Many studies revealed the high potential of multifunctional nanoparticles for biomedical applications. Since these nanoparticles can be designed for combining imaging and remotely controlled therapeutic activity, image-guided therapy which rests on the induction of nanoparticles toxicity by external stimulus when the nanoparticles content is both high in the diseased zone and low in the healthy tissue can be envisaged, especially for fighting cancer (one of the most important cause of mortality in several countries). Image-guided therapy should lead to valuable improvements in radiation-based therapy provided that the multifunctional radiosensitizing nanoparticles developed for increasing the selectivity of the radiotherapy (and therefore the efficiency) meet the criteria imposed by in vivo applications and by the physical principles of the interaction between radiation and the matter.
