Date of Award
Master of Science (MS)
In order to transition the GPU-accelerated CT reconstruction algorithm to a more clinical environment, a graphical user interface is implemented. Some optimization methods on the implementation are presented. We describe the alternating minimization (AM) algorithm as the updating algorithm, and the branchless distance-driven method for the system forward operator. We introduce a version of the Feldkamp-Davis-Kress algorithm to generate the initial image for our alternating minimization algorithm and compare it to a choice of a constant initial image. For the sake of better rate of convergence, we introduce the ordered-subsets method, find the optimal number of ordered subsets, and discuss the possibility of using a hybrid ordered-subsets method. Based on the run-time analysis, we implement a GPU-accelerated combination and accumulation process using a Hillis-Steele scan and shared memory. We then analyze some code-related problems, which indicate that our implementation of the AM algorithm may reach the limit of single precision after approximately 3,500 iterations. The Hotelling observer, as an estimation of the human observer, is introduced to assess the image quality of reconstructed images. The estimation of human observer performance may enable us to optimize the algorithm parameters with respect to clinical use.
Joseph A. O’Sullivan
Joseph A. O’Sullivan David G. Politte Ulugbek Kamilov