Investigation of optical absorption induced temperature change and amplification of photoacoustic signal of contrast dye

摘要

Temperature dependence of photoacoustic (PA) signal is a crucial factor in PA temperature sensing, imaging, and monitoring of thermal therapies. In this study, we report theoretical and simulation studies to describe the temperature dependence of PA-signal and hence the Grueneisen parameter. A light-absorbing organic dye (Methylenc blue) is taken as the sample, and the variation of PA-signal against change in temperature is plotted from the simulated data. Experiments were conducted employing a home-built photoacoustic microscopy imaging system to measure PA signal for the validation study. A CW-laser beam (of wavelength, 642nm) is used to vary the temperature of the organic dye during the experiment, and the average PA-signal is measured from the acquired PA image. The change in temperature of the sample due to the laser irradiation is noted separately. PA-signal strength and its amplification against temperature change is plotted from the experimental data. It is observed that the experimental results are well-matched with the theory and simulated data.