Monte Carlo Simulation of Enhanced Laser Absorption in Tumors With Gold Nanorod Injection

The employment of gold nanoshells or nanorods in photothermal emerges as a promising technology in treatment of cancers in the past several years [1–4]. Gold nanoshells consist of a solid dielectric core nanoparticle (∼100 nm) coated by a thin gold shell (∼10 nm). Gold nanorods are usually small with a size of ∼10 nm and an aspect ratio of approximately four. By varying the size ratio, the nanostructures can be tuned to have strong absorption and scattering to a specific near infrared (NIR) laser at ∼800 nm. The enhancement in laser energy absorption is several orders of magnitude compared to some traditional dyes [1]. The laser energy absorbed in an area congregating by the nanostructures is transferred to the surrounding tissue by heat conduction. The nanostructures in tumors not only enables targeted delivery of laser energy, but also maximally concentrates a majority of the laser energy to the tumor region.