is composed of, for example, an indium gallium arsenide (InGaAs) PIN diode, and outputs a voltage corresponding to the intensity of the interference light as a heterodyne beat signal.
光検出器１８からの信号は、増幅器２０を経由してフィルタ２１に入力される。フィルタ２１は、所要の周波数帯域の信号のみを透過するバンドパスフィルタとして構成され、ノイズを除去する機能を有する。フィルタ２１からの信号は、広帯域増幅器２２を経由してＡ／Ｄ変換器２３に入力される。Ａ／Ｄ変換器２３は、入力信号を、例えば、１２ビットのデジタル信号へ変換して、信号処理部５０へ出力する。 A signal from the photodetector 18 is input to the filter 21 via the amplifier 20. The filter 21 is configured as a band-pass filter that transmits only a signal in a required frequency band, and has a function of removing noise. The signal from the filter 21 is input to the A / D converter 23 via the broadband amplifier 22. The A / D converter 23 converts the input signal into, for example, a 12-bit digital signal and outputs it to the signal processing unit 50.
信号処理部５０は、例えば、パーソナルコンピュータで構成され、Ａ／Ｄ変換器２３からのデジタル信号を保存して各種の演算処理を実行するとともに、ファンクションジェネレータ２５の動作、照射部１４におけるガルバノミラーの動作、装置全体の動作などを制御する。 The signal processing unit 50 is constituted by, for example, a personal computer, stores a digital signal from the A / D converter 23 and executes various arithmetic processes, operates the function generator 25, and operates the galvano mirror in the irradiation unit 14. Controls the operation and the operation of the entire device.
照射部１４には、ＯＣＴ光学系の光軸に介在するビームスプリッタ３０と、撮像素子３１とが設けられる。撮像素子３１は、例えば、ＣＣＤカメラで構成され、ＯＣＴ走査領域を含む汗腺画像を取得する。撮像素子３１からの映像信号は、画像モニター３２に送られ、スクリーン上に汗腺画像として表示されるとともに、フレームグラバー３３に保存される。保存された画像データは、必要に応じて信号処理部５０へ伝送される。 The irradiation unit 14 is provided with a beam splitter 30 interposed on the optical axis of the OCT optical system and an image sensor 31. The image sensor 31 is configured by a CCD camera, for example, and acquires a sweat gland image including an OCT scanning region. The video signal from the image sensor 31 is sent to the image monitor 32, displayed as a sweat gland image on the screen, and stored in the frame grabber 33. The stored image data is transmitted to the signal processing unit 50 as necessary.
撮像素子３１が装着された照射部１４は、光学系の光軸方向の位置を調整するためのｚステージ４４と、光軸方向に垂直な方向の位置を調整するためのｘｙステージ４３に搭載されている。一方、照射部１４の下方には、被験者の指を保持するためのサンプルホルダ４７と、サンプルホルダ４７の光軸回り角度を調整するためのθステージ４６と、θステージ４６を戴置する固定台４８とが設置される。ｘｙステージ４３、ｚステージ４４およびθステージ４６は、ステージドライバー４２に電気接続されており、Ｄ／Ａ変換器４１を介して信号処理部５０によって制御される。 The irradiation unit 14 to which the image sensor 31 is mounted is mounted on a z stage 44 for adjusting the position of the optical system in the optical axis direction and an xy stage 43 for adjusting the position in the direction perpendicular to the optical axis direction. ing. On the other hand, below the irradiation unit 14, a sample holder 47 for holding the subject's finger, a θ stage 46 for adjusting the angle around the optical axis of the sample holder 47, and a fixed base on which the θ stage 46 is placed. 48 are installed. The xy stage 43, the z stage 44 and the θ stage 46 are electrically connected to the stage driver 42, and are controlled by the signal processing unit 50 via the D / A converter 41.
図２は、測定部位を示す説明図である。図２（ａ）に示すように、指の掌面には指紋と汗孔が分布しており、この汗孔に通ずる汗腺ダクトが表皮から真皮まで延びている。図２（ｂ）は、汗孔を通る断面に沿ったＯＣＴ画像である。横方向が皮膚の深さ方向を示しており、縦に延びる皮膚から汗腺ダクトがスパイラル状に延びて、汗腺ダクト内に存在する水分の反射画像がスパイラル状に現れている。汗腺ダクトの末端より下方には、コラーゲンの反射像が分布している。 FIG. 2 is an explanatory diagram showing measurement sites. As shown in FIG. 2A, fingerprints and sweat holes are distributed on the palm surface of the finger, and a sweat gland duct communicating with the sweat holes extends from the epidermis to the dermis. FIG. 2B is an OCT image along a cross section passing through the sweat pores. The horizontal direction indicates the depth direction of the skin, and the sweat gland duct extends spirally from the vertically extending skin, and a reflection image of moisture existing in the sweat gland duct appears spirally. A reflected image of collagen is distributed below the end of the sweat gland duct.
皮膚組織の屈折率は約１．４であるのに対して、水の屈折率は１．３３であるため、光が皮膚の深さ方向に進行すると、両者の屈折率差による界面反射が生ずる。ＴＤ−ＯＣＴでは、信号光および参照光の位相変調によって深さ方向に沿った断層画像が得られる。汗腺の水分量が多くなると、信号強度もほぼ比例して増加することから、汗孔付近および汗腺ダクト内部に存在する画像のみを抽出し、その信号強度を積分することにより、特定の汗腺における発汗量を正確に見積もることができる。 The refractive index of skin tissue is about 1.4, whereas the refractive index of water is 1.33. Therefore, when light travels in the depth direction of the skin, interface reflection occurs due to the difference in refractive index between the two. . In TD-OCT, a tomographic image along the depth direction is obtained by phase modulation of signal light and reference light. As the amount of water in the sweat gland increases, the signal intensity also increases almost proportionally. Therefore, by extracting only the images near the sweat pores and inside the sweat gland duct and integrating the signal intensity, sweating in a specific sweat gland The amount can be estimated accurately.
本実施形態では、被験部位である指先汗腺のダイナミックＯＣＴ画像を取得している。測定条件として、１枚のＯＣＴデータ取得時間は０．２秒、イメージサイズは１ｍｍ×１ｍｍ、フレーム間隔は１秒、約５分間（３００秒）連続的に汗腺のＯＣＴ画像を取得する。精神性発汗のストレスとして刺激音を聞かせ、皮膚交感神経に関わる発汗を促進し、ダイナミックＯＣＴで観察する。刺激音として、被験者に、例えば、ガラスが割れたときの不快音（音量９０ｄＢ、持続時間０．５秒）を聞かせた場合、この音に反応して指先の発汗が促進される。交感神経が正常である場合、音刺激を与えると発汗が促され、ＯＣＴ画像上で汗腺の信号強度が大きく増大する。なお、音刺激の代わりに握力負荷を与えるようにしても構わない。 In this embodiment, a dynamic OCT image of a fingertip sweat gland that is a test site is acquired. As measurement conditions, one OCT data acquisition time is 0.2 seconds, the image size is 1 mm × 1 mm, the frame interval is 1 second, and OCT images of sweat glands are continuously acquired for about 5 minutes (300 seconds). Stimulation sound is heard as stress of mental sweating, and sweating related to skin sympathetic nerves is promoted and observed by dynamic OCT. For example, when the subject is told of an unpleasant sound (volume 90 dB, duration 0.5 seconds) when the glass is broken, the sweating of the fingertip is promoted in response to this sound. When the sympathetic nerve is normal, sweating is promoted when a sound stimulus is applied, and the signal intensity of the sweat glands greatly increases on the OCT image. A grip force load may be applied instead of the sound stimulus.
指の先端部では、エクリン汗腺が４００〜６００個／ｃｍ２の密度で分布し、指紋の山に沿って並んでいる。撮像素子３１を使用することにより、この汗腺の中から対象とする能動汗腺を特定し、同一汗腺についてダイナミックＯＣＴ測定を行うことが可能である。 At the tip of the finger, the eccrine sweat glands are distributed at a density of 400 to 600 pieces / cm 2 and are lined up along the crest of the fingerprint. By using the imaging device 31, it is possible to identify the target active sweat gland from the sweat glands and perform dynamic OCT measurement on the same sweat gland.
次に、測定手順について説明する。最初に、指先をサンプルホルダ４７に固定し、指紋部にある汗腺の表面像を撮像素子３１で撮影し、画像モニター３２に表示する。表示エリアは５×５ｍｍ２で、指紋の頂点部が中心になるように固定する。ＯＣＴ走査範囲を画像モニター３２に表示した後、信号処理部５０の操作によりｘｙステージ４３およびθステージ４６を移動して、所望の汗腺を断層画像の走査ラインの中心部に位置決めする。そして、被験者に外部負荷をかけて汗腺からの発汗を促すとともに、特定した能動汗腺のダイナミックＯＣＴ測定を行い、発汗量を測定する。 Next, the measurement procedure will be described. First, the fingertip is fixed to the sample holder 47, and the surface image of the sweat glands in the fingerprint portion is captured by the image sensor 31 and displayed on the image monitor 32. The display area is 5 × 5 mm 2 and is fixed so that the apex of the fingerprint is at the center. After the OCT scanning range is displayed on the image monitor 32, the xy stage 43 and the θ stage 46 are moved by the operation of the signal processing unit 50, and the desired sweat gland is positioned at the center of the scanning line of the tomographic image. Then, an external load is applied to the subject to encourage sweating from the sweat gland, and dynamic OCT measurement of the identified active sweat gland is performed to measure the amount of sweat.
次に、汗腺の内部発汗と外部発汗について説明する。本発明者は、皮膚表面の汗孔が開かない精神性発汗現象を発見し、これを「内部発汗」と名付けた。内部発汗は、真皮（皮膚の深部）から螺旋状の汗腺ダクトに吸い上げられる汗の量が少なく、皮膚表面に汗滴（汗の粒）が放出されない発汗である。これに対して、皮膚表面に裂け目（汗孔）が生じ、汗滴が皮膚表面に放出されるものを「外部発汗」という。この外部発汗は通常見られる発汗現象であり、既存の「発汗計」で皮膚表面の湿度変化を測定することによって検出できる。 Next, internal sweating and external sweating of sweat glands will be described. The present inventor discovered a mental sweating phenomenon in which the sweat pores on the skin surface do not open, and named this “internal sweating”. Internal sweating is sweating in which the amount of sweat sucked from the dermis (deep part of the skin) to the spiral sweat gland duct is small and sweat drops (sweat particles) are not released on the skin surface. On the other hand, a case where a tear (sweat hole) occurs on the skin surface and sweat drops are released on the skin surface is called “external sweating”. This external sweating is a commonly observed sweating phenomenon and can be detected by measuring the humidity change on the skin surface with an existing “sweat meter”.
本実施形態に係るＯＣＴ装置の特徴は、上記の外部発汗と内部発汗を識別して、両者の発汗量を定量測定できることにある。特に、発汗量が少なく、既存の発汗計では検出不可能な内部発汗を高感度に検出することが可能になる。なお、汗腺の汗孔が閉じた状態で汗腺内部に存在する発汗量を測定する手法と、汗孔が開いた状態で汗腺内部に存在する発汗量を測定する手法とは同じである。 The feature of the OCT apparatus according to the present embodiment is that the above-mentioned external sweating and internal sweating can be identified and the amount of sweating of both can be quantitatively measured. In particular, the amount of sweating is small, and internal sweating that cannot be detected by existing sweatmeters can be detected with high sensitivity. The method for measuring the amount of sweat existing inside the sweat gland with the sweat pores of the sweat gland closed and the method for measuring the amount of sweat existing inside the sweat gland with the sweat pores opened are the same.
図３は、発汗量の測定手法の一例を示す説明図である。例えば、被験者が右手で棒を強く握ると、脳の神経中枢および交感神経を通じて、左手指先の発汗が促進される。これを握力負荷という。図３（ｄ）のグラフは、測定対象の指とは反対の手で棒を１０秒間強く握ったときの瞬時発汗量を示す。この瞬時発汗量は、次の画像処理によって測定することができる。
（ａ）一定のフレーム間隔で汗腺ダクトのＯＣＴ画像を時系列に取得する。
（ｂ）ＯＣＴ画像において皮膚表面を示す輝線を削除する。
（ｃ）螺旋状汗腺の背景ノイズとなる画素の中で、反射光強度が最大値となる画素を抽出し、この値を閾値として設定し、閾値以下の値を持つ画素の反射光強度をゼロにする（これを「閾値処理」という）。さらに、表皮と真皮の境界にある明るい部分（コラーゲン層）を回避するように、関心領域（ＲＯＩ：Region of interest）を設定する。
（ｄ）ＲＯＩに含まれる螺旋状汗腺を構成する全ての画素の反射光強度を積算する。この積算値が「汗腺に蓄えられる瞬時発汗量」に対応する。
FIG. 3 is an explanatory diagram illustrating an example of a method for measuring the amount of sweating. For example, when the subject holds the stick with his right hand, sweating of the left fingertip is promoted through the nerve center of the brain and the sympathetic nerve. This is called grip force load. The graph of FIG. 3 (d) shows the amount of instantaneous sweating when the hand is gripped for 10 seconds with the hand opposite to the finger to be measured. This instantaneous sweating amount can be measured by the following image processing.
(A) OCT images of sweat gland ducts are acquired in time series at regular frame intervals.
(B) The bright line indicating the skin surface is deleted from the OCT image.
(C) Among the pixels that are the background noise of the spiral sweat glands, the pixel having the maximum reflected light intensity is extracted, this value is set as a threshold value, and the reflected light intensity of the pixel having a value equal to or smaller than the threshold value is zero. (This is referred to as “threshold processing”). Furthermore, a region of interest (ROI) is set so as to avoid a bright part (collagen layer) at the boundary between the epidermis and dermis.
(D) The reflected light intensity of all the pixels constituting the spiral sweat gland included in the ROI is integrated. This integrated value corresponds to “instantaneous perspiration accumulated in sweat glands”.
図４は、特定のエクリン汗腺についての発汗状態の時間変化を示す説明図である。ここでは、計測開始から５０秒経過した時点で１０秒間握力負荷をかけて、５０秒後からフレーム間隔１秒で時系列にＯＣＴ画像を取得している。６２秒後に、皮膚表面に汗孔が開き始めた様子が読み取れる。汗孔が開いてからの発汗量は従来の発汗計でも測定可能であったが、汗孔が閉じた状態でも汗腺内部に水分が存在していることがＯＣＴ計測により初めて明らかになった。握力負荷がかかってからは、安静状態の画像とは異なり、信号強度が強くなり、精神性発汗が促進されていることが判る。汗孔が閉じた状態における内部発汗量を測定することにより、外部発汗に至らない発汗量を測定できるので、精神性発汗発汗現象を高感度に測定することができる。 FIG. 4 is an explanatory diagram showing the time change of the sweating state for a specific eccrine sweat gland. Here, a grip force load is applied for 10 seconds when 50 seconds have elapsed from the start of measurement, and OCT images are acquired in time series at a frame interval of 1 second after 50 seconds. After 62 seconds, it can be seen that sweat holes have begun to open on the skin surface. Although the amount of sweating after the opening of sweat holes could be measured with a conventional sweat meter, OCT measurement revealed for the first time that moisture was present inside the sweat glands even when the sweat holes were closed. It can be seen that, unlike the image in the resting state, the signal intensity is increased and the mental sweating is promoted after the grip strength load is applied. By measuring the amount of internal sweating in a state where the sweat pores are closed, the amount of sweating that does not lead to external sweating can be measured, so that the mental sweating and sweating phenomenon can be measured with high sensitivity.
図５は、内部発汗の様子を示すもので、図５（ａ）はＯＣＴ画像の時間変化を示し、図５（ｂ）は内部発汗量の時間変化を示すグラフであり、図５（ｃ）は従来の発汗計で計測した発汗量の時間変化を示すグラフである。 FIG. 5 shows the state of internal sweating, FIG. 5 (a) shows the time change of the OCT image, FIG. 5 (b) is a graph showing the time change of the internal sweat amount, and FIG. 5 (c). FIG. 6 is a graph showing the change over time in the amount of sweat measured by a conventional sweat meter.
図５（ｂ）において、縦軸は汗腺ダクト内部の信号強度を積分した値（内部発汗量）を瞬時発汗量（リニア表示、任意単位）として示している。横軸は経過時間（秒）を示す。測定開始から５０秒で被験者に音刺激を与えると、発汗が促され、信号強度が大きく増大し、約６０〜７０秒でピークに達し、その後、発汗が減少し、約２００秒経過すると、安静状態と同様な状態に戻ることが判る。 In FIG. 5 (b), the vertical axis represents the value obtained by integrating the signal intensity inside the sweat gland duct (internal sweat amount) as the instantaneous sweat amount (linear display, arbitrary unit). The horizontal axis indicates elapsed time (seconds). When a sound stimulus is given to the subject in 50 seconds from the start of measurement, sweating is promoted, the signal intensity increases greatly, reaches a peak in about 60 to 70 seconds, and then decreases in sweating. It turns out that it returns to the state similar to a state.
図５（ａ）の１枚目の画像は測定開始から３８秒（刺激前）のもので、汗腺ダクト内には水分が殆ど存在していない。２枚目の画像は測定開始から６５秒のもので、汗腺ダクト内に水分が充満しているが、汗孔は閉じたままである（内部発汗）。３枚目の画像は測定開始から１１０秒のもので、汗腺ダクト内に排出された水分が組織に徐々に吸収されている。 The first image in FIG. 5A is 38 seconds (before stimulation) from the start of measurement, and there is almost no moisture in the sweat gland duct. The second image is 65 seconds from the start of the measurement, and the sweat gland duct is filled with water, but the sweat holes remain closed (internal sweating). The third image is 110 seconds from the start of measurement, and the water discharged into the sweat gland duct is gradually absorbed by the tissue.
一方、図５（ｃ）において、縦軸は発汗計で測定した発汗量、横軸は経過時間（秒）であり、音刺激の前後に渡って数値が殆ど変化していない。このことは、従来の発汗計では内部発汗の測定が原理的に不可能であることを示している。 On the other hand, in FIG. 5C, the vertical axis represents the amount of sweat measured with a sweat meter, and the horizontal axis represents the elapsed time (seconds), and the numerical values hardly change before and after the sound stimulation. This indicates that internal sweating cannot be measured in principle with a conventional sweat meter.
図６は、外部発汗の様子を示すもので、図６（ａ）はＯＣＴ画像の時間変化を示し、図６（ｂ）は総発汗量の時間変化を示すグラフであり、図６（ｃ）は汗孔の直径の時間変化を示すグラフであり、図６（ｄ）は従来の発汗計で計測した発汗量の時間変化を示すグラフである。外部発汗では、音刺激の代わりに握力負荷を用いている。 FIG. 6 shows the state of external sweating, FIG. 6 (a) shows the time change of the OCT image, FIG. 6 (b) is a graph showing the time change of the total sweat amount, and FIG. 6 (c). Is a graph showing the change over time in the diameter of the sweat pores, and FIG. 6D is a graph showing the change over time in the amount of sweat measured by a conventional sweat meter. In external sweating, grip force load is used instead of sound stimulation.
図６（ｂ）において、縦軸は汗腺ダクト内部および外部の信号強度を積分した値（総発汗量）を瞬時発汗量（リニア表示、任意単位）として示している。横軸は経過時間（秒）を示す。測定開始から５０秒で被験者に握力負荷を与えると、発汗が促され、信号強度が大きく増大し、約６０〜７０秒でピークに達し、その後、いったん発汗が減少し、約９０秒で再び増加して、約１１０〜１２０秒でピークに達し、その後、発汗が減少し、約２５０秒経過すると、安静状態と同様な状態に戻ることが判る。 In FIG. 6B, the vertical axis indicates the value (total sweat amount) obtained by integrating the signal intensity inside and outside the sweat gland duct as the instantaneous sweat amount (linear display, arbitrary unit). The horizontal axis indicates elapsed time (seconds). When grip force is applied to the subject in 50 seconds from the start of measurement, sweating is promoted, the signal intensity increases greatly, reaches a peak in about 60 to 70 seconds, and then decreases once and increases again in about 90 seconds. Then, the peak is reached in about 110 to 120 seconds, and after that, the perspiration decreases, and after about 250 seconds, it returns to the state similar to the resting state.
図６（ａ）の１枚目の画像は測定開始から４７秒（刺激前）のもので、汗腺ダクト内には水分が殆ど存在していない。２枚目の画像は測定開始から５３秒のもので、汗腺ダクト内に水分が充満し始めており、汗孔も開きつつある（外部発汗）。３枚目の画像は測定開始から６２秒のもので、汗腺ダクト内に充満する水分量が増大するとともに、汗孔が大きく開いている。４枚目の画像は測定開始から９４秒のもので、汗腺ダクト内での水分量はあまり減少していない。 The first image in FIG. 6A is 47 seconds (before stimulation) from the start of measurement, and there is almost no moisture in the sweat gland duct. The second image is 53 seconds from the start of measurement, and the sweat gland duct is beginning to fill with moisture, and sweat holes are opening (external sweating). The third image is 62 seconds from the start of measurement, and the amount of water filling the sweat gland duct increases and the sweat holes are greatly opened. The fourth image is 94 seconds from the start of measurement, and the amount of water in the sweat gland duct has not decreased much.
図６（ｃ）において、縦軸は汗孔の直径（μｍ）で、横軸は経過時間（秒）である。汗孔の直径は、縦に延びる皮膚表面の画像に対して閾値処理を施すことによって容易に計測できる。汗孔は、測定開始から約６３秒〜約１００秒の期間だけ開いて、その前後では閉じていることが判る。 In FIG.6 (c), a vertical axis | shaft is the diameter (micrometer) of a sweat hole, and a horizontal axis is elapsed time (second). The diameter of the sweat pores can be easily measured by performing threshold processing on an image of the skin surface extending vertically. It can be seen that the sweat holes are opened only for a period of about 63 seconds to about 100 seconds from the start of measurement, and are closed before and after that.
一方、図６（ｄ）では、握力負荷の時点から発汗量が増加し始めて、約６０〜７０秒でピークに達し、その後、発汗が減少し、約１２０秒経過すると、安静状態と同様な状態に戻ることが判る。図６（ｄ）のグラフは、図６（ｂ）と比べると、ノイズが少なく、２回目のピークも現れていない。これは、従来の発汗計ではカプセルの開口面積に包含される多数の汗腺を合算して測定していることに起因している。これに対してＯＣＴ計測では、特定の汗腺に関する反応を観測できるため、個々の汗腺ごとに詳細な情報を取得できるという利点がある。 On the other hand, in FIG. 6D, the amount of perspiration begins to increase from the time of grip force load, reaches a peak in about 60 to 70 seconds, and after that, when the perspiration decreases and about 120 seconds elapse, the state is similar to the resting state. It turns out to return to. The graph of FIG. 6D has less noise than the graph of FIG. 6B, and the second peak does not appear. This is due to the fact that in the conventional sweat meter, a large number of sweat glands included in the opening area of the capsule are combined and measured. On the other hand, OCT measurement has an advantage that detailed information can be acquired for each sweat gland because a reaction related to a specific sweat gland can be observed.
なお、以上の説明では、ＯＣＴ計測としてタイムドメイン(ＴＤ：Time domain)方式ＯＣＴ計測を用いた場合を例示したが、その他のＯＣＴ計測、例えば、フーリエドメイン(ＦＤ：Fourie domain)方式ＯＣＴや超高速光コムＯＣＴなどでも本発明は適用可能である。 In the above description, the case where time domain (TD) method OCT measurement is used as the OCT measurement is exemplified. However, other OCT measurement, for example, Fourier domain (FD) method OCT or ultra-high speed is used. The present invention can also be applied to an optical comb OCT or the like.
また、被験者の測定部位として指の掌面を例示したが、その他の部位、例えば、手掌や手背、足底などでも本発明は適用可能である。 Further, although the palm surface of the finger is exemplified as the measurement site of the subject, the present invention can be applied to other sites such as the palm, the back of the hand, and the sole of the foot.
本発明は、被験者の皮膚に分布するエクリン汗腺の発汗量を高感度で測定できる点で、産業上極めて有用である。 INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially in that the amount of sweat of the eccrine sweat glands distributed on the subject's skin can be measured with high sensitivity.
１０ ＯＣＴ計測部
１１ ＳＬＤ光源
１２ 光ファイバカプラ
１３，１６ 光位相変調器
１４ 照射部
１７ 参照光ミラー
１８ 光検出器
２１ フィルタ
２３ Ａ／Ｄ変換器
２５ ファンクションジェネレータ
３１ 撮像素子
３２ 画像モニター
３３ フレームグラバー
４１ Ｄ／Ａ変換器
４２ ステージドライバー
４３ ｘｙステージ
４４ ｚステージ
４６ θステージ
５０ 信号処理部
５１ ガルバノミラー
Ｌ１，Ｌ２，Ｌ３，Ｌ４ 光路
DESCRIPTION OF SYMBOLS 10 OCT measurement part 11 SLD light source 12 Optical fiber coupler 13, 16 Optical phase modulator 14 Irradiation part 17 Reference light mirror 18 Photo detector 21 Filter 23 A / D converter 25 Function generator 31 Image sensor 32 Image monitor 33 Frame grabber 41 D / A converter 42 Stage driver 43 xy stage 44 z stage 46 θ stage 50 Signal processor 51 Galvanometer mirror L1, L2, L3, L4 Optical path
Claims (5)
ＯＣＴ画像を解析することにより、エクリン汗腺の汗孔が閉じた状態で特定のエクリン汗腺内部に存在する水分の信号強度の積算値に基づいて特定のエクリン発汗量を測定するステップを含むことを特徴とする発汗量測定方法。 A method of measuring the amount of sweat in a specific eccrine sweat gland distributed in the palm of the subject,
Analyzing the OCT image, and measuring a specific amount of eccrine perspiration based on an integrated value of the signal intensity of water present in the specific eccrine sweat gland with the sweat pores of the eccrine sweat gland closed. A method for measuring the amount of sweating.
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