S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Radiation Applied Life Science (대학원 협동과정 방사선응용생명과학전공) Theses (Ph.D. / Sc.D._협동과정 방사선응용생명과학전공)
Material Decomposition with the Multi-Energy Attenuation Coefficient Ratio by Using a Multiple Discriminant Analysis
멀티에너지 감쇠계수 비의 다중판별분석법을 이용한 물질분해
- 의과대학 협동과정 방사선응용생명과학전공
- Issue Date
- 서울대학교 대학원
- Photon counting detector; Multi-energy (spectral) CT; Multiple discriminant analysis (MDA); Material decomposition; Concentration quantification
- 학위논문 (박사)-- 서울대학교 대학원 : 방사선응용생명과학전공, 2016. 8. 이원진.
- Purpose: The objective of this study was to develop a spectral CT system using a photon counting detector, and to decompose materials by applying multiple discriminant analysis (MDA) to the energy-dependent attenuation coefficient ratios.
Methods: I imaged cylindrical phantoms of PMMA with four holes filled with calcium chloride, iodine, and gold nanoparticle contrast agents. The attenuation coefficients were measured via reconstructed multi-energy images, and the linear attenuation ratio was used for material identification. The MDA projection matrix, determined from training phantoms, was used to identify the four materials in testing phantoms. For quantification purposes, relationships between attenuation coefficients at multiple energy bins and concentrations were characterized by the least square method for each material.
Results: The mean identification accuracy for each of the three materials was 0.94±0.03 for iodine, 0.96±0.02 for gold nanoparticle, and 0.92±0.05 for calcium chloride. The mean quantification errors were 1.90±1.58% for iodine, 3.85±3.13% for gold nanoparticle, and 3.40±2.62% for calcium chloride.
Conclusions: The developed multi-energy CT system based on the photon-counting detector with MDA can precisely decompose the four materials.