Since several decades ago, it has been understood that hippocampus plays an essential role in memory function. Not little evidence supports that radiation-induced damage to hippocampus should be strongly associated with NCF impairment. Furthermore, several studies have shown that isodose distribution in hippocampus is closely related to neurocognitive function in patients with benign or low-grade brain tumors. As a consequence, it is hypothesized that conformal hippocampal sparing during the course of WBRT (HS-WBRT) might provide significant preservation in terms of cognitive function.