Figure 3 Schematic of the damage of radiation on bone. Radiation therapy (RT) can cause the development of osteoporosis and fragility fractures, mainly involving osteoclasts, osteoblasts and immune cells. The differentiation and number of osteoblasts are increased, making the bone resorption happen. While in osteoblasts, cell cycle arrest occurs, and the matrix deposition and proliferation rate are reduced. Meanwhile, the immune response is enhanced, and pro-inflammatory cytokines are secreted by immune cells. TNF-α – tumor necrosis factor-α; IL-1 – interleukin-1; IL-6 – interleukin-6. Created with BioRender.com.