Evaluation of Image Quality in Low Tube-Voltage Chest CT Scan

흉부 CT 검사 시 저 관전압 영상의 화질평가에 관한 연구

  • Kim, Hyun-Ju (Department of Radiology, Soonchunhyang University. Bucheon Hospital) ;
  • Cho, Jae-Hwan (Department of Diagnostic Radiological Technology, Gyeongsan University College) ;
  • Park, Cheol-Soo (Department of Diagnostic Radiological Technology, Hanlym College)
  • 김현주 (순천향대학교 부천병원 영상의학과) ;
  • 조재환 (경산1대학 방사선과) ;
  • 박철수 (한림 성심 대학 방사선과)
  • Received : 2010.05.13
  • Accepted : 2010.12.03
  • Published : 2010.12.30

Abstract

Purpose : The patients who visited this department for pulmonary disease and need CT scans for Follow-up to observe change of CT value, evaluation of image quality and decrease of radiation dose as change of kVp. Subjects and Methods : Subjects were the patients of 20 persons visited this department for pulmonary disease and Somatom Sensation 16(Semens, Enlarge, Germany) was used. Measurement of CT value as change of kVp was done by setting up ROI diameter of 1cm at the height of thyroid, aortic arch, right pulmonary artery in arterial phase image using 100 kVp, measuring 3 times, and recorded the average. CT value of phantom was measured by scanning phantoms which means contrast media diluted by normal saline by various ratio with tube voltage of 80 kVp, 100 kVp, 120 kVp, 140 kVp and recorded the average of 3 CT values of center of phantom image. In analysing radiation dose, CTDIVOL values of the latest arterial phase image of 120 kVp and as this research set that of 100 kVp were analyzed comparatively. 2 observers graded quality of chest images by 5 degrees (Unacceptable, Suboptimal, Adequate, Good, Excellent). Results : CT value of chest image increased at 100 kVp by 14.06%~27.26% in each ROI than 120 kVp. CT value of phantom increased as tube voltage lowered at various concentration of contrast media. CTDIVOL decreased at 100 kVp(5.00 mGy) by 36% than 120 kVp(7.80 mGy) in radiation dose analysis. here were 0 Unacceptable, 1 Suboptimal, 3 Adequate, 10 Good, 6 Excellent in totally 20 persons. Conclusion : Chest CT scanning with low kilo-voltage for patients who need CT scan repeatedly can bring images valuable for diagnose, and decrease radiation dose against patients.

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