Due to development of MDCT, Computed tomography is taking major role in diagnostic area. Good resolution and short examination time is major advantage of CT in medical environment where speed is virtue. However, radiation dose of CT is inevitable because CT is performed by X-ray. In this reason, scanner manufacturers develop and commercialize various functions to reduce radiation dose and to make optimized images. Automatic exposure control that adapts radiation dose to size and shape of patient is one of those functions. This method depending...

128 MDCT scanners that used in this study are Somatom Definition AS+(Siemens, Erlangen, Germany) and Optima 660(GE healthcare, US), Ingenuity(Philips, Netherlands). A Lung/Chest Phantom of model RS-330(Fluke Biomedical, USA) was used. Scan parameters of the chest examination protocol on each scanner are recommended. All scan data are obtained with each automatic exposure control mode(Caredose4D in Somatom Definition AS+, Auto mA in Optima 660, iDose in Ingenuity). Scan parameters of Siemens scanner are 120kV, 200mAs of reference image quality and that of GE scanner is 120kV,...

1. Pattern of change in mAs according to types of topogram Scan data from topogram that has no information above shoulder level(shoulder cut) shows high mAs than that from normal topogram in 3 types of scanner. In contrast to shoulder cut, the usage of a topogram that has no information below lower lobes of lung(liver cut) decreases mAs compared with scan data using normal topogram in 3 types of scanner. In two cases of scan data from abnormal topogram, there are no significant change in...

Radiation exposure due to CT examinations takes 11% in total radiation dose of medical area and take 67% of total radiation dose in population[3]. In these reasons, radiation dose of CT is long-standing issue. Manufacturers of CT have been made effort to reduce radiation exposure by developing various technologies, AEC is also developing in same way. Usefulness of AEC system was proved by advanced studies. Lehmann KJ showed rotational AEC can reduce radiation dose almost 20% with information about geometrical structure of patient[11]. In phantom...

Jung Hoon Kim, Radiological Technologist Department of Radiology, Seoul Asan Medical Center, Seoul, Korea [email protected] Ki Baek Lee, Radiological Technologist Department of Radiology, Seoul Asan Medical Center, Seoul, Korea [email protected]

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