The 21-aminosteroid U74389G exhibits radioprotection effect on normal brain tissue, but does not appear to protect the tumor in an in vivo rat radiosurgery model. Kondziolka et al. believed that the observed beneficial effects on healthy brain led to significant prolongation of animal survival; perhaps, by limiting the adverse effects of high-dose radiosurgery. This radioprotectant should be evaluated in randomized clinical trials in patients with malignant brain tumors ¹⁾