正子斷層掃描統計影像重建的階層式貝氏OSL演算法

A Hierarchical Bayesian OSL Algorithm for Positron Emission Tomography Statistical Image Reconstruction

陳郁緁(Yu-Jie Chen)

指導教授 ： 許文郁

國立清華大學/理學院/統計學研究所/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00223

摘要

正子斷層掃描為現今重要醫學診斷工具之一，而其影像需利用統計方法重建。
本篇論文延續以往利用類似EM 演算法求取最大概似估計量的方式來進行影
像重建。我們提出了一種新的影像重建方法，將階層式貝氏架構與一種改良的
EM 演算法-OSL 演算法相結合，其不僅考慮了相近亮度部位應平滑的概念，更
加入影像之間的權重以避免過度平滑，使影像邊緣得以保留。此種重建法會以
模擬的方式來進行說明並與其他方法比較。

關鍵字

統計影像重建法 ； OSL演算法 ； ICM演算法 ； Gibbs prior ； Hierarchical Bayesian model

並列摘要

Positron Emission Tomography (PET) is one of the most important techniques for
medical diagnosis. The statistical methods are needed in image reconstruction for
PET. In this dissertation we develop a new approach to the reconstruction of the
image. We use hierarchical Bayesian model to describe how the observations are
obtained and apply a modied EM-type approach, the one-step-late algorithm, to
calculate the maximum likelihood estimate for the emission intensity at each pixel.
This method take care of both smoothness and edge eects of the image simulta-
neously. Finally the performance of this method is demonstrated and compared
with other methods by computer simulations.

參考文獻

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[4] JIA-HUNG,TANG, "Hierarchical Bayesian Image Reconstruction for Emis-