Objective: To evaluate the difference of the 3D image quality between the low-dose and the standard-dose chest CT.
Methods: Eleven patients were randomly scanned with the standard-dose CT and 9 with the low-dose CT. Quality of the images from both groups was evaluated by different postprocessing techniques.
Results: The effective tube current, total tube current, and CT dose index volume were (114.55 +/- 26.20) mAs, (1578.27 +/- 353.09) mAs, and (7.76 +/- 1.77) mGy, respectively, in the standard-dose scanning group, and were 20 mAs, (566.11 +/- 46.23) mAs, and (1.46 +/- 0.07) mGy, respectively, in the low-dose scanning group. All these indicators had significant differences between these two groups (P < 0.001). The image noises were (17.67 +/- 3.24) HU in standard-dose group and (31.61 +/- 9.42) HU in low-dose group (P < 0.001). As shown by different postprocessing techniques, the median score of the standard-dose group and the low-dose group were 4.52 and 4.78, respectively, which was not significantly different (P = 0.92).
Conclusion: The low-dose CT scanned with 20 mAs effective tube current can remarkably reduce the radiation dose, and provide satisfactory postprocessing images for diagnosis.