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Changes of Radiation Dose and Image Quality Due to Additional Filtration Material in Computed Radiography  

Kwon, Soon-Mu (Department of Radiological Science, The Graduate School of Catholic University of Daegu)
Cho, Hyung-Wook (Department of Radiological Science, The Graduate School of Catholic University of Daegu)
Kang, Yeong-Han (Department of Radiology, Catholic University Hospital of Daegu School of Medicine)
Kim, Boo-Soon (Department of Radiologicic Technology, Daegu Health College)
Kim, Jung-Su (Department of Bio-convergence Engineering, Korea University Graduate School)
Publication Information
Journal of radiological science and technology / v.37, no.4, 2014 , pp. 239-246 More about this Journal
Abstract
Filter absorbs low-energy X-ray to increase the average energy and reduces patient exposure dose. This study investigates if the materials of Mo and W could be used for the digital imaging device CR by conducting image assessment and dose measurement of SNR, FOM and histogram. In addition, measurement of beam quality was conducted depending on the material of the filter, and at the same time, a proper combination of filters was examined depending on the change in tube voltage (kVp). In regard to entrance skin dose, Mo filter showed the dose reduction by 42~56%, compared to Cu filter. Moreover, Mo filter showed higher transmission dose by around 1.5 times than that of Cu filter. In image assessment, it was found that W was unsuitable to be used as a filter, whereas Mo could be used as a filter to reduce dose without decline in image quality at the tube voltage of 80 kVp or higher. As tube voltage increased, 2.0 mm Al+0.1 mm Mo almost had a similar histogram width to that of 2.0 mm Al+0.2 mm Cu. Therefore, Mo filter can be used at relatively high tube voltage of 80 kVp, 100 kVp and 120 kVp. The SNR of 2.0 mm Al+0.1 mm Mo did not show any significant difference from those of 2.0 mm Al+0.2 mm Cu and 2.0 mm Al+0.1 mm Cu. As a result, if Mo filter is used to replace Cu filter in general radiography, where 80 kVp or higher is used for digital radiation image, patient exposure dose can be reduced significantly without decline in image quality, compared to Cu filter. Therefore, it is believed that Mo filter can be applied to chest X-ray and high tube voltage X-ray in actual clinical practice.
Keywords
Mo filter; Cu filter; image assessment; patient exposure dose;
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Times Cited By KSCI : 1  (Citation Analysis)
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