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Resolution and noise trade‐off analysis for volumetric CT
Author(s) -
Li Baojun,
Avinash Gopal B.,
Hsieh Jiang
Publication year - 2007
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2779128
Subject(s) - imaging phantom , noise (video) , image resolution , context (archaeology) , iterative reconstruction , kernel (algebra) , rotation (mathematics) , image noise , noise power , optics , resolution (logic) , computer science , physics , algorithm , mathematics , computer vision , artificial intelligence , power (physics) , image (mathematics) , paleontology , combinatorics , quantum mechanics , biology
Until recently, most studies addressing the trade‐off between spatial resolution and quantum noise were performed in the context of single‐slice CT. In this study, we extend the theoretical framework of previous works to volumetric CT and further extend it by taking into account the actual shapes of the preferred reconstruction kernels. In the experimental study, we also attempt to explore a three‐dimensional approach for spatial resolution measurement, as opposed to the conventional two‐dimensional approaches that were widely adopted in previously published studies. By scanning a finite‐sized sphere phantom, the MTF was measured from the edge profile along the spherical surface. Cases of different resolutions (and noise levels) were generated by adjusting the reconstruction kernel. To reduce bias, the total photon fluxes were matched: 120 kVp , 200 mA , and 1 s per gantry rotation. All data sets were reconstructed using a modified FDK algorithm under the same condition: Scan field‐of‐view( SFOV ) = 10 cm , and slice thickness = 0.625 mm . The theoretical analysis indicated that the variance of noise is proportional to > 4 th power of the spatial resolution. Our experimental results supported this conclusion by showing the relationship is 4.6th (helical) or 5th (axial) power.