To prevent radiation-induced loss of neuronal stem cells, hippocampus-sparing (HS) radiation techniques have been developed and efficacy has been demonstrated in the recently published phase II RTOG 0933 study. The trial included patients with brain metastases and a Karnofsky Performance Scale (KPS) of 70%. Following HS-WBRT the patients showed a relative neurocognitive function (NCF) decline of 7% four months after HS-WBRT, which is more than four times less than observed in studies with conventional WBRT (30%; p<0.001).