電腦斷層用於胸部結節檢查，已發展為低劑量電腦斷層(low dose computed tomography, LDCT)掃描技術，主 要目的為降低輻射劑量，同時電腦斷層影像又可以清晰的篩檢出早期肺癌之非鈣化小結節。隨著科技的進步，更 新的多切面電腦斷層技術問世，成為早期肺癌篩檢最佳利器。本研究採用回溯方式，共分析了100 位受檢者。兩 組受檢者BMI 相似，並使用相同的設定參數，以64 切與128 切雙射源多切面電腦斷層掃描儀(dual source computer tomography, DSCT)進行檢查，並比較其差異性。結果指出兩台DSCT 對於低劑量胸部檢查出小結節最小直徑分別 為1.4 mm 和1.6 mm，幾乎沒差別。但在輻射劑量方面，顯示128 切DSCT 在平均容積電腦斷層劑量指數、平均 劑量長度乘積及平均有效劑量皆比64 切DSCT 較少(P<0.0001)。使用新式電腦斷層掃描儀即可在維持可判讀影像 品質之下，更降低輻射劑量。

Lung nodule detection by computerized tomography has developed into a low-dose scan because of new CT device. The purpose of this study is to reduce the radiation dose and at the same time, the computer tomography images can be clearly to detect early lung cancer of the non-calcified nodules. With the advancement of science and technology, newer multi-slice computer tomography (MSCT) technology has become the best weapon for early lung cancer screening. This study adopted a retrospective approach and total of 100 subjects were analyzed. The two groups of subjects were with similar BMI, the same setting of parameters, but using 64-slice and 128-slice dual source multi-slice CT (DSCT) examination, retrospectively. Comparing these two groups, the results show that the two DSCT for low-dose chest examination of small nodules can reveal minimum diameter of 1.4mm and 1.6mm. But in the radiation dose, the 128-slice DSCT had fewer CT dose index (CTDIvol), mean dose-length products, and mean effective dose (E) than 64-slice DSCT (P<0.0001). Using the newer CT scanner can not only maintain interpretable image quality but also reduce the radiation dose.