本文關(guān)鍵詞： 雙平板 PET γ相機(jī) 歸一化校正 幾何校正　出處：《東華理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：正電子發(fā)射斷層成像(Position Emission Tomography,PET)與單光子發(fā)射計(jì)算機(jī)斷層成像(Single Photon Emission Computed Tomography)作為兩種目前應(yīng)用最為廣泛的核醫(yī)學(xué)成像技術(shù),通過將放射性藥物注入人體內(nèi),在獲取生命體的部分器官的代謝中有著強(qiáng)大的優(yōu)勢,可以為一系列重大疾病的早期診斷及療效評估提供信息。雙平板多功能核醫(yī)學(xué)成像設(shè)備作為兼具兩種成像模式,采用平板探測器結(jié)構(gòu),真正實(shí)現(xiàn)“一機(jī)多用”,具有探測條件靈活,適用場景多樣,靈敏度高等優(yōu)勢,有益于臨床應(yīng)用和推廣。本論文完成雙平板多功能核醫(yī)學(xué)成像系統(tǒng)開展的主要研究工作如下:針對影響圖像質(zhì)量的多種因素進(jìn)行深入研究與探討,包括系統(tǒng)探測效率不均勻,以及γ相機(jī)成像工作模式下的幾何偏移與探測器響應(yīng)不一致等。對影響圖像質(zhì)量的物理因素和數(shù)據(jù)的統(tǒng)計(jì)特性進(jìn)行深入研究。PET工作模式下,探測器系統(tǒng)響應(yīng)一致性主要受到幾何效率、本征效率和光子穿過晶體條的有效距離等因素的影響,通過對這些因素的分析,提出了一種基于變量分離技術(shù)的歸一化校正算法。該方法將幾何因素與其他因素剝離,與后續(xù)圖像重建環(huán)節(jié)實(shí)現(xiàn)無縫銜接,有效地緩解了探測效率不均勻?qū)D像質(zhì)量的影響,且具有實(shí)驗(yàn)方案簡潔易行等特點(diǎn)。γ相機(jī)工作模式下,細(xì)致分析了幾何偏移對成像效果的影響,根據(jù)應(yīng)用場景需求,設(shè)計(jì)了一套幾何參數(shù)校正算法,該方法通過一系列幾何參數(shù)建立了投影空間和物體空間的準(zhǔn)確映射關(guān)系,采用幾何參數(shù)對探測器在軸向發(fā)生的旋轉(zhuǎn)、偏移和傾斜等幾何誤差和投影數(shù)據(jù)的坐標(biāo)關(guān)系進(jìn)行建模,提出了點(diǎn)源移動(dòng)檢測技術(shù)方案,通過提取以上幾何參數(shù)的誤差值,優(yōu)化圖像質(zhì)量。本論文完成雙平板多功能核醫(yī)學(xué)系統(tǒng)在兩種工作模式下的校正算法的設(shè)計(jì)與開發(fā),基于GATE模擬對系統(tǒng)進(jìn)行評價(jià)與測試,并將校正算法應(yīng)用于設(shè)備中。
[Abstract]:Positron emission tomography (PET) and single Photon Emission Computed tomography (SPECT) are two of the most widely used nuclear medical imaging techniques, by injecting radioactive drugs into human body. It can provide information for the early diagnosis and evaluation of a series of major diseases. The dual-plate multifunctional nuclear medical imaging device has two imaging modes, and has a strong advantage in obtaining the metabolism of some organs of the living body, and it can provide information for the early diagnosis and evaluation of the curative effect of a series of major diseases. With the flat panel detector structure, the "one machine multipurpose" is realized, which has the advantages of flexible detection conditions, various applicable scenes, high sensitivity, and so on. This paper is beneficial to clinical application and popularization. The main research work of this paper is as follows: the factors that affect the image quality, including the uneven detection efficiency of the system, are studied and discussed in detail. And the geometric migration in 緯 camera imaging mode is not consistent with the detector response. The physical factors affecting the image quality and the statistical characteristics of the data are studied in detail under the working mode of PET. The response consistency of the detector system is mainly affected by geometric efficiency, intrinsic efficiency and effective distance of photons passing through the crystal strip. In this paper, a normalized correction algorithm based on variable separation technique is proposed, in which geometric factors are separated from other factors and connected seamlessly with subsequent image reconstruction, which effectively alleviates the effect of uneven detection efficiency on image quality. The effect of geometric migration on imaging effect is analyzed in detail, and a set of geometric parameter correction algorithm is designed according to the requirements of the application scene. Based on a series of geometric parameters, the accurate mapping relationship between projection space and object space is established, and the geometric errors such as rotation, offset and tilt of the detector in the axial direction and the coordinate relation of the projection data are modeled by geometric parameters. A point source moving detection scheme is proposed to optimize the image quality by extracting the error values of the above geometric parameters. In this paper, the design and development of the correction algorithm for the dual-plate multifunctional nuclear medicine system in two working modes are completed. The system is evaluated and tested based on GATE simulation, and the calibration algorithm is applied to the equipment.
【學(xué)位授予單位】：東華理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：R817;TP391.41

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本文編號(hào)：1501224