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TU‐A‐201B‐03: Dose Reduction and Image Quality Benefits Using Model Based Iterative Reconstruction (MBIR) Technique for Computed Tomography
Author(s) -
Yadava G,
Kulkarni S,
Colon Z Rodriguez,
Thibault J,
Hsieh J
Publication year - 2010
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 - 10.1118/1.3469177
Subject(s) - iterative reconstruction , image quality , imaging phantom , image noise , image resolution , medical imaging , nuclear medicine , noise (video) , tomography , artifact (error) , artificial intelligence , computer science , computer vision , image (mathematics) , medicine , radiology
Purpose : To demonstrate the image‐quality benefits and potential for significant dose reduction with Model‐Based Iterative Reconstruction (MBIR) technique incorporating physical model of computed tomography (CT) systems. Method and Materials : A model based iterative reconstruction (MBIR), a maximum a posteriori (MAP) estimate with edge‐preserving prior, has been developed for x‐ray CT image reconstruction. It utilizes a more accurate physical model of the imaging chain accounting for system‐optics, noise and non‐idealities in the data, hence improves image quality compared to conventional filtered backprojection (FBP) at significantly reduced dose levels. In this work, a GE multi‐slice CT system was used to acquire a set of multi‐dose data and standard FBP reconstruction. For resolution assessment, a Catphan600® phantom was scanned at three dose levels (40, 20, and 10 mGy with 120kVp spectrum), and images were reconstructed using two methods: FBP with ASiR, and the MBIR. For artifact and image‐quality evaluations, an anthropomorphic CT abdomen phantom (Kyoto Kagaku Co., Ltd) was scanned at four dose levels (120kVp spectrum with 225, 112, 54, and 27 mAs), and a comparative image‐quality study between standard FBP and MBIR in slice and multi‐planar reformat (MPR) modes was made. In addition, few clinical case studies were also used to compare the imaging performance in actual clinical data. Results : From the resolution study, we found that even at 1/4 th dose, MBIR images have improved resolution at significantly reduced noise compared to standard state‐of‐the‐art FBP with ASiR. Use of ASIR provides up to 50% dose reduction with equivalent FBP image‐quality. For anthropomorphic phantom, even below 1/8 th dose, MBIR images outperformed the corresponding FBP images in both, slice and MPR modes, demonstrating immense potential for dose reduction, yet improved image quality, in clinical CT. Conclusion : Results of the MBIR method demonstrated significant potential for dose reduction and image‐quality improvements in clinical CT.