CT 검사 시 관전류 자동조절기법이 선량에 미치는 영향

Abstract

In this study, the automatic exposure control (AEC) modes of tube current (SIEMENSCareDose 4D and GE AEC mode) that CT manufacturers are using was applied to neck, chestand abdomen in order to determine the difference in the respective dose parameters (CTDIvol,DLP and mSv) resulting from the dose reduction. Equipment in use at C university adopted CareDose 4D of Siemens and AEC mode of General Electric (GE), and the x-ray exposure conditionswere adjusted to be as identical as possible between the experiments. For the assessment of thedose reduction, the differences between the doses with and without the use of the tube currentAEC mode by the respective manufacturer were measured for each body part including neck,chest and abdomen of a human phantom, Rando Phantom (Art-200x, Fluke Biomedical, USA). First, the assessment of SIEMENS-Care Dose 4D yielded the following results. At the neck, theautomatic exposure control resulted in a 3.3% reduction in CTDIvol and DLP, and a 3% reductionin the effective dose, mSv, compared to manual exposure control. The automatic exposure controlat the chest displayed the reduction in CTDIvol and DLP by 25.5%, and in the effective dose, mSv,by 25.4% compared to the manual exposure control. In case of abdomen, CTDIvol and DLP wereshown to be reduced by 16%, and the effective dose (mSv) by 16.3% under the automatic exposurecontrol compared to the manual exposure. Second, the assessment results of GE AEC mode are asfollows. The automatic exposure control at the neck resulted in a 45.1% reduction in CTDIvol andDLP, and a 44.7% reduction in the effective dose (mSv) in comparison to the manual exposurecontrol. At the chest, the automatic exposure control displayed a 47.6% reduction in CTDIvoland DLP, and a 47.5% reduction in the effective dose, mSv, compared to the manual exposurecontrol. At the abdomen, it was shown that CTDIvol and DLP were reduced by 26.9%, and theeffective dose (mSv) by 26.8% under the automatic exposure control compared to the manualexposure. The assessment results of the two automatic exposure control modes of tube current at each part (neck, chest and abdomen) of a Rando Phantom thus suggested that the effective dose(mSv), CTDIvol and DLP were reduced in the AEC mode compared to the manual control, andthe radiation dose to patients could be significantly reduced via the use of the AEC mode.