頭部電腦斷層為臨床最常使用檢查之一，有鑑於小兒對輻射敏感度高於一般成人，輻射工作人員應盡可能降 低電腦斷層掃描劑量以期達到合理抑低(As Low As Reasonably Achievable , ALARA)原則，避免造成輻射劑量與相關致癌風險效應機率増加，現今臨床對於小兒電腦斷層都使用一般成人之掃描條件或者依據成人掃描條件修改後進行掃描，造成患者接受之輻射劑量往往過高。
本研究依據年齡分成五個實驗群組：A組是新生兒組0歲到6個月、B組是6.1個月至18個月、C組是18.1個月至3歳、D組是3歲到10歲及E組是10歲到15歲，實驗組分別使用不同的掃描設定與對照組比較其掃描長度及體積電腦斷層劑量指標值(volume computed tomography dose index, CTDIv)、劑量長度乘積值(dose-length product, DLP)與有效劑量，進一歩評估結果是否符合美國放射醫學會與歐盟之劑量水平建議值，並期望提供臨床參考小兒頭部電腦斷層掃描參數設定之建議。

Computed tomography of the brain exam that most commonly used clinical examination, while the children for radiation be sensitive than the adult so should minimize CT dose to achieving low as reasonably achievable (ALARA) principle, to avoid radiation dose caused increased probability of tumor and biological effects.
Absorbed radiation dose in children is often too high, that current clinical used the adult’s or adult’s base scan protocol to modify for pediatric CT exam.
This study divided into five experimental groups for age: A group for newborns group 0 to 6 months, B group was 6.1 months to 18 months, C group was 18.1 months to 3 year age, D group was 3 year age to 10 year age, E group is 10 to 15 years age. The experimental groups was used different Scan protocol with control groups of it’s Volume computed tomography dose index, CTDIv, does-length product, DLP and effective dose. Further assessment whether the result conform to American College of Radiology and European Union’s suggested value of dose level, and expect to provide clinical reference pediatric head CT scan protocol.