Alexander Whitehead & Robert Twyman Skelly - CMIC/WEISS Joint Seminar Series

Speaker: Alexander Whitehead

Title:  Motion Modelling for PET data

Abstract: 

Motion correction is imperative to the reduction of blurring and artefacts inherent in PET; due to the relatively long acquisition time, and the temporal difference in the attenuation map acquisition. Methods of motion correction include gated reconstruction, where the acquisition is binned, based on a respiratory trace. To acquire these respiratory traces, an external device, like the Real Time Position Management System, or a data driven method, such as PCA, can be used. However, data driven methods have the disadvantage that they are adversely affected by the tracer kinetics of a dynamic acquisition. I will discuss a method to motion correct PET and align it to a CT incorporating an initial MLACF reconstruction with several other improvements, including fitting a motion model on low noise low temporal/gate resolution data, and applying it to high noise high temporal/gate resolution data. Additionally, I will discuss several adaptions of the PCA method, through which it can be used with dynamic data.

Speaker: Robert Twyman Skelly

Title:  Stochastic Optimisation Methods Applied to PET Image Reconstruction

Abstract: 

Subsets are often used in PET iterative image reconstruction algorithms to accelerate convergence. However, convergence rate can slow and inter-update fluctuations in image voxel values can occur. I will discuss the work to apply a novel class of stochastic variance reduction algorithms to PET reconstruction that reduces the reliance on hyper-parameter selection, allows for faster convergence and reduces the impact of subset induced inter-update voxel value fluctuations.

Chair: Kris Thielemans