TY - JOUR
T1 - Method to calculate frequency characteristics of reconstruction filter kernel in X-ray computed tomography
AU - Sato, Kazuhiro
AU - Tomita, Yu
AU - Kageyama, Ryota
AU - Takane, Yumi
AU - Kayano, Shingo
AU - Saito, Haruo
N1 - Funding Information:
This work was supported by JSPS KAKENHI Grant Number JP17K10391.
Publisher Copyright:
© 2019, Australasian College of Physical Scientists and Engineers in Medicine.
PY - 2019
Y1 - 2019
N2 - A computed tomography (CT) image is generally reconstructed by a filtered back projection (FBP) algorithm. In an FBP algorithm, the image quality primarily depends on a reconstruction filter kernel. Although the details of the filter kernel are not disclosed to users, the frequency response of the filter kernel can theoretically be calculated using the relational formula of the filter kernel and the modulation transfer function (MTF) of the reconstruction algorithm (MTFA). In this study, we proposed a method to determine the frequency response of a filter kernel and verify its validity. Two clinical CT scanners were used to derive the filter kernel. The MTF was obtained and subsequently separated to the MTF of the scanner system and MTFA. Using the relational formula of the filter kernel and MTFA, we calculated the frequency response of the filter kernel. To verify the calculated result, we measured the noise power spectrum (NPS). Additionally, the filter kernel was calculated using the relational formula of the filter kernel and NPS. In both CT scanners, the filter kernels calculated by the two methods showed good agreement, and we confirmed the validity of the results and the effectiveness of the proposed method. Furthermore, the inherent image quality performance of the CT scanner could be clarified by the reconstruction filter kernel.
AB - A computed tomography (CT) image is generally reconstructed by a filtered back projection (FBP) algorithm. In an FBP algorithm, the image quality primarily depends on a reconstruction filter kernel. Although the details of the filter kernel are not disclosed to users, the frequency response of the filter kernel can theoretically be calculated using the relational formula of the filter kernel and the modulation transfer function (MTF) of the reconstruction algorithm (MTFA). In this study, we proposed a method to determine the frequency response of a filter kernel and verify its validity. Two clinical CT scanners were used to derive the filter kernel. The MTF was obtained and subsequently separated to the MTF of the scanner system and MTFA. Using the relational formula of the filter kernel and MTFA, we calculated the frequency response of the filter kernel. To verify the calculated result, we measured the noise power spectrum (NPS). Additionally, the filter kernel was calculated using the relational formula of the filter kernel and NPS. In both CT scanners, the filter kernels calculated by the two methods showed good agreement, and we confirmed the validity of the results and the effectiveness of the proposed method. Furthermore, the inherent image quality performance of the CT scanner could be clarified by the reconstruction filter kernel.
KW - Computed tomography
KW - Image reconstruction
KW - Modulation transfer function
KW - Noise power spectrum
KW - Reconstruction filter kernel
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U2 - 10.1007/s13246-019-00819-5
DO - 10.1007/s13246-019-00819-5
M3 - Article
C2 - 31755031
AN - SCOPUS:85075361496
JO - Australasian Physical and Engineering Sciences in Medicine
JF - Australasian Physical and Engineering Sciences in Medicine
SN - 0158-9938
ER -