頭部電腦斷層掃描劑量評估

近年來電腦斷層檢查所產生的輻射劑量，已成為非常受到重視的議題。由於電腦斷層檢查已成為急診與門診重要的檢查工具之一，病患於疾病的診療過程中，往往會接收到相當可觀的輻射劑量。然而對於不同的部位、不同疾病、不同放射科醫師甚至不同時候的檢查，病患接受的掃描方式皆可能不盡相同，因此，每一次的掃描都可能給病患不同程度的輻射劑量。本研究的主要目的，是在可接受的影像品質之前提下，對臨床病患所接受到電腦斷層掃描檢查的輻射曝露，進行合理的降低；以每週測量電腦斷層劑量指標（CT dose index, CTDI）為基準，將紀錄下來的病患的掃描參數轉換為劑量長度乘積（dose-length product, DLP），作為該病患該次檢查的輻射劑量指標。並經由資料分析，建立該項檢查之診斷參考水平（diagnostic reference level, DRL），並據與放射專科醫師研討協商後此設定改進目標，達到降低病患輻射劑量之目的。研究結果顯示：成人組和兒童組在降低管電壓峰值（kVp）14.3%及管電流時間乘積（mAs）23.8%時，在對假體影像品質沒有顯著受影響之前提下，修正對臨床病患接受電腦斷層掃描檢查時的掃描參數，可以達成維持影像品質與降低輻射劑量至原本的68.4%及76.1%。

關鍵字

電腦斷層劑量指標；劑量長度乘積；輻射劑量；影像品質

並列摘要

The radiation dose of CT scans has become an important issue in recent years. Since the CT scan is become an important tool in routine and emergency exams, patients may receive lots of radition exposure in diagnosis and treatment of diseases. In addition, the patients may experience different CT scans according to different body parts, diseases, responsible radiologists, and situations. Therefore, the patients receive different radiation exposures in every CT scans. The primary objective in this study is the to reasonably reduce the radiation dose of CT scans in acceptable image quality. The CTDI (computed tomography dose index) of each performed CT scan protocols is evaluated weekly, and the collected patient data and displayed dose information is recorded accordingly. Finally, the DRL (diagnostic reference level) of each protocol is established and a discussion with radiologists is held in protocol dose reduction. The results show that without significant changes in the image quality, the reduction of 14.3% kVp or 23.8% mAs will reduce the radiation dose to 68.4% and 76.1% respectively.

並列關鍵字

Computed Tomography Dose Index ； Diagnostic Reference Level ； Radiation dose ； Image Quality

國際替代計量

頭部電腦斷層掃描劑量評估

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