Deep penetration of light into biotissue

Edward D. Bearden; James D. Wilson; Vladimir P. Zharov; Curtis L. Lowery M.D.

doi:10.1117/12.434729

9 July 2001 Deep penetration of light into biotissue

Edward D. Bearden, James D. Wilson, Vladimir P. Zharov, Curtis L. Lowery M.D.

Proceedings Volume 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical; (2001) https://doi.org/10.1117/12.434729
Event: BiOS 2001 The International Symposium on Biomedical Optics, 2001, San Jose, CA, United States

Abstract

The results of a study of deep (several centimeters) light penetration into biological tissue are presented in order to estimate its significance to potentially photosensitive structures and processes including the fetal eyes. In order to accomplish this goal, samples of various tissues (fat, muscle, and uterus) from surgical patients and autopsies were examined with a double integrating sphere arrangement to determine their optical properties. The results were implemented in a Monte Carlo modeling program. Next, optical fiber probes were inserted into the uterus and abdominal wall of patients undergoing laparoscopic procedures. The fibers were couples to a photomultiplier tube with intervening filters allowing measurements of light penetration at various wavelengths. To determine the feasibility of stimulation in utero, a xenon lamp and waveguide were used to transilluminate the abdomen of several labor patients. Light in the range of 630 to 670 nm where the eye sensitivity and penetration depth are well matched, will likely provide the best chance of visual stimulation. Fetal heart rate, fetal movement, and fetal magnetoencephalography (SQUID) and electroencephalography (EEG) were observed in different studies to determine if stimulation has occurred. Since internal organs and the fetus are completely dark adapted, the amount of light required to simulate in our opinion could be on the order of 10(superscript -8 Watts.

Citation Download Citation

Edward D. Bearden, James D. Wilson, Vladimir P. Zharov, and Curtis L. Lowery M.D. "Deep penetration of light into biotissue", Proc. SPIE 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical, (9 July 2001); https://doi.org/10.1117/12.434729

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