Quantitative Measurement of ROS Penetration into Model Tissue Under Plasma Treatment Using Image Processing

Plasma dose quantification is one of the core problems in clinical of plasma medicine. The spatial-temporal distribution and the total dose of the reactive species from plasma into the processed object are especially important in clinic. In this study, we developed a measurement scheme based on image processing technology for quantifying the penetration dose of reactive oxygen species (ROS) into model tissues, and analyzed the effects of treatment conditions on the concentration distribution and the total amount. First, by establishing a numerical relationship between the color index and ROS concentration through image processing and titration experiment, the spatial concentration distribution of ROS on each sliced layer of the treated sample was calculated. Then, the ROS penetration depth was obtained through image segmentation of longitudinal sliced tissue image. Finally, by integrating the concentration of each layer and the depth, the absolute amount of ROS was obtained. Both the penetration depth and absolute amount exhibit a positive correlation with treatment time and a negative correlation with treatment distance under an Ar plasma jet treatment. A range of penetration depth of 0.5–3 mm and total dose of 0.05–0.47 µmol was obtained under the setting conditions. The effectiveness of the proposed method was confirmed by comparing with the total ROS amount measured by UV-Vis method dissolved in liquid, providing a new solution for the issue in plasma dose quantification, and is also benefit for the understanding of plasma-tissue interaction.