醫用直線加速器（linear accelerator，LINAC）為現今放射腫瘤科最主要治療癌症之技術，對於深部的病灶常予以高能量光子射束照射，然而，當光子能量超過6.2 MeV時，光子會與治療機頭（treatment head）內高原子序數之物質作用產生光中子（photoneutron），由於中子屬於強穿輻射（strongly penetrating radiation），存在於機頭內的光中子會直接穿透屏蔽光子之物質滲漏至加速器的環境中，藉由多次碰撞（multiple collisions）及散射，分佈於治療室（treatment room）與迷道（maze）中，造成其環境周遭不必要之中子劑量（undesirable neutron dose）；本研究採用多球體偵檢器搭配計算中子能譜之程式用以計算照野外（out-off field）之中子通量，並轉換成中子劑量予以評估，同時也探討影響中子能譜變化之因子。建立此實驗技術，未來可提供輻射防護與臨床之參考，亦為保健物理領域中盡一份心力。

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