【摘 要】
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We proposed a nonlinear photoacoustic[PA]technique as a new imaging contrast mechanism for tissue thermal-nonlinearity characterization.When a sine-modulated Gaussian temperature field is introduced by a laser beam,in view of the temperature dependence of
【机 构】
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MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science,College of Biophotonics,S
论文部分内容阅读
We proposed a nonlinear photoacoustic[PA]technique as a new imaging contrast mechanism for tissue thermal-nonlinearity characterization.When a sine-modulated Gaussian temperature field is introduced by a laser beam,in view of the temperature dependence of the thermal diffusivity,the nonlinear PA effect occurs,which leads to the production of second-harmonic PA[SHPA]signals.By extracting the fundamental frequency PA and SHPA signal amplitudes of samples through the lock-in technique,a parameter that only reflects nonlinear thermal-diffusivity characteristics of the sample then can be obtained.The feasibility of the technique for thermal-nonlinearity characterization has been studied on phan-tom samples.In vitro biological tissues have been studied by this method to demonstrate its medical imaging capability,prefiguring great potential of this new method in medical imaging applications.
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