The present application relates to activable inorganic nanoparticles which can be used in the health sector, in particular in human health, to disturb, alter or destroy target cancerous cells, tissues or organs. It more particularly relates to nanoparticles which can generate a surprisingly efficient therapeutic effect, when concentrated inside the tumor and exposed to ionizing radiations. The invention also relates to pharmaceutical compositions comprising a population of nanoparticles as defined previously, as well as to their uses.