Influence of immersion agents on optical parameters of bio-tissues during laser photothermal therapy of tumor: pilot study

Abstract

Combined use of an immersion agent with low-intensity laser irradiation for optical clearing of skin before plasmon photothermal therapy (PPTT) procedure is offered. Pilot study results of influence of the immersion agents on optical parameters of skin, subdermal connective tissue and model tumor of rats in vivo at hyperthermia during PPTT are presented. Model of alveolar liver cancer --- cholangiocarcinoma, transplanted under the skin, was used as a model tumor. For PPTT the gold nanorods with absorption band in the area of diode laser radiation (808 nm) were introduced. Monitoring of light attenuation coefficient change in skin at optical clearing was performed using optical coherent tomography. Measurements of optical parameters of the complete tumor and its layers were performed using spectrometers in a wave length range of 350-2200 nm. Reduction of skin thermal damage during PPTT with preliminary optical clearing using immersion agent (mixture of 70% glycerol water solution and 10% DMSO) and low-intensity laser irradiation at wave length of 808 nm is observed. Keywords: gold nanorods, IR laser radiation, optical clearing, optical parameters, plasmon photothermal therapy.