Fundamental and Clinical Study on Dynamic Single Photon Emission CT

动态单光子发射CT(SPECT)使用SPECT系统和重复旋转的对置伽马相机进行。对三维功能成像的发展和临床应用进行了基础和临床研究。1.基础研究。对数据采集和吸收校正方法的分辨率、灵敏度和一致性进行了评价。通过仿真研究，估计了数据采集过程中放射性变化对图像质量的影响。改变率为10%时为1.5%，改变率为30%时为2.8%，改变率为50%时为3.3%，说明伪影的影响不是图像质量的主要问题。2.临床研究。(1)脑血流三维功能成像：采用Kanno和Lassen提出的方法对每30s采集一次的SPECT数据进行分析，生成脑血流断层图像。结果表明，这个m…对于X线、CT未见的轻度脑血管疾病的诊断和手术疗效的评价，方法更有价值。(2)门控血池研究：以~(99m)Tc-RBC为示踪剂，采集门控血池SPECT数据。对重建图像进行旋转、右室数据去除、断层数据求和和傅立叶分析，得到与左心室长轴平行或垂直的相位和幅度图像。在缺血性心脏病的诊断中，这种方法在评估下壁和后壁的室壁运动异常方面特别有用。(3)~(99)m-PMT肝胆功能显像：以心脏的时间-活动曲线(TAC)为输入，以肝脏图像各元素的时间-活动曲线(TAC)为输出函数，对1min序列的SPECT数据进行数学去卷积分析，得到有效血流量和通过时间的函数图像。尽管正常人和肝硬化组的总血流量、局部血流量和平均通过时间(MTT值)均呈显著负相关，但仍有部分患者局部血流量正常，MTT值与总血流量下降相反。(4)~(99m)Tc-DTPA肾功能显像：采用相同的去卷积分析方法，拍摄GFR和MTT型肾功能图像。这些图像有助于鉴别MTT值延长、GFR降低的局灶性病变与MTT值延长、GFR正常者。较少

Dynamic single photon emission CT (SPECT) was performed using a SPECT system with repeatedly rotaing opposed gamma cameras. Fundamental and clinical studies were made on the development and clinical application of three dimensional functional imaging. 1. Fundamental study. Methods for data aquisition and absorption correction were evaluated in relation to resolution, sensitivity and uniformity. The effect of the artifact on the image quality, which is produced by the alteration of radioactivity during data collection, were estimated by a simulation study. The results of 1.5% with the alteration rate of 10%, 2.8% with the rate of 30%, 3.3% with the rate of 50% indicated that the effect of the artifact was not a major problem for image quality. 2. Clinical study. (1) Three dimensional cerebral blood flow functional imaging: SPECT data collected every 30 sec were analized by the method proposed by Kanno and Lassen to make tomographic images of cerebral blood flow. It was shown that this m … More ethod was usefull in the diagnosis of such mild cerebrovascular diseasesas not seen on X-ray CT and in the evaluation of the effect of surgical therapy. (2) Gated blood pool study: Gated blood pool SPECT data were aquired using Tc-99m-RBC as a tracer. Reconstructed images were processed by rotation of the images, removal of the data over right ventricle, summation of the tomographic data and Fourier analysis to obtain phase and amplitude images which are either paralled or perpendicular to long axis of left ventricle. In the diagnosis of ischemic heart disease, this method was particularly useful in the evaluation of wall motion abnormalities in inferior and posterior walls. (3) Tc-99m-PMT hepatobiliary functional imaging: One min serial SPECT data were analized by the mathematical deconvolution using time-activity curve (TAC) over the heart as input and TAC over each element of liver images as output function to construct functional images of effective blood flow and transit times. Although there were significant negative correlations between each of total and regional blood flow and mean transit time (MTT) in normals and cases with liver cirrhosis,there were some cases with normal regional blood flow and MTT against decreased total blood flow. (4) Tc-99m-DTPA renal functional imaging: Using the same method of deconvolution analysis, functional images of GFR and MTT were made. These images were useful in differentiating, pathophysiology of focal diseases with prolonged MTT and decreased GFR from those with prolonged MTT and normal GFR. Less