Summary of numerical analyses for therapeutic uses of laser-activated gold nanoparticles

The optimal light dose, heat generation, consequent heat spread and an accurate thermal damage model, are key components of effective laser therapies. Recent advances in nanotechnology offer numerous possibilities on how to increase the efficacy of hyperthermia for tumour treatments. Gold nanoparticles are a promising candidate towards the achievement of this goal owing to their properties for efficiently converting light to heat. In this review, we summarise the numerical tools that are available for theoretical studies of gold-nanoparticle-mediated photo-thermal therapy. The processes that occur in the treatments based on light propagation inside biological tissues and the subsequent temperature distributions are considered first, followed by evaluation of the thermal damage. The fundamental ideas underlying the presented methods are described in addition to their applications in photo-thermal therapy and its effects. The descriptions of extensively used tools for the characterisation of nanoparticles across multiple research fields are also presented for estimating the electromagnetic properties of gold nanoparticles (e.g. discrete dipole approximations, finite-difference time-domain simulations), the Monte Carlo model of light propagation in biological tissues, and the Pennes' bio-heat equation. In addition, the Arrhenius damage evaluation and the cumulative effective minutes normalisation methods are described. Finally, recent in vivo and in vitro results from the rapidly growing field of nanomedicine are presented.