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Effect of nonlinear three‐dimensional optimized reconstruction algorithm filter on image quality and radiation dose: Validation on phantoms
Author(s) -
Bai Mei,
Chen Jiuhong,
Raupach Rainer,
Suess Christoph,
Tao Ying,
Peng Mingchen
Publication year - 2009
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 - 10.1118/1.3030953
Subject(s) - imaging phantom , image quality , iterative reconstruction , image noise , filter (signal processing) , noise (video) , noise reduction , optical transfer function , image resolution , reconstruction filter , mathematics , nuclear medicine , artificial intelligence , computer vision , algorithm , computer science , optics , filter design , image (mathematics) , medicine , physics , root raised cosine filter
A new technique called the nonlinear three‐dimensional optimized reconstruction algorithm filter (3D ORA filter) is currently used to improve CT image quality and reduce radiation dose. This technical note describes the comparison of image noise, slice sensitivity profile (SSP), contrast‐to‐noise ratio, and modulation transfer function (MTF) on phantom images processed with and without the 3D ORA filter, and the effect of the 3D ORA filter on CT images at a reduced dose. For CT head scans the noise reduction was up to 54% with typical bone reconstruction algorithms (H70) and a 0.6 mm slice thickness; for liver CT scans the noise reduction was up to 30% with typical high‐resolution reconstruction algorithms (B70) and a 0.6 mm slice thickness. MTF and SSP did not change significantly with the application of 3D ORA filtering ( P > 0.05 ) , whereas noise was reduced ( P < 0.05 ) . The low contrast detectability and MTF of images obtained at a reduced dose and filtered by the 3D ORA were equivalent to those of standard dose CT images; there was no significant difference in image noise of scans taken at a reduced dose, filtered using 3D ORA and standard dose CT ( P > 0.05 ) . The 3D ORA filter shows good potential for reducing image noise without affecting image quality attributes such as sharpness. By applying this approach, the same image quality can be achieved whilst gaining a marked dose reduction.