Radiation Dose Reduction for High Resolution Spectral Breast CT Using Tensor-Framelet Based Iterative Reconstruction
B Zhao1*, h ding2, H Gao3, S Molloi4, (1) University of California, Irvine, Irvine, CA, (2) ,,,(3) Emory University, Atlanta, GA, (4) University of California, Irvine, CASU-D-116-3 Sunday 2:05PM - 3:00PM Room: 116
To investigate the feasibility of dose reduction using tensor-framelet based iterative reconstruction (TFIR) method for a dedicated high resolution spectral breast computed tomography (CT).
A simulation study was conducted with a phantom of 14 cm in diameter for a high resolution breast CT system based on an energy-resolved photon-counting Si strip detector with 0.1 mm pixel size. The modulation transfer function (MTF) calculated from images reconstructed by TFIR and FBP with simulation data was compared to the measured detector MTF. In the experimental study, a water phantom of 16 mm in diameter with Al wires of various diameters and a polyethylene (PE) plastic phantom of 13 mm in diameter with three water filled holes of 1, 2 and 3 mm were imaged with 1229 projections over 360° during a CT scan. The images were reconstructed by filtered back projection (FBP) and by TFIR with various projection undersampling ratio and the image quality between these two methods was compared. The spatial resolution was evaluated using Al wires of various diameters and the contrast to noise ratio (CNR) was evaluated using the PE phantom.
The MTFs calculated from the simulated large phantom images reconstructed by TFIR and FBP are comparable to the measured detector MTF. The spatial resolution was comparable for the images reconstructed by TFIR with 204 projections and by FBP with 614 projections. There was a slight in CNR using TFIR with 204 projections.
The radiation dose of a high resolution spectral breast CT system is reduced by 67% by the TFIR technique without any reduction in the image quality. Therefore, TFIR can potentially be used for a high resolution spectral breast CT system to reduce the radiation dose for breast screening.
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