Speaker: Qiulin Tang

Title: Analytic Reconstruction for Single Photon Emission Computed Tomography

Abstract: This dissertation concentrates on improving analytical reconstruction algorithms for single photon emission computed tomography (SPECT). In SPECT imaging, photon attenuation within the body is a major factor contributing to the quantitative inaccuracy in measuring the distribution of radioactivity. Thus, attenuation compensation is a major goal in SPECT development. Among 2D parallel-beam image reconstruction methods, Metz and Pan¡'s 2D parallel-beam quasi-optimal method has superior noise properties. In this dissertation, analytical fan-beam and cone-beam algorithms are developed by extending Metz and Pan¡'s parallel-beam quasi-optimal method. It is shown that these new algorithms also have good noise properties. This dissertation also develops an image reconstruction algorithm for data acquisition based on Metz and Pan¡'s quasi-optimal method. This algorithm reconstructs the image with parallel-beam projection data acquired over a view range.

In cone-beam planar-trajectory imaging, axial artifacts result from incomplete projection data. A skew-slit collimator system, which is a generalized cone-beam system, is introduced to reduce the axial artifacts without decreasing the transaxial spatial resolution. An image reconstruction algorithm is developed for this skew-slit system. This algorithm also has good noise properties, because it is based on Metz and Pan¡'s quasi-optimal method.