TITLE:
Denoising Projection Data with a Robust Adaptive Bilateral Filter in Low-Count SPECT
AUTHORS:
Susumu Nakabayashi, Takashi Chikamatsu, Takao Okamoto, Tatsuro Kaminaga, Norikazu Arai, Shinobu Kumagai, Kenshiro Shiraishi, Takahide Okamoto, Takenori Kobayashi, Jun’ichi Kotoku
KEYWORDS:
Bilateral Filter, Denoising, SPECT, Nuclear Medicine
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.3,
August
20,
2018
ABSTRACT: Low-count SPECT images are
well known to be smoothed strongly by a Butterworth filter for statistical
noise reduction. Reconstructed images have a low signal-to-noise ratio (SNR)
and spatial resolution because of the removal of high-frequency signal
components. Using the developed robust adaptive bilateral filter (RABF), which
was designed as a pre-stage filter of the Butterworth filter, this study was
conducted to improve SNR without degrading the spatial resolution for low-count
SPECT imaging. The filter can remove noise while preserving spatial resolution.
To evaluate the proposed method, we extracted SNR and spatial resolution in a
phantom study. We also conducted paired comparison for
visual image quality evaluation in a clinical study. Results show that SNR
was increased 1.4 times without degrading the spatial resolution. Visual image
quality was improved significantly (p