Purpose: In the last years, dual-energy CT imaging has shown clinical value, thanks to its ability to differentiate materials based on their atomic number and to exploit different properties of images acquired at two different energies. C-arm CT systems are used to guide procedures in the interventional suite. Until now, there are no commercially available systems that employ dual-energy material decomposition. This paper explores the feasibility of implementing a fast kV-switching technique on a clinically available angiographic system for acquiring dual-energy C-arm CT images. Methods: As an initial proof of concept, a fast kV-switching approach was implemented on an angiographic C-arm system and the peak tube voltage during 3D rotational scans was measured. The tube voltage measurements during fast kV-switching scans were compared to corresponding measurements on kV-constant scans. Additionally, to prove stability of the requested exposure parameters, the accuracy of the delivered tube current and pulse width were also recorded and compared. In a first phantom experiment, the voxel intensity values of the individual tube voltage components of the fast kV-switching scans were compared to their corresponding kV-constant scans. The same phantom was used for a simple material decomposition between different iodine concentrations and pure water using a fast kV-switching protocol of 81 and 125 kV. In the last experiment, the same kV-switching protocol as in the phantom scan was used in an in vivo pig study to demonstrate the clinical feasibility. Results: During rapid kV-switching acquisitions, the measured tube voltage of the x-ray tube during fast switching scans has an absolute deviation of 0.23 ?0.13 kV compared to the measured tube voltage produced during kV-constant acquisitions. The stability of the peak tube voltage over different scan requests was about 0.10 kV for the low and 0.46 for the high energy kV-switching scans and less than 0.1 kV for kV-constant scans, indicating slightly lower stability for kV-switching scans. The tube current resulted in a relative deviation of -1.6% for the low and 6.6% overestimation for the high tube voltage of the kV-switching scans compared to the kV-constant scans. The pulse width showed no deviation for the longer pulse width and only minor deviations (0.02 ? 0.02 ms) for the shorter pulse widths compared to the kV-constant scans. The phantom experiment using different iodine concentrations showed an accurate correlation (R2< 0.99) between the extracted intensity values in the kV-switching and kV-constant reconstructed volumes, and allows for an automatic differentiation between contrast concentration down to 10% (350 mg/ml iodine) and pure water under low-noise conditions. Preliminary results of iodine and soft tissue separation showed also promising results in the first in vivo pig study. Conclusions: The feasibility of dual-energy imaging using a fast kV-switching method on an angiographic C-arm CT system was investigated. Direct measurements of beam quality in the x-ray field demonstrate the stability of the kV-switching method. Phantom and in vivo experiments showed that images did not deviate from those of corresponding kV-constant scans. All performed experiments confirmed the capability of performing fast kV-switching scans on a clinically available C-arm CT system. More complex material decomposition tasks and postprocessing steps will be part of future investigations.
KSP 제안 키워드
10 kV, Atomic number, Automatic Differentiation, C-arm CT, CT image, CT imaging, CT system, Complex material, Direct measurements, Energy material, Fast switching
저작권정책 안내문
한국전자동신연구원 지식공유플랫폼 저작권정책
한국전자통신연구원 지식공유플랫폼에서 제공하는 모든 저작물(각종 연구과제, 성과물 등)은 저작권법에 의하여 보호받는 저작물로 무단복제 및 배포를 원칙적으로 금하고 있습니다. 저작물을 이용 또는 변경하고자 할 때는 다음 사항을 참고하시기 바랍니다.
저작권법 제24조의2에 따라 한국전자통신연구원에서 저작재산권의 전부를 보유한 저작물의 경우에는 별도의 이용허락 없이 자유이용이 가능합니다. 단, 자유이용이 가능한 자료는 "공공저작물 자유이용허락 표시 기준(공공누리, KOGL) 제4유형"을 부착하여 개방하고 있으므로 공공누리 표시가 부착된 저작물인지를 확인한 이후에 자유이용하시기 바랍니다. 자유이용의 경우에는 반드시 저작물의 출처를 구체적으로 표시하여야 하고 비영리 목적으로만 이용이 가능하며 저작물을 변형하거나 2차 저작물로 사용할 수 없습니다.
<출처표시방법 안내> 작성자, 저작물명, 출처, 권호, 출판년도, 이용조건 [예시1] 김진미 외, "매니코어 기반 고성능 컴퓨팅을 지원하는 경량커널 동향", 전자통신동향분석, 32권 4호, 2017, 공공누리 제4유형 [예시2] 심진보 외, "제4차 산업 혁명과 ICT - 제4차 산업 혁명 선도를 위한 IDX 추진 전략", ETRI Insight, 2017, 공공누리 제 4유형
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