UBC Theses and Dissertations
Investigation of problems created in SPECT images by artifacts in the attenuation map and correction methods Chang, Zheng
This thesis consists of five chapters. Chapter 1 presents the basic ideas of SPECT imaging. This chapter also explains the phenomenon of attenuation and shows how the attenuation effect affects SPECT imaging. Chapter 2 reviews various attenuation estimation methods and attenuation compensation methods. The advantages and disadvantages of these methods are discussed in this chapter. Moreover, this chapter discusses three artifacts such as missing counts, truncation and cross-talk effect, and their corrections. Additionally, this chapter presents three map reconstruction methods: FBP, OSEM and OSTGS. OSTGS has been tested by using computer simulations described in Chapter 3. Chapter 3 presents transmission simulations performed analytically. The analytical transmission simulations can be used to simulate simultaneous transmission /emission data acquisition by combining Monte Carlo SLMSET emission simulations. Different reconstruction methods have been tested in this computer simulation and the thorax phantom experiment described in Chapter 4. The results of these tests indicate that the cross-talk correction performance achieved by using OSTGS is better than that achieved by using conventional subtraction cross-talk correction. Finally, a summary is presented in Chapter 5 in which three topics for future work are being discussed.
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