低劑量電腦斷層掃描應用於腹部掃描之評估

The Evaluation of Abdominal Scan by Using Low Dose Computed Tomography

洪煥明(Juan-Ming Hung) ； 林孟萱(Meng-Hsuan Lin) ； 史天宇(Tian-Yu Shih) ； 鄭凱元(Kai-Yuan Cheng)

《中華放射線技術學雜誌》 46卷1期 (2022/03) Pp. 42-47

摘要

電腦斷層檢查可以協助醫師瞭解各種身體之疾病，病人亦可避免許多高危險性的侵入性檢查。隨著低劑量電腦斷層使用率的提高，如何避免輻射對人體的危害，在保有一定水準的影像品質下，降低病人輻射劑量的議題越受重視。本次研究利用擬人假體評估不同設定條件於腹部電腦斷層掃描之曝露劑量與影像訊雜比，以期獲得較低的輻射曝露並能得到最佳的影像品質參數。針對電腦斷層掃描參數之管電壓與管電流分別進行調整，圈選影像中固定之區域比較影像訊雜比，並評估肝臟、脾臟、腎臟、胃、小腸、膀胱與睪丸之曝露劑量。結果顯示調降管電壓與管電流為80 kVp, 100 mAs，則平均訊雜比下降為0.283，且影像呈現非常粗糙；若管電壓固定為120 kVp調降管電流為100 mAs則平均訊雜比為0.753；評估器官曝露劑量顯示睪丸在各個條件都獲得最高的曝露劑量，最高可達到25.27 mGy。本次研究顯示當腹部電腦斷層掃瞄參數設定為120 kVp, 100mAs時，可獲得比訊雜比平均值較佳的影像，且有效等效劑量最多可以下降51.53%。

關鍵字

低劑量電腦斷層掃描 ； 管電壓 ； 管電流 ； 曝露劑量

並列摘要

Computed tomography can help doctors diagnosis various diseases, thus patients can avoid many high-risk invasive examinations. With the increased using of low dose computed tomography, the issue of reducing the radiation dose of patients while maintaining the image quality has become more and more important. In this study, an anthropomorphic phantom was used to evaluate the exposure dose and the signal-to-noise ratio of abdominal computed tomography images with different settings, in order to obtain lower radiation exposure and the best image quality parameters. Adjust the tube voltage and tube current of the CT scan parameters separately. Circle the fixed area in the images to compare the signal-to-noise ratio between them, and evaluate the exposure dose of liver, spleen, kidney, stomach, small intestine, bladder and testicles. The results showed when the tube voltage and tube current were 80 kVp, 100 mAs, the average signal-to-noise ratio dropped to 0.283, and the image became rough. If the tube voltage was fixed at 120 kVp, the tube current was 100 mAs, then the average signal-to-noise ratio was 0.753. The evaluation of the organ dose showed that the testicles obtained the highest dose under all conditions, and the highest one could reach 25.27 mGy. This study showed the image was better than the one with average signal-to-noise ratio when the parameters of abdominal computed tomography were 120 kVp, 100 mAs and the effective dose can be reduced by up to 51.53%.

並列關鍵字

low dose computed tomography ； tube voltage ； tube voltage ； exposure doses