Brain metastasis is very common, about 30% incidence rate for all patients with a diagnosis of cancer. The rising incidence of brain metastasis is most likely due to recent advances in systemic therapy, and use of magnetic resonance imaging (MRI). The most common primary site is the lung followed by breast. One of the standard treatments is whole brain radiotherapy; it can prolong the decline of neurocognitive function and improve quality of life. However, it can also cause decline in neurocognitive function as a late sequela. Memory impairment is the main cognitive function that affected by radiotherapy, and the neuronal stem cells located at hippocampal subgranular zone are highly sensitive to radiotherapy. There have been large randomized trials confirming that by HA-WBRT, the neurocognitive function decline can be reclaimed. In Taiwan, HA-WBRT is a popular and emerging treatment. However, not much study focused on its effects on neurocognitive function. The study is aimed to objectively investigate the memory preservation and neurocognitive function protection of HA-WBRT in people speaking Mandarin Chinese or Taiwanese by utilizing neurocognitive function test and QoL questionnaire.