比較胸部電腦斷層容積劑量指數與體型特異性劑量評估之差異

Comparison of the Dose Difference between the Chest Computed Tomography Volume Dose Index and the Body-specific Dose Assessment

陳鏗鏘(Keng-Chiang Chen) ； 王基誠(Ji-Cheng Wang) ； 鄭旭萌(Syu-Meng Jheng) ； 雷粟蓉(Li-Jung Lei)

《中華放射線技術學雜誌》 45卷1期 (2021/03) Pp. 48-53

摘要

本研究為比較體型特異性劑量評估（Size-specific Dose Estimates, SSDE）與容積電腦斷層劑量指數（CTDI_(vol)），在評估成人胸部電腦斷層檢查所接受的輻射劑量之間差異。本研究通過人體試驗委員會的批准，回溯性分析2019年1月至5月之間，300位執行成人胸部電腦斷層檢查之患者。研究內容將患者按照國人身體質量指數（BMI）（kg/m^2），分成過輕體位、健康體位及過重體位三個組別（A組為BMl＜18.5 kg/m^2；B組為18.5≦BMI＜24 kg/m^2）；C組為24kg/m^2≦BMI）。本研究選擇未注射顯影劑之電腦斷層影像作為比較。掃描參數設定管電壓固定為120 kVp及參考管電流為110 mAs。我們依據美國醫學物理學家協會第204號報告（AAPM 204）中的轉換因子來評估SSDE。並比較CTDI_(vol)值之間的差異。研究結果顯示，A、B、C三組CTDI_(vol)平均劑量分別為4.78 ± 0.98 mGy、6.0 ± 1.28 mGy和7.6 ± 1.9 mGy。A、B、C三組SSDE平均劑量分別為7.1±1.29 mGy、8.1±1.2 mGy和9.28±1.6 mGy。兩種劑量評估方式皆有顯著差異（p＜0.0001）。使用CTDI_(vol)評估患者所接受之輻射劑量時會比較低。在BMl＜18.5kg/m^2群組兩種劑量評估方式差異越大。

關鍵字

電腦斷層 ； 體型特異性劑量評估 ； 電腦斷層劑量指標

並列摘要

The study was to compare the difference between the size-specific dose estimates(SSDE)and the computed tomography dose index(CTDI_(vol))to assess the radiation dose received by adult chest computed tomography. This study was approved by the institutional review board and retrospectively analyzed 300 patients who underwent adult chest computerized tomography between January and May, 2019. According to the Taiwan body mass index (BMI)(kg/m^2), the patients were divided into three groups: underweight range, healthy range and overweight range(group A is BMl＜18.5 kg/m^2, group B is 18.5≦BMI＜24 kg /m^2, group C is 24 kg/m^2≦BMI). This study compares computer tomography images without injection of contrast media. CT imaging using the standard protocol with a fixed tube voltage of 120 kVp and the reference tube current is at 110 mAs. We used the conversion factor in the American association of physicists in medicine report No. 204 (AAPM 204) to evaluate SSDE. And compare the difference between CTDI_(vol). The results of the study showed that the average doses of CTDI_(vol) in groups A, B, and C were 4.78 ± 0.98 mGy, 6.0 ± 1.28 mGy, and 7.6 ± 1.9 mGy, respectively. The average doses of SSDE in groups A, B, and C were 7.1 ± 1.29 mGy, 8.1 ± 1.2 mGy, and 9.28 ± 1.6 mGy, respectively. There was a significant difference between CTDI_(vol) and SSDE(p ＜ 0.0001). Using CTDI_(vol) method to evaluate, the received radiation dose will be relatively low. In the group of BMl ＜ 18.5 kg/m^2, the difference in the way of dose assessment is greatest.

並列關鍵字

Computed Tomography (CT) ； Size-specific Dose Estimates (SSDE) ； Computed Tomography dose index (CTDI_(vol))