Side-scattered finger-photoplethysmography: Experimental investigations toward practical noninvasive measurement of blood glucose

Yasuhiro Yamakoshi*, Kenta Matsumura, Takehiro Yamakoshi, Jihyoung Lee, Peter Rolfe, Yuji Kato, Koichi Shimizu, Ken Ichi Yamakoshi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


The aim of this study was to discover a simple/convenient geometrical arrangement of radiation sources and detector to acquire finger-photoplethysmograms (PPGs) with wavelength regions of blood glucose (BGL) absorption, toward practical noninvasive BGL measurement. First, we compared PPGs with three wavelengths: 808 nm (without water absorption), 1160 nm (with weak water absorption), and 1600 nm (with nearly peak BGL absorption and strong water absorption), while the source-detector spacing was successively increased circumferentially around a fingertip. In 10 healthy subjects, we observed clear cardiac-related pulsatile components of PPG signals at 808 and 1160 nm in any incident positions with more than 15 dB of signal-to-noise ratio (S/N), but reliable PPG detections at 1600 nm with more than 10 dB of S/N was only possible when the source-detector distance was less than 3 mm around the fingertip circumference. Second, with this arrangement, an experiment was performed using six wavelengths to cover glucose absorption bands (from 1550 to 1749 nm), obtaining pulsatile PPG signals with more or less 15 dB of S/N. Through the present experiments, this orthogonal arrangement of the source and detector to detect forward- and side-scattered radiation through the tissue is appropriate for PPG measurements with wavelength regions where there is potential for BGL measurement.

Original languageEnglish
Article number067001
JournalJournal of Biomedical Optics
Issue number6
Publication statusPublished - 2017 Jun 1


  • blood glucose absorption pulse glucometry
  • finger-photoplethysmography
  • laser diode
  • side-scattered radiation
  • water absorption

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering


Dive into the research topics of 'Side-scattered finger-photoplethysmography: Experimental investigations toward practical noninvasive measurement of blood glucose'. Together they form a unique fingerprint.

Cite this