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Keywords:
Radioprotection / Radiation dose, Lung, CT, CT-Quantitative, Experimental investigations, Comparative studies, Technology assessment
Authors:
J. H. Kim, K. B. Lee; Seoul/KR
DOI:
10.1594/ecr2015/C-0891
Aims and objectives
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 on manufacturers is different,
but it is common using information of patient like shape,
size,
density and data obtained during scan.
Each name of this function is called by different way but the same object is to decrease of radiation dose.
A recent research shows that automatic exposure control can reduce 20~40% of radiation dose.
However,
in 2007,
Jianhai Li reveals that misusage of this function results in an increase of tube current and image noise.
Recently,
there are almost no CT examinations that don't use automatic exposure control.
However,
there are some cases of CT examinations that underwent without fully scanned scout image because of an overestimation of auto exposure control or shortage of time,
or laziness.
In this study,
we performed phantom studies to investigate changes of tube current by setting a poor topogram(scout image) that doesn't include entire scan range.