配置雙偵測頭耦合造影(DHCI)系統的加馬造影機近幾年已漸廣為使用，此種儀器可報行傳統接醫的單光子造影與正子耦合造影，具多用途性、價格不貴等優點，但目前對此新式儀器的了解仍有限。為了解影響影像品質的因慌，須要探討其儀器造影特性。本文嘗試使用電腦程式來模擬DHCI系統，並對此電腦模擬實際臨床造影的可行性進行評估。
方法：藉由電腦程式\"SimSET"模擬實際DHCI系統的造影。利用空間解析度、線性度、圓柱假體與胸腔假體影像的模擬測試來獲得不同物理參數條件下的模擬結果。所選擇的模擬儀器參數儘可能與實際E. CAM+的DHCI系統相同以使模擬結果有實際意義。
結果：模擬空氣中點射源所得空間解析度方面在徑向解析度與量測值有段差距，但正切向解析度與文獻量測相近。在線性度測試中，呈現出投影角度取樣不足時會有假影存在。均勻活性圓柱假體的模擬由影像上可展現衰減效應，顯示此模擬可分析光子衰減的問題。模擬心臟造影的測試中，呈現薄心肌壁由於未經過衰減修正而造成的假性活性缺損。
結論：模擬結果目前仍不理想，但顯示具模擬實際臨床情況之潛力。未來若能針對缺失加以改善，便可使模擬結果更接近實際情形，進而以電腦模擬來分析影響DHCI系統造影的衰減與散射等效應。

Background: The gamma camera with dual-head coincidence imaging (DHCI) is widespread during last few years. This instrument for single and positron coincidence imaging is a multipurpose system with reduced cost. We have limited knowledge on this innovative device, so we need to explore its imaging characteristics to know the factors that affect image quality. In this study, we try to use computer simulation of DHCI system, and to evaluate the practicality for actual imaging and clinical situation.
Methods: We used computer program "SimSET" to simulate the DHCI imaging. The simulation tests-spatial resolution, linearity, cylindrical phantom and torso phantom images were performed to obtain simulation results based on variable physical parameters. Simulation parameters were chosen based on real DHCI system-E. CAM+, thus makes the simulation results meaningful.
Results: The spatial resolution is obtained by simulating the point source in air, the radial resolution behaves differential form measured one, but tangential resolution matches the measurement results form the reference. In linearity test, it shows that there exist artifacts when the sampling projection angles are not enough. The simulation of uniform activity in a cylindrical phantom shows photon attenuation effect in the image, which demonstrates that photon attenuation can be analyzed by simulation. The simulated cardiac images reveals that fake activity loss results from non-attenuation correction in the thin myocardium walls.
Conclusion: Even though the simulation results are not identical to phantom studies yet, they have potential for setting actual clinical imaging situations. If we can further improve the drawbacks, then we could make the simulated results match the real experimental results. Then we could analyze some effects such as attenuation and scatter that affect DHCI system's image quality.