【摘要】：正電子發(fā)射斷層成像（Positron Emission Tomography，簡稱PET）是一種非侵入式的造影方法，它通過探測活體內攝入放射性示蹤劑的分布，無創(chuàng)、定動態(tài)地評估生物體內各種器官的代謝水平、生化反應、功能活動和灌注。作為當今核醫(yī)學診斷和研究的尖端技術，PET在腫瘤、心血管、神經系統等的早期診斷、療效評估以及基礎研究等領域有著獨特的應用價值。數字化的PET數據獲得系統能夠有效解決傳統PET系統容易受環(huán)境干擾，校正困難的問題，同時引入數字信號處理技術帶來的多種優(yōu)勢，是目前PET儀器設計的熱點方向。 本文對一種新的全數字化脈沖獲取能量獲取方法——多電壓閾值采樣法(簡稱MVT)獲取能量的關鍵因素進行了研究，包括噪聲，基線，時間數字轉換器（簡稱TDC）精度，以及閾值設置。提出了基于MVT的下降沿噪聲處理方法，準確的獲取脈沖的能量信息。并模擬仿真了實際硬件閾值個數與時間數字轉換器的精度對MVT能量獲取的影響。實現了基于MVT的基線校正算法。為實現MVT方法的PET采集系統奠定了基礎。 在仿真的基礎上，本文實現了一個基于MVT方法的閃爍能量脈沖獲取系統，，該系統具有死時間短，全數字化，易于后期校正等優(yōu)勢。并以該系統為基礎，對之前的仿真方法進行了驗證，取得了初步的結果，為PET系統的全數字化能量獲取打下了基礎。 最后，本文以華中科技大學研制的數字化小動物PET系統為基礎，充分運用閃爍脈沖特性和數字信號處理技術，研究并實現了閃爍脈沖的能量信息獲取單元。在結合實際性能因素的考慮下，利用數字積分方法，獲得了良好的能量性能，達到了預期的要求。
[Abstract]:Positron Emission Tomography (Positron Emission Tomography,) is a non-invasive imaging method that dynamically evaluates the metabolic level and biochemical reactions of various organs in living organisms by detecting the distribution of radioactive tracers in vivo. Functional activity and perfusion. As a cutting-edge technology in nuclear medicine diagnosis and research, PET has unique application value in early diagnosis, evaluation of curative effect and basic research in tumor, cardiovascular, nervous system and so on. The digital PET data acquisition system can effectively solve the problem that traditional PET system is vulnerable to environmental interference and difficult to correct. At the same time, the introduction of digital signal processing technology brings a variety of advantages, which is a hot spot in the design of PET instruments. In this paper, a new all-digital pulse acquisition method, multi-voltage threshold sampling (MVT), is studied, which includes the accuracy of noise, baseline and time-digital converter (TDC). And threshold setting. A method of noise processing based on MVT is proposed to obtain the energy information of pulse accurately. The effect of the actual hardware threshold number and the precision of the time digital converter on the MVT energy acquisition is simulated and simulated. The baseline correction algorithm based on MVT is implemented. It lays a foundation for the realization of PET acquisition system of MVT method. On the basis of simulation, a flash energy pulse acquisition system based on MVT method is implemented in this paper. The system has the advantages of short dead time, full digitization and easy post-correction. Based on this system, the previous simulation method is verified, and the preliminary results are obtained, which lays the foundation for the full digital energy acquisition of PET system. Finally, based on the digital small animal PET system developed by Huazhong University of Science and Technology, the energy information acquisition unit of scintillation pulse is studied and realized by making full use of the characteristics of scintillation pulse and digital signal processing technology. Under the consideration of the actual performance factors, the digital integral method is used to obtain good energy performance and meet the expected requirements.
【學位授予單位】：華中科技大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：R310

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