Relationship between wavelength combination and signal-to-noise ratio in measuring hemoglobin concentrations using visible or near-infrared light

• Published in: Optical review (Tokyo, Japan) Japan), 2009-07, Vol.16 (4), p.442-448
• Main Authors: Funane, Tsukasa, Atsumori, Hirokazu, Sato, Hiroki, Kiguchi, Masashi, Maki, Atsushi
• Format: Article
• Language: English
• Subjects: Atomic; Biological and medical sciences; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects, investigation technics, apparatus; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lasers; Microwaves; Molecular; Optical and Plasma Physics; Optical Devices; Optical instruments, equipment and techniques; Optics; Photonics; Physics; Physics and Astronomy; Quantum Optics; Regular Papers; RF and Optical Engineering; Tissues, organs and organisms biophysics
• ISSN: 1340-6000; 1349-9432
• DOI: 10.1007/s10043-009-0084-6

The signal-to-noise ratio (SNR), when using visible or near-infrared light to measure the change in hemoglobin concentration length (the product of hemoglobin concentration and optical path length in this study), depends on the wavelength combination and the analysis method. Although the SNRs increase when detected or incident optical power increases, the optical power should be limited because of safety standards. Considering these safety standards, we assumed that the total optical power was constant by using the relationship between optical power and measurement error. We investigated the theoretical estimation errors of the changes in hemoglobin concentration length using two, three, and four different wavelengths. The SNRs of the changes in hemoglobin concentration length were high when fewer wavelengths were used. These SNRs decreased when the redox state change in cytochrome oxidase was included in the analysis.