Red laser attenuation in biological tissues: study of the inflammatory process and pigmentation influence

Caetano P. Sabino; Daiane T. Meneguzzo; Endi Benetti; Ilka T. Kato; Renato A. Prates; Martha S. Ribeiro

doi:10.1117/12.907400

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9 March 2012 Red laser attenuation in biological tissues: study of the inflammatory process and pigmentation influence

Caetano P. Sabino, Daiane T. Meneguzzo, Endi Benetti, Ilka T. Kato, Renato A. Prates, Martha S. Ribeiro

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Proceedings Volume 8211, Mechanisms for Low-Light Therapy VII; 821105 (2012) https://doi.org/10.1117/12.907400
Event: SPIE BiOS, 2012, San Francisco, California, United States

Abstract

Several studies indicate that low level laser therapy (LLLT) accelerates the healing process, however, for a determined pathology, dosimetry remains difficult to be established. To understand the tissue optical properties under different conditions is extremely relevant since the dose delivered to the target tissue is known to be critical. The skin pigmentation influence on the laser attenuation is not yet well established on different mice lineages or human ethnical groups, making the dose problematic. Along the same line, inflammatory processes may cause similar problems since the tissues in this condition change their optical properties due to inflammatory cell accumulation. This work evaluated the attenuation pattern of a HeNe laser (λ=632.8 nm) using ex vivo skin samples from Balb/C and C57BL/6 mice under inflammatory stages induced in their paw by local carrageenan inoculation. The samples were placed between two microscope slides, and a CCD camera was placed orthogonal to the beam path. The intensity distribution of the scattered light was photographed in grayscale and analyzed by ImageJ software. Our findings suggest that even slight differences of the epithelial pigmentation could result in a relevant dose loss delivered to the deeper tissues. The increase of the inflammatory cell density in the connective tissue indicated a highly scattering area also resulting in a dose loss for the deeper tissues when compared to control group.

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Caetano P. Sabino, Daiane T. Meneguzzo, Endi Benetti, Ilka T. Kato, Renato A. Prates, and Martha S. Ribeiro "Red laser attenuation in biological tissues: study of the inflammatory process and pigmentation influence", Proc. SPIE 8211, Mechanisms for Low-Light Therapy VII, 821105 (9 March 2012); https://doi.org/10.1117/12.907400

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