體內金屬植入物會導致電腦斷層影像產生金屬假影，影像中的假影主要是射束硬化和光子不足所引起的，而產生的條紋和陰影假影會使相鄰解剖結構的影像受到嚴重的損壞，進而影響影像判讀與臨床診斷。本篇為一病例報告，比較兩種常見的金屬假影減少技術，一為疊代金屬假影減少(iterative metal artifact reduction, iMAR)技術，另一種為雙能量電腦斷層(dual-energy computed tomography, DECT) 的虛擬單能影像(virtual monoenergetic image)，觀察使用兩種技術對於單側髖關節金屬植入物和腰椎金屬植入物的影像差異。經觀察發現兩種技術皆能進一步減少金屬假影，但運用在不同的身體部位上效果仍然各有不同。

Metal implants in the body will cause metal artifacts in the computed tomography image. The artifacts in the image are mainly caused by beam hardening and photon starvation, and the resulting streak and shadow artifacts will seriously affect the image of adjacent anatomical structures. The damage will further affect the image interpretation and clinical diagnosis. This study is a case report which compares two common metal artifact reduction techniques, one is iterative metal artifact reduction (iMAR) technology, and the other is virtual monoenergetic image of dual-energy computer tomography (DECT). To observe the difference in imaging of unilateral hip metal implant and lumbar metal implant using two techniques. It has been observed that both techniques can further reduce metal artifacts, but the effects on different metal implants are still different.