單光子發射斷層掃描是將放射性藥物注射入生物體，並利用各種組織器官對於藥物的吸收反應程度不同，而對組織器官進行功能性的分析。將針孔成像原理與單光子發射斷層掃描加以結合，利用針孔成像的放大原理，可以得到高解析度影像。過去在臨床上使用在針孔單光子發射斷層掃描的影像重建方法是濾波反投影法(Filtered Back Projection, FBP)，濾波反投影法雖是臨床上普遍使用的影像重建法，但是其本身的特性限制了重建影像的品質，會在重建影像中產生放射狀假影。本研究使用以統計為基礎的光子偵收模型，對於針孔成像的幾何特性進行分析，再配合硬體設計上的旋轉，用疊代式影像重建演算法(Iterative Image Reconstruction Algorithm)進行影像重建，希望在具有理論基礎的成像系統與演算法的配合下，以相同的偵檢條件，得到高品質的影像。實驗結果顯示，將統計成像原理運用在針孔的放大系統中，重建影像無論在位置、影像值、均勻性與邊界保留上，皆能順利的重建出全三維的高解析度高品質影像。對於需要高品質影像的小型動物實驗而言，本研究結果提供了適用於進行定性與定量分析的影像。

Pinhole imaging can produce high-resolution image results due to its geometric characteristics. Combined with a single photon emission computed tomography (SPECT), pinhole SPECT becomes a powerful functional imaging tool for small animals or in vivo objects. Conventionally, SPECT imaging used filtered back projection (FBP) method for image reconstruction. Although the FBP method is frequently used in clinics, the reconstructed images with FBP still have some unfavorable problems such as artifacts. In this work, we describe a fully three-dimensional statistical model for SPECT data, and develop a fast iterative image reconstruction algorithm. We combine the real pinhole geometry and statistical image reconstruction algorithm to obtain high quality image. The results in simulation experiments show that the reconstructed images have nice properties in maintaining accuracy of tracer uptake, image uniformity, and positions of point source and edges. The proposed pinhole SPECT imaging method can produce high quality three-dimensional image for the small animal studies.

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