核子醫學上，兩個主要的分子影像儀器即為單光子斷層造影(SPECT)與正子斷層造影；SPECT與PET空間解析度表現與下列因素有關：SPECT解析度上的限制，在一般情形下主要受限於技術(例：準直儀的設計)；在PET影像，受限兩個物理因素：positron range與non-collinearity，兩者最後限制了系統解析度。
本研究目的為：以蒙地卡羅方式模擬同時結合SPECT與PET優勢的雙光子斷層掃描(DuPECT)。期許能解決PET核種由迴旋加速器製造所造成的高成本與短半衰期等問題，並獲得比SPECT系統上同核種更高的影像解析度。本實驗DuPECT方法使用縫隙(slit)、孔狀型(hole)準直儀搭配同位素Indium-111進行。
In-111核種半衰期為2.8天且衰變時99.995%會放出兩個能量分別為171 keV及245 keV的γ光子，由於縫隙式與孔狀型可以準直放射出的光子並與DuPECT上的同符線路獲得同符事件，即可以數學公式重建出空間一平面與一直線的交點，交點即為影像同位素衰變處。
模擬結果可推測若使用能同時發出雙光子的核種，DuPECT概念即可行。本方法可提供比同核種在SPECT系統下更佳的空間解析度。另能獲得即時影像(real time image)。雖仍有待克服的問題，但DuPECT在未來仍有相當的可能性。

In nuclear medicine, the two major molecular imaging modalities namely are single photon emission tomography (SPECT) and positron emission tomography. Spatial resolution performance in PET and SPECT is related to a number of different factors. A general observation is that improvements in SPECT resolution are effectively only limited by technology (e.g., collimator design), whereas in PET imaging, two physics-related limitations, namely positron range and photon non-collinearity, ultimately limit system resolution.
The purpose of this work is to simulate the application of dual photons computed tomography (DuPECT) which is considered to combine the benefits of SPECT and PET at the same time. It is expected to alter the problem of the high cost of isotopes used in PET. They are generated from the cyclotron and their half-life are too short to use. Also to obtain higher resolution compared to same isotopes in SPECT. The slit, hole collimators and the isotope In-111 were used in the DuPECT method.
In-111 disintegrates and emits two γ photons with 171keV and 245 keV energy by over 99.99%. The data that would be used to reconstruct images by calculating the intersection of a plane and a line is from collimating the emitted photons by slit and hole collimators and obtaining the coincidence by the coincidence circuit in DuPECT system. The intersection is also where the isotope decayed.
The simulation results show that the concept of DuPECT method is feasible if the isotope would emit two photons. The spatial resolution is also better than SPECT. Furthermore, the reconstructed image on DuPECT could be real time image. But there are still some problems. Nevertheless, DuPECT still has lots of possibilities in the future.

第一章 前言 1
1.1背景 1
1.2研究動機與目的 1
1.3論文架構 2
第二章 單光子發射斷層造影與正子斷層造影 3
2.1單光子發射斷層造影(SPECT) 3
2.1.1 SPECT原理 3
2.1.2 準直儀 3
2.2正子斷層造影(PET) 4
第三章 材料與方法 8
3.1 In-111 8
3.2雙光子斷層掃描(DuPECT)原理 10
3.3 實驗步驟 11
3.3.1 GATE 12
3.3.2影像重建公式 15
3.3.3實驗項目 16
3.3.3.1準直儀孔徑大小選擇 16
3.3.3.2點射源在不同位置解析度偵測 18
3.3.3.3雙能窗散射與隨機事件修正 19
3.3.3.4均勻度測試與衰減校正 21
3.3.3.5六角柱孔狀與縫隙準直儀幾何改進與結果 22
3.3.3.6時間窗對隨機事件發生比例探討 24
3.3.3.7閃爍晶體長度探討 24
第四章 結果與討論 25
4.1 準直儀孔徑大小選擇實驗結果 25
4.2 點射源在不同位置解析度偵測結果 27
4.3 雙能窗散射與隨機事件修正結果 33
4.4均勻射源衰減校正結果 35
4.4.1 無衰減校正修正結果 35
4.4.2 有衰減校正修正結果 36
4.5 準直儀幾何改進與結果 38
4.6 時間窗對隨機事件發生比例探討 39
4.7準直儀幾何改進，點射源在不同位置的表現 41
第五章 結論與未來工作 49
5.1結論 49
5.2未來工作 50
第六章 參考文獻 53

Arman R, Habib Z 2008 PET versus SPECT: strengths, limitations and challenges J. Nucl. Med. 29 193-207
Assié K, Vincent B, Irene B, Claude C, Sebastien J, Delphine L and Christian M 2004 Monte Carlo simulation in PET and SPECT instrumentation using GATE Nucl. Instrum. Methods. A 527 180–9
Assié K , I. Gardin, P. Véra and I. Buvat 2005 Validation of the Monte Carlo simulator GATE for indium-111 imaging Phys. Med. Biol. 3113-3125
Carney J P J and Townsend D W 2006 Clinical count rate performance of an LSO PET/CT scanner utilizing a new front-end electronics architecture with sub-nanosecond intrinsic timing resolution Radiation Phys and Chemistry 75 2182-2185
Charles C, Watson, Michael E. Casey, Bernard B, Jonathan P C, David W T, Stefan E, Steve M and Frank P D 2005 Optimizing Injected Dose in Clinical PET by Accurately Modeling the Counting-Rate Response Functions Specific to Individual Patient Scans J Nucl. Med. 45 1825-1834
Dewaraja Y K, Ljungberg M and Koral K. F. 2000 Accuracy of 131I tumor quantification in radioimmunotherapy using SPECT imaging with an ultra-high-energy collimator: Monte Carlo study J. Nucl. Med. 41 1760–7
Di Carli M F and Hachamovitch R 2006 Should PET replace SPECT for evaluating CAD? The end of the beginning. J. Nucl. Cardiol 13 2-7
Habid Zaidi 1999 Relevance of accurate Monte Carlo modeling in nuclear medical imaging Med. Phys. 26(4) 574-608
Habte F, Foudray A M K, Olcott P D, and Levin C S 2007 Effects of system geometry and other physical factors on photon sensitivity of high-resolution positron emission tomography phys. Med. Biol. 52 3753-3772
Herzog H 2006 Methods and application of positron-based medical imaging Radiation phys and chemistry 76(2) 337-342
Hossein Jadvar, Jacek K, Pinski and Peter S. Conti 2003 FDG PET in suspected recurrent and metastatic prostate cancer Oncology Reports 10 1485-1488
Iwata K, Greaves RG and Surko CM Gamma-ray spectra from positron annihilation on atoms and molecules 1997 Phys Rev A 55:3586–3604.
Jan S, Santin G, Strul D, Staelens S, Assie K and Autret D 2004 GATE: a simulation toolkit for PET and SPECT Phys. Med. Biol. 49 4543–61
Johnson E L , Jaszczak R J, Wang H, Li J, Greer K L, and Coleman R E 1995 IEEE Conference Record 4 1888-1892
Krenning E P, Kooij P P, Pauwels S, Breeman W A, Postema P T, De Herder W W, Valkema R and Kwekkeboom D J 1996 Somatostatin receptor: scintigraphy and radionuclide therapy Digestion 57 57–61
Lazaro D et al 2004 Validation of the GATE Monte Carlo simulation platform for modelling a CsI(Tl) scintillation camera dedicated to small-animal imaging Phys. Med. Biol. 49 271–85
Lutz Frank S, Hans-Juergen G, Birgit M, Eckart R, and Manfred B 2006 Performance comparison of two dual-head coincidence cameras of the first and latest generation Med Phys 33 329-360
Michael L, Sven-Erik S and Michael A. King 1999 Monte carlo calculations in nuclear Nuclear medicine Institute of Physics Publishing, Philadelphia, Penn
Sarlis, Nicholas J , Gourgiotis, Loukas, Guthrie, Lori C R N , B S N , Galen, Barbara C R N P , Skarulis, Monica C , Shawker, Thomas H , Patronas, Nicholas J , Reynolds and James C 2003 In-111 DTPA-Octreotide Scintigraphy for Disease Detection in Metastatic Thyroid Cancer: Comparison with F-18 FDG Positron Emission Tomography and Extensive Conventional Radiographic Imaging Clinical Nucl Med 28 208-217
Segall G. 2002 Assessment of myocardial viability by positron emission tomography Nucl. Med. Commun. 23 323-330
Simon R C, James A S and Michael E P 2003 Physics in Nuclear Medicine the third edition 239-241
Shibuya K, Yoshida E, Nishikido F, Suzuki T, Tsuda T and Inadama N 2007 Annihilation photon acollinearity in PET: volunteer and phantom FDG studies Phys Med Biol; 52 5249–5261
Soret M, Koulibaly P M, Darcourt J, Hapdey S and Buvat I 2003 Quantitative accuracy of dopaminergic neurotransmission imaging with 123I SPECT J. Nucl. Med. 44 1184–93
Staelen S, Strul D, Santin G, Vandenberghe S, Koole M, D’ AsselerY, Lemahieu I and Van de Walle R 2003 Monte Carlo simulations of a scintillation camera using GATE: validation and application modelling Phys. Med. Biol.48 3021–42
Virgolini I , Patri P , Novotny C , Traub T , Leimer M , Füger B , S. R. Li, Angelberger P, Raderer M , Wogritsch S , Kurtaran A , Kletter K and Dudczak R 2004 Comparative somatostatin receptor scintigraphy using In-111-DOTA-lanreotide and In-111-DOTA-Tyr3-octreotide versusF-18-FDG-PET for evaluation of somatostatin receptor-mediated radionuclide therapy 12 41-45
丁慧枝 2000 放射藥品學 偉明圖書