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Development of Image Reconstruction Algorithm for Chest Digital Tomosynthesis System (CDT) and Evaluation of Dose and Image Quality

흉부 디지털 단층영상합성 시스템의 영상 재구성 알고리즘 개발 및 선량과 화질 평가

  • Kim, Min Kyoung (Dept. of Radiological Science, Eulji University) ;
  • Kwak, Hyeng Ju (Dept. of Radiological Science, Eulji University) ;
  • Kim, Jong Hun (Dept. of Radiological Science, Eulji University) ;
  • Choe, Won-Ho (Dept. of Radiological Science, Eulji University) ;
  • Ha, Yun Kyung (Dept. of Radiological Science, Eulji University) ;
  • Lee, So Jung (Dept. of Radiological Science, Eulji University) ;
  • Kim, Dae Ho (Dept. of Radiological Science, Eulji University) ;
  • Lee, Yong-Gu (Dept. of Radiological Science, Hallym Polytechnic University) ;
  • Lee, Youngjin (Dept. of Radiological Science, Eulji University)
  • 김민경 (을지대학교 방사선학과) ;
  • 곽형주 (을지대학교 방사선학과) ;
  • 김종훈 (을지대학교 방사선학과) ;
  • 최원호 (을지대학교 방사선학과) ;
  • 하연경 (을지대학교 방사선학과) ;
  • 이소정 (을지대학교 방사선학과) ;
  • 김대호 (을지대학교 방사선학과) ;
  • 이용구 (한림성심대학교 방사선과) ;
  • 이영진 (을지대학교 방사선학과)
  • Received : 2016.07.11
  • Accepted : 2016.08.29
  • Published : 2016.09.25

Abstract

Recently, digital tomosynthesis system (DTS) has been developed to reduce overlap using conventional X-ray and to overcome high patient dose problem using computed tomography (CT). The purpose of this study was to develop image reconstruction algorithm and to evaluate image characteristics and dose with chest digital tomosynthesis (CDT) system. Image reconstruction was used for filtered back-projection (FBP) methods and system geometry was constructed ${\pm}10^{\circ}$, ${\pm}15^{\circ}$, ${\pm}20^{\circ}$, and ${\pm}30^{\circ}$ angular range for acquiring phantom images. Image characteristics carried out root mean square error (RMSE) and signal difference-to-noise ratio (SDNR), and dose is evaluated effective dose with ${\pm}20^{\circ}$ angular range. According to the results, the phantom image with slice thickness filter has superb RMSE and SDNR, and effective dose was 0.166 mSv. In conclusion, we demonstrated usefulness of developed CDT image reconstruction algorithm and we constructed CDT basic output data with measuring effective dose.

최근 디지털 단층영상합성 시스템 (digital tomosynthesis system, DTS)은 일반 X-ray의 영상 중첩현상과 전산화단층촬영장치 (computed tomography, CT)의 높은 선량의 문제점을 해결하기 위하여 개발되었다. 본 연구의 목적은 흉부 촬영용 디지털 단층영상합성 시스템 (chest digital tomosynthesis, CDT)의 재구성 알고리즘 개발 및 화질과 선량 평가를 수행하는 것이다. 영상의 재구성은 필터 후 역투영 (filtered back-projection, FBP)을 모델링하였고, 팬텀 영상을 획득하기 위한 X-선과 검출기 사이의 각도를 ${\pm}10^{\circ}$, ${\pm}15^{\circ}$, ${\pm}20^{\circ}$, 그리고 ${\pm}30^{\circ}$로 구성하였다. 영상의 화질 평가는 평균 제곱근 편차 (root mean square error, RMSE)와 신호대 잡음 변화율 (signal difference-to-noise ratio, SDNR)로 수행하였고, 선량 평가는 ${\pm}20^{\circ}$의 범위에서 유효선량으로 수행하였다. 결과적으로, 모든 각도에서 Slice thickness 필터를 적용한 팬텀영상이 가장 우수한 RMSE와 SDNR 결과를 나타내었고, 최종 유효 선량은 0.166 mSv로 측정되었다. 결론적으로, 개발한 CDT 재구성 알고리즘의 유용성을 증명하였고, 최종 유효 선량을 측정하여 CDT의 기초 실험 데이터를 구축할 수 있었다.

Keywords

References

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