Fig. 1

Biological effects of ionizing radiation on human normal tissues. In radiotherapy, ionizing radiation causes a variety of biological effects that result in cellular damage. Ionizing radiation causes cellular DNA breakage, leading to apoptosis and senescence. In addition, ionizing radiation causes oxidative damage due to an imbalance of oxidative stress. During cancer treatment, ionizing radiation can cause damage to the heart, liver, lung, kidney, intestines, skin and other organs. The stages of damage are mainly divided into acute and chronic fibrosis. (Figure was created with https://www.Biorender.com)