Radiation therapy, alongside chemotherapy and surgery, is one of the most effective treatments for cancer. Ionizing radiation used in radiotherapy is delivered to the tumour using an external beam (teleradiotherapy) or an internally placed radiation source (brachytherapy). Radiation therapy aims to provide a high therapeutic dose to the tumour volume without exceeding the tolerance of normal tissues, which is often a limitation of the maximum radiation dose, which can be toxic to normal tissues surrounding the tumour. To increase the radiotherapeutic efficacy, while reducing the side effects of radiation therapy, nanotechnology has proved to be promising, offering many unique features that can be used in oncology.

Nanotechnology is an interdisciplinary field of research. It includes engineering, chemistry, biology, medicine, and mathematics, and has great potential for early detection, accurate diagnosis, and treatment of cancer. One such area of interest is nanomedicine, which deals with problems related to nanoscale diseases. One of the methods of nanomedicine used to potentially improve the contrast between normal and cancer cells is the use of heavy contrast agents. It is claimed that the dose of delivered ionizing radiation can be amplified by the presence of high-Z materials via an enhancement of the photoelectric effect. Thus, heavy elements can be potent radiosensitizers and the radiation dose enhancement depends upon the composition and size of the particles, the uptake of particles into cells, and the energy of the applied radiation. Gold nanoparticles have proved to be the most prospective for this application as gold exhibits, on a nanometre scale, size and shape specific physical, chemical, electronic, and magnetic properties, which are different from the bulk and its isolated atoms. The physicochemical properties (size, shape, coating and functionalization, etc.) of nanoagents influence their pharmacokinetics, bioavailability, biodistribution, as well as targeting and intracellular delivery. This allows us to tune the properties of gold nanoparticles for biomedical applications. In addition, gold nanoparticles combine high X-ray absorption, high density, and biocompatibility, which makes them an ideal contrast agent for radiotherapy. The mathematical models of nanoparticles in tissues are helpful in the studies of radio-sensitisation and will allow us to improve the understanding of the intracellular physical and biological processes with nanostructures, as well as the influence of nanoparticles’ shape, size and concentration in cells on the therapy efficiency.

This Special Issue aims to collate original research articles focussed on new aspects of the modelling of nanoparticles in oncology for radiation therapy. In addition, review articles discussing the current state of the art are also welcomed.

Potential topics include but are not limited to the following:

• Computational modelling of nanoparticles for application in teleradiotherapy
• Mathematical models of biological systems with nanoparticles in radiotherapy
• Modelling nanomaterial physical properties in radiation therapy
• Computational modelling of nanoparticle-cellular membrane interactions with or without radiation
• Modelling of nanoparticles applied to cancer immunoregulation
• Study of models of nanoparticles for diagnostics
• Modelling of superparamagnetic nanoparticles for use in medicine
• Use of scientific codes as GEANT4 or MCNPX for nanodosimetry in radiotherapy
• Modelling of nanoparticles applied to enhancement of a dose to cancer
• New techniques and approaches of Monte Carlo simulation of nanoobjects in radiation therapy