目的：本篇主要測量 Varian CL-2100C/D sn:48 I 動態式楔形濾板在不同照野的穿透因子，以做為建立臨床動態式楔形濾板劑量學資料之一環，並與固定式楔形濾板因子做比較，以了解動態式楔形濾板劑量上不同於固定式楔形濾板的特性，增加對動態式楔形濾板劑量學上的了解及使用上應考量的因素。材料與方法： 以 N.E. 0.6 cc Farmer Type 游離腔置於 Scanditronix RFA-300 水假體射束中心軸深度 5 cm （ 6 MV ）及 10 cm （ 15 MV ）處，將水假體表面置於 100 cm 處，游離腔長軸與濾板橫切面呈垂直， 分別測量 15 °、30 °、45 °、60 °固定式及動態式楔形濾板各正方形照野之穿透因子，以觀察並比較其變化。結果：固定式楔形濾板之穿透因子隨照野變大有增大之趨勢，平均約增加 3%； 動態式楔形濾板穿透因子一般較固定式楔形濾板之穿透因子大，與照野大小之變化關係則呈不規則之變小趨勢，相差最大達 35%。結論：動態式楔形濾板在國內應用之經驗尚淺，對其劑量學上之特性應予多方了解，比如等劑量分佈曲線，穿透因子與照野之關係等，由本文之結果得知動態式楔形濾板穿透因子與照野之關係不呈規則性變化，對臨床應用上，由於變化極大，劑量計算時應視其照野大小正確查得其因子，以求得正確之監測單位；另外，欲對一般電腦治療計畫系統建立動態式楔形濾板資料庫時，亦應對穿透因子的不規則變化仔細考慮其劑量學的準確性。

　　　　　Purpose:The transmission factors of each dynamic and fixed wedge weremeasured for Varian CL-2100 C/D sn:481 linear accelerator. The factors were usedto set-up the clinical treatment data tables for clinical dosimetry for dynamicwedges utilization. The data will be used to set-up the computer treatmentplanning database also.Materials and Methods: The N.E. 0.6 cc Farmer type chamber (Type:2571)connectedto Ionex Dosemaster 2590 was installed on the chamber frame of ScanditronixRFA-300 water phantom with water prove protector. The axis of the chamber isperpendicular to the transverse plane of the wedge. Output factors in water weremeasured on the central axis of each field at 5-cm depth for 6 MV and 10-cmdepth for 15 MV X-rays. The phantom was positioned with the water surface at 100cm SSD. Measurements were performed for field sizes ranging from 4.0-20.0 cm andfor equivalent square field to 25 cm. the measurements were performed for open,for fixed and dynamic wedge angles. The transmission factor of each field sizewas calculated from the output with/without wedge.Results:The transmission factors of each fixed wedges were increased as fieldsize increase. The increment is around 3%. The factors of the dynamic wedge werelarger than the fix ones, but the factors were decreased irregularly when fieldsize increase. The maximum decrement is 35%.Conclusion:Tranmission factor is an important parameter in clinical applicationsof wedge filters. The variation of the factors of dynamic wedges verse fieldsize is not the same as fixed ones and more complex. Due to the variation of thefactors, one should take more attention in the application and the data input ofthe planning system.