Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
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A Phantom Study for the Optimal Low-dose Protocol in Chest Computed Tomography Examination

흉부 전산화단층촬영검사를 위한 최적의 저선량 프로토콜에 관한 팬텀연구

  • Kim, Young-Keun (Dept. of Radiologic Technology, Gwangju Health University) ;
  • Yang, Sook (Industrial Researcher of Cusmedi Co. Ltd) ;
  • Wang, Tae-uk (Dept. of Radiology, Chonnam National University Hwasun Hospital) ;
  • Kim, Eun-Hye (Department of Health Safety Convergence Science, Korea University)
  • 김영근 (광주보건대학교 방사선과) ;
  • 양숙 ((주)커스메디 기업부설연구소) ;
  • 왕태욱 (화순전남대학교병원 영상의학과) ;
  • 김은혜 (고려대학교 보건안전융합과학과)
  • Received : 2021.04.15
  • Accepted : 2021.04.28
  • Published : 2021.04.30
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Abstract

The purpose of this study was to evaluate optimal CT scan parameters to minimize patient dose to the irradiation and maintain satisfactory image quality in low-dose chest computed tomography (CT) scans. In a chest anthropomorphic phantom, chest CT scans were performed at different kVp and mA within reference of 3.4mGy in volume CT Dose Index (CTDIvol). The following quantitative parameters had been statistically evaluated: image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM). Nine radiographers conducted the blind test to select the optimal kVp-mA combination. Results indicated that the kVp-mA combination of 80kVp-90mA, 100kVp-50mA, 120kVp-30mA and 140kVp-30mA were obtained high SNR and CNR. The 120kVp-30mA combination offered good compromise in the FOM, which showed the quality and dose performance. In the blind test, an image of 80kVp-90mA obtained a high score with 4.7 points, and 120kVp-10mA or 140kVp-10mA with a low tube current were observed severe noise and poor image quality, thus resulting in decreased diagnostic accuracy. On the other hand, in the combination of high kVp and high mA(140kVp-90mA), the image quality was improved, but the radiation dose was also increased. the FOM value of 140kVp-90mA was lower than 120kVp-30mA. The application of appropriate scan parameters in low-dose chest CT scans produced satisfactory results in dose and image quality for the accuracy of the clinical diagnosis.

Keywords

Acknowledgement

This research was supported by the research grant of the Gwangju Health University in 2019(2019014).

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