We enrolled the patients who were assigned to therapeutic WBRT for the treatment of BM, skull metastasis, dural metastasis, leptomeningeal dissemination of cancer, or central nervous system (CNS) involvement of non-Hodgkin lymphoma (NHL) from April 2012 to May 2014 at Niigata University Hospital and Niigata Cancer Center Hospital. We also included patients with limited-disease small cell lung cancer (LD-SCLC) who were assigned to prophylactic WBRT. Patients with a neurological deficit, such as a consciousness disorder, hemiparesis, visual defect, or aphasia, that could disturb the neuropsychological examinations were excluded. The dose fractionation of therapeutic WBRT was 35 Gy in 14 fractions over 3 weeks at Niigata University Hospital, and 30 Gy in 10 fractions over 2 weeks at Niigata Cancer Center Hospital. The fractionation of prophylactic WBRT was 25 Gy in 10 fractions over 2 weeks at both institutions. After WBRT, a follow-up neuroradiological examination was performed with contrast-enhanced x-ray computed tomography (CT) or magnetic resonance imaging (MRI) every 2–6 months. Written consent was obtained from all patients or their relative before WBRT. This study was approved by the Institutional Review Board of Niigata University Hospital (Study #1449).