Fig. 1

Schematic of nanoparticle functional mechanisms in radiotherapy. Combing ionizing radiation (IR) with nanoparticles (NPs) can boost radiosensitization, cell apoptosis and cytotoxicity. Upper: Metallic NPs (Au, Hf, Gd and Bi) deposit the IR dose through interactions, such as electron secretion (Compton, Auger and photoelectric), ROS generation and energy amplification. Down: Non-metallic NPs-encapsulated combined with radiotherapy further induced DNA damage and prevented rapid DNA repair, which will cause more cell apoptosis