Multi-wavelength measurement of cytochrome oxidase and water in biomedical tissues using optical topography system

Tsukasa Funane, Hirokazu Atsumori, Hiroki Sato, Masashi Kiguchi, Atsushi Maki

Research output: Contribution to journalConference articlepeer-review


Optical topography is a brain function imaging technology based on near-infrared spectroscopy, whereby changes in oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) are observed. There are several components other than hemoglobin in biomedical tissue such as cytochrome oxidase (cyt-ox) and water, and it is important to measure them. We investigated the possibilities of multi-wavelength measurement of the changes in oxy-and deoxy-Hb, the redox state of cyt-ox, and water based on a modified Beer-Lambert law. According to error propagation theory, we searched for the wavelength combination where the estimation errors were minimal in the wavelength range from 650 to 900 nm under several conditions of measured components and number of wavelengths. Next, using the experimental data, we performed the same search. The signal-to-noise ratio (SNR) loss depended on measured components and wavelengths used in the measurement. We calculated the necessary improvement in precision of absorbance measurement when we estimated the changes in the redox state of cyt-ox and water, for maintaining the same level of SNRs in the hemoglobin-only measurement. The measurements of both the redox state of cyt-ox and water were not practical because the SNR losses of Hb became more than 30 dB, while the measurement where only one of them was performed was more feasible. We calculated the required ratio of absorbance change to its noise for the acquisition of cyt-ox at the same SNR of oxy-hemoglobin in hemoglobin-only measurements when the absorbance change caused by cyt-ox was assumed to be one tenth of that of oxy-hemoglobin.

Original languageEnglish
Article number71740A
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Publication statusPublished - 2009 May 5
Externally publishedYes
EventOptical Tomography and Spectroscopy of Tissue VIII - San Jose, CA, United States
Duration: 2009 Jan 252009 Jan 27


  • Cytochrome oxidase
  • Hemoglobin
  • Multi-wavelength measurement
  • Optical topography
  • Signal-to-noise ratio
  • Water

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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