Heating of Biological Tissues by Gold Nano Particles: Effects of Particle Size and Distribution

摘要

This paper deals with hyper thermal therapy of tumors in biological tissues using dispersions of gold nano spheres. These spheres are heated with a laser beam in the near infrared range based on surface plasmon resonance phenome-non. The single sphere problem gives a surface temperature rise following a universal form with a characteristic time τ proportional to the sphere surface and inverse diffusivity of the surrounding medium. The temperature front is found to reach a finite range when traveling into the surrounding medium with a certain time delay. The many particles problem is treated as a convolution product of the sphere density distribution function and the particle temperature profile. Different space distribution functions of nano particles are considered. A uniform sphere distribution provides a good coverage of medium heating while a Gaussian distribution predicts an important drop of temperature when approaching the borders of the treated region. Lorentzian distribution was also considered for comparison. An effort is made to highlight the impacts of the obtained results in developing strategies for hyper thermal therapy in a joint effort with the medical team.