There is no acknowledged and effective standard treatment for radiation-induced brain injury (RI). Glucocorticoids and bevacizumab during acute period are optional ways to reduce the brain edema. However, glucocorticoids and bevacizumab are unsuitable or ineffective for some patients, especially in the early stage of RI. The investigators supposed that angiogenesis might play a key role in the pathogenesis of RI, and that thalidomide, as an antiangiogenic drug, would reduce immature angiogenesis and improve vessel maturation in RI.