Amyloid-β (Aβ) plaques and neurofibrillary tangles are the pathological hallmarks for AD. Accumulation of Aβ is considered to be the first step of pathophysilogy of AD. Compelling researches have supported TBI accelerates the formation and accumulation of Aβ. These findings could link TBI with AD but the previous researches had limitations. There was lack of mTBI pathology data so the impacts of mTBI on Aβ accumulation were still obscure. By amyloid-PET, we could study the effects of mTBI on the accumulation of Aβ and this tool could be helpful for understanding the real impacts and pathophysiological mechanisms of mTBI on AD.