多葉準直儀是取代傳統放射治療、順形治療和強度調控放射治療鉛合金遮擋塊的一個方便且有效節省成本之替代工具，且已變成新購加速器的標準配備。在此多葉準直儀元件用於臨床治療前，其幾何及劑量特性必須正確的測量並與傳統鉛合金遮擋鉛塊照野的特性相比較。本論文的主題探討了：波浪型邊緣劑量分佈平順法、正方形照野的全面性劑量特性關係之測量與研究，包括：準直儀、假體、全部散射因子，尖峰散射因子，中心軸深度劑量—百分深度劑量或組織最大比因子，探討並測量不同離軸位置相向葉片啣合處輻射洩漏量對危及器官的傷害。最後測量並定量出各葉片啟動時的加速及停止前的減速速度及定速度，以建立葉片速度在執行強度調控放射治療時，因葉片運動速度對劑量分佈造成影響的快速檢測方法。

Multi-leaf collimator (MLC) is a convenient and cost-effective tool as a substitute for alloy blocks for conventional radiation therapy, conformal therapy and intensity modulation radiation therapy (IMRT). It is becoming a standard feature on new accelerator. Before the unit used clinically, the geometric and dosimetry characteristics must be measured and verified to compare with the conventional blocking fields. The object of this dissertation is to investigate the staggered dose distribution smoothing methods, the comprehensive dosimetry characteristics include the collimator, phantom, total scatter factors, peak-scatter factor (PSF), central axis depth dose (PDD or TMR) were evaluated at least for square shaped fields. The abutted region dose leakage at different off-axis distance (OAD) was examined to evaluate the radiation hazard of critical organ at this region. We also develop a technique to examine the stability of leaf speed include the effect of acceleration and deceleration of leaf motion in order to make sure the stability of leaf speed will not affect the intensity profile generated.

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