著者

清野 公宏 鈴木 郁斗 野川 雅道 五十嵐 朗 内藤 尚 小川 充洋 山越 憲一 高田 重男 田中 志信

出版者

公益社団法人 日本生体医工学会

雑誌

生体医工学 (ISSN:1347443X)

巻号頁・発行日

vol.55Annual, no.5PM-Abstract, pp.460, 2017 (Released:2017-09-13)

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これまで我々は腎・尿路系疾患発見に重要な指標である尿成分を全自動で計測可能なトイレ内蔵型尿成分計測システムの開発を最終目的として,近赤外光を用いた尿糖計測法について基礎的検討を続けてきた.具体的には糖尿病の早期発見に有用なグルコースをメインターゲットとし,蛋白摂取量の指標である尿素,塩分摂取量の指標である塩化ナトリウム,尿中成分の排出量測定に有用なクレアチニンの4成分について,糖尿病が疑われる成人男性等から採取した尿(高尿糖随時尿)などを対象に各4成分の濃度推定を行ってきた.その結果計測波長範囲(750-2500nm)の中から各成分の感度波長を4種類選定し重回帰モデルを構築することで,実用に供し得る精度で濃度予測が可能であることを確認した.今回は実用化に向けて,多波長LEDを光源とした場合の測定精度を次のような方法で検証した.すなわちFT-IRで得た透過光強度スペクトルに対して,中心波長の重みを1,半値幅を200nmとしたガウス関数を乗じることで,LEDのブロード状の発光特性を模擬し,上述の重回帰分析を行った. その結果,グルコース,クレアチニンについてはγ=0.7前後で濃度予測精度の更なる向上を要するものの,尿素,塩化ナトリウムについてはγ>0.8以上となり,多波長LEDを光源として用いることの妥当性が確認できた.

著者

田中 志信 本井 幸介 野川 雅道 山越 健弘 山越 憲一

出版者

公益社団法人 日本生体医工学会

雑誌

生体医工学 (ISSN:1347443X)

巻号頁・発行日

vol.44, no.3, pp.467-474, 2006 (Released:2008-05-01)

参考文献数

18

被引用文献数

1

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The daily monitoring of health conditions at home is a very important subject not only as an effective scheme for the early diagnosis and treatment of cardiovascular and other diseases, but also for the prevention and control of such diseases. From this point of view, we have been developing a fully automated “non-conscious” monitoring system for home healthcare. In this paper, we describe the structural details of a newly developed blood pressure (BP) measurement system built into a toilet seat and some results obtained using the system. The principle used for BP measurement was the volume-oscillometric method. A reflectance-type photoplethysmographic sensor was installed in an appropriate position on the toilet seat, and it was automatically lifted and lowered using a newly designed helicoid-type actuator. Systolic (SBP) and mean BP (MBP) were obtained using the arterial volume pulsation signal obtained by the sensor. In order to evaluate the accuracy of the BP measurements, simultaneous measurements were carried out using two types of commercially available BP monitors (upper arm and wrist). Simultaneous measurement using an “invasive technique” via catheterization to the right brachial artery was also conducted. From the results obtained (bias[s.d.] for SBP; Upper arm: -1.20 [7.90] mmHg, Wrist: 0.44 [7.28] mmHg, Invasive: -0.41 [4.91] mmHg, bias [s.d.] for MBP; Upper arm: 4.40 [6.91] mmHg, Wrist: 5.07 [8.04] mmHg, Invasive: 3.68 [5.69] mmHg), reasonable accuracy of the present system was clearly demonstrated. This system, which requires no cumbersome procedures for BP measurement such as cuff setting, proper positioning of measuring site and so on, appears to be a useful means for long-term home healthcare monitoring.

著者

田中 志信 小川 充洋 野川 雅道

出版者

金沢大学

雑誌

基盤研究(B)

巻号頁・発行日

2014-04-01

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今年度は、昨年度10波長まで絞り込んだ使用波長について、慢性腎症の進行予防に有用な指標である「尿素・クレアチニン比(U/Cr)」を得るための至適波長組み合わせについて検討した。その結果、各成分の濃度を4または5種類の波長で高精度(実測濃度と推定濃度との相関係数:γ>0.99)で推定可能な波長組み合わせを見出すことが出来た。このうち2波長は各成分で同一だったため実質「7波長」でU/Crを得ることができ、その精度もγ=0.904と極めて良好であることが確認された。一方実用化への移行(光源のLED化)を考慮して近赤外マルチチップLEDを新たに試作し,グルコース,尿素の単一水溶液を用いて濃度推定の可否を検討した. LED試作に当たってはグルコース及び尿素の感度波長であり、かつ近赤外領域において水の吸収が最も大きな2,200nmをピーク波長とするマルチチップ(4個×6列)LEDを試作した.そして各成分の濃度推定に必要なLEDの光強度(換言すればチップ数)を明らかにすることで,他の波長の必要チップ数に関する知見を得ることを目的とた.溶質としてはグルコース及び尿素を選び、それぞれの単一水溶液(10, 50, 100mg/dl)を調製し,各溶液の差分吸光度から重回帰分析により各成分におけるγを求めた。その結果、尿素では1列(4チップ)発光でγ=0.995という高精度が得られたのに対して、グルコースでは3列(12チップ)発光でようやくγ=0.669という結果となった。これらの結果は、2200nmが尿素の感度波長であるのに対して、グルコースにおいては感度波長ではあるもののモル分子吸光係数自体が尿素に比べ極めて小さいために濃度予測が難しかったと考えられ、多波長のマルチチップLEDの設計(波長選定)にこの結果を生かしていく予定である。

著者

熊橋 智史 野川 雅道 内藤 尚 田中 志信

出版者

公益社団法人 日本生体医工学会

雑誌

生体医工学 (ISSN:1347443X)

巻号頁・発行日

vol.54, no.26, pp.S109, 2016

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<p>Toward a development of noninvasive tissue oxygen consumption monitoring method, we propose an arteriovenous blood oxygen saturation measurement based on near-infrared spectroscopy. For arterial blood oxygen saturation measurement, we employ a conventional arterial blood oxygen saturation measurement method, pulse oximetry. Then, for venous blood oxygen saturation measurement, based on a similar principle of pulse oximetry, we developed a new venous blood photoplethysmographic oximetry using cyclic cuff compression technique (mean pressure: 10mmHg with 10mmHg amplitude, cyclic frequency: 0.1Hz). The noninvasive arteriovenous blood oxygen saturation measurement system comprises two-wavelength, 750/830nm. The calibration curve of blood oxygen saturation measurement was calibrated, without blood-drawing, using theoretical photon propagation model based on radiative transfer. The newly designed noninvasive arteriovenous blood oxygen saturation measurement system was evaluated with healthy subjects' forearms during isometric hand-grip exercise. The noninvasive measurement system could offer reasonable blood oxygen saturation changes during the exercise and following resting period.</p>

著者

田中 茂雄 野川 雅道 山越 憲一

出版者

公益社団法人 日本生体医工学会

雑誌

生体医工学 (ISSN:1347443X)

巻号頁・発行日

vol.44, no.4, pp.582-587, 2006 (Released:2008-05-29)

参考文献数

8

被引用文献数

3

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The purpose of this study is to investigate the optical absorbance spectrum of bone tissue in the near-infrared region for the development of bone densitometry using near-infrared light. Using bone samples from a bovine femur, optical absorbance spectrums were measured between 750∼2500 nm. With high bone density, the absorbance increased beyond 1400 nm. To predict bone density from the spectrum data, pairs of wavelengths with absorbance ratios or differences having a high correlation coefficient (r>0.99) with bone density were identified. One of the best results was shown by a pair of 1200 nm and 1550 nm with coefficients(r) of 0.994 and 0.996 for absorbance ratio and difference, respectively. Even in thedensity range of the trabecular bone, the coefficients were 0.892 and 0.881 for absorbance ratio and difference, respectively. The results suggest the possibility applying near-infrared spectroscopy to bone densitometry.

著者

田中 志信 本井 幸介 野川 雅道 山越 健弘 山越 憲一

出版者

日本生体医工学会

雑誌

生体医工学 : 日本エム・イー学会誌 = Transactions of the Japanese Society for Medical and Biological Engineering : BME (ISSN:1347443X)

巻号頁・発行日

vol.44, no.3, pp.467-474, 2006-09-10

被引用文献数

3

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The daily monitoring of health conditions at home is a very important subject not only as an effective scheme for the early diagnosis and treatment of cardiovascular and other diseases, but also for the prevention and control of such diseases. From this point of view, we have been developing a fully automated "non-conscious" monitoring system for home healthcare. In this paper, we describe the structural details of a newly developed blood pressure (BP) measurement system built into a toilet seat and some results obtained using the system. The principle used for BP measurement was the volume-oscillometric method. A reflectance-type photop-lethysmographic sensor was installed in an appropriate position on the toilet seat, and it was automatically lifted and lowered using a newly designed helicoid-type actuator. Systolic (SBP) and mean BP (MBP) were obtained using the arterial volume pulsation signal obtained by the sensor. In order to evaluate the accuracy of the BP measurements, simultaneous measurements were carried out using two types of commercially available BP monitors (upper arm and wrist). Simultaneous measurement using an "invasive technique" via catheterization to the right brachial artery was also conducted. From the results obtained (bias [s.d.] for SBP; Upper arm: -1.20 [7.90] mmHg, Wrist: 0.44 [7.28] mmHg, Invasive: -0.41 [4.91] mmHg, bias [s.d.] for MBP; Upper arm: 4.40 [6.91] mmHg, Wrist: 5.07 [8.04] mmHg, Invasive: 3.68 [5.69] mmHg), reasonable accuracy of the present system was clearly demonstrated. This system, which requires no cumbersome procedures for BP measurement such as cuff setting, proper positioning of measuring site and so on, appears to be a useful means for long-term home healthcare monitoring.