數位X光影像(Computed Radiography, CR)的應用是未來醫學影像的主流，除了可以減少重照率更重要的是可以減低劑量。與傳統X光影像不同的是：傳統X光影像有特性曲線的效應，可供判讀的範圓大部分受限於輻射劑量，螢光屏(screen)和軟片(film)之間的作用則為較固定的影響變數。由於影像板(IP, image plate)的材料與影像成像軟體使用的參數，影響影像品質的程度較大，本研究的目的為評估不同的數位X光影像系統，分別利用影像後處理的技術配合適當的X光劑量，以得到良好的數位X光影像。我們利用兩種數位X光影像系統(FUJI CR, AGFA CR)於一般X光機組進行單一假體實驗，當影像獲取後，以影像處理系統的參數設定去判讀分析CR參數所對應的管電壓(kVp)與管電流(mAs)之容許範圈。實驗發現當管電壓增加時，不論ACR或FCR，灰階越高影像越黑，並且隨著管電壓的增加，輻射劑量越低。因此本研究最終希望能藉此提供在可採用容許範圍內，可獲得較佳的影像品質，並較少的輻射劑量。

Computed Radiology (CR) systems are currently most common type of digital imaging used in radiology departments for reducing the retake rate and radiation dose. This wonderful technology replaces conventional screen-film system. Unlike conventional screen-film where the range of exposures is subjected to characteristic curve, CR has a wide dynamic of exposures range. Since the material of image plate and image processing software would affect image quality, the aim of this study was to evaluate radiation dose by using image post-processing parameter with two CR systems (FUJI CR, AGFA CR). In order to analyze the exposure latitude corresponding to kVp and mAs, we evaluated image quality and dose for an image quality phantom underwent imaging processing systems. When increased kVp, the more pixel value, the more dark image. Moreover, the radiation dose would reduce while higher kVp had been used. Our suggestion for this study was that in a clinical setting, the use of optimized CR exposure factor would result in a lower exposure dose and higher image quality.