Gold Nanoparticles for Imaging and Radiotherapy

The physical mechanisms of action involved when heavy atoms are embedded in biological systems subject to ionising radiation are described with a particular view to providing models for the use of (gold) nanoparticles as targeted agents intended to improve both diagnostic imaging and radiotherapy. Fundamental interactions between ionising radiation and matter are reviewed and then invoked to describe the specific processes arising when nanoparticles containing heavy atoms, and particularly gold nanoparticles, are irradiated in biological systems. Shortcomings in simple macroscopic models of dose distribution are discussed, with the concept of nanodosimetry being used to account for the large effects observed. Finally, some open questions and future research directions are reviewed.