SPET和PET在探测冠心病心肌缺血与心肌存活的应用价值  

Application of SPET & PET in Detecting Myocardial Ischemia and Myocardial Viability in Coronary Artery Disease

作　　者：刘秀杰[1] 张晓丽[1] 

机构地区：[1]中国医科院中国协和医科大学阜外心血管病医院

出　　处：《引进国外医药技术与设备》1998年第1期41-41,共1页

摘　　要：单光子发射型断层显像仪[single-photon emission(computed)tomograph,SPET,SPECT]和正电子放射型断层显像仪(positron emission tomo-graph,PET)是当前核医学临床检查的高级精密设备,它们与超声、X线CT、磁共振成像(MRI)共同构成四大影像技术。SPET显像的主要原理是测量发射单光子(如γ射线)的核素标记化合物在人体内的分布,如^(99m)锝(^(99m)Tc)及其标记化合物。PET显像的主要原理是测量发射正电子的核素(^(18)F,^(11)C,^(13)N,^(15)O)在体内的分布,正电子在衰变过程中,产生湮没辐射,同时发射两个能量为511KeV方向相反(180°)的γ光子,采用符合线路探测器(coincidence detector),即PET可以准确探测。 SPET用于冠心病的诊断,主要包括:核素心肌灌注断层显像和核素心室造影,后者可以了解心室功能和局部室壁运动。目前国际上应用较多的心肌灌注显像剂有^(201)Tl、^(99m)Tc-甲氧异腈(^(99m)Tc-MIBI)、^(99m)Tc-替曲膦(^(99m)Tc-tetrofosmin)以及^(99m)Tc-替肟锝(^(99m)Tc-teborox-ime)。其中^(201)Tl应用时间最长,优点是注射一次即可获得运动(exercise)和再分布(redistribution)的图像,但半衰期偏长(73h),能量偏低;而^(99m)Tc-MIBI显像的优点是半衰期短(6h)、对病人的辐射剂量低,可投给较大剂量以改善图像?Single photon emission (computed) tomograph(SPET SPECT) and positron emission tomograph (PET)are highly advanced equipments of nuclear medicine whichprovide in vivid three - dimensional(3 - D) images the dis-tribution of radiotracers within the body. SPET and PET withUFCT, MRI, Echocardiology are the major imaging tech-niques in diagnosis and management of coronary artery dis-ease (CAD). SPET and PET provide clinical physicianswith physiological and biochemical information. The radio-tracers used in SPET studies are radionuclides which emitsingle photon (γray )such as ^(201)Tl, ^(99m)Tc. PET is based onthe utilization of artificially produced positron emitting ra-dionuclides such as ^(18)F, ^(11)C, ^(13)N, ^(15)O, ect. SPET used in de-tection of coronary artery disease, includes two techniques:myocardial perfusion imaging and radionuclide ventricu-lography, which are used in assessing ventricular functionand perfusion.In myocardial perfusion imaging, ^(201)Tl and ^(99m)Tc - MIBI arethe most widely used radionuclides and compounds. Butmyocardial perfusion imaging with ^(201)Tl has several physicalfeatures that make it not optimally suitable for myocardialimaging So, there is growing interest in the development of^(99m)Tc labeled agents to supplant ^(201)Tl. Among them,^(99m)Tc - MIBI and ^(99m)Tc - tetrofosmin which provide highquality images are very promising.For accurate detection of myocardial ischemia, stress test(including exercise and pharmacological test) is absolutelynecessary. The pharmacological agents such as dipyri-damole, adenosine, which can dilate the normal coronaryartery and increase coronary blood flow, however, can notdilate the stenotic coronary artery and then regional my-ocardial hypoperfusion can be observed.Two kinds of myocardial perfusion imaging techniques havebeen used: gated and non - gated myocardial tomography.Gated SPET allows simultaneous assessment of myocardialperfusion and both global and regional function. Increasingthe dosage and prolonging the acquisition time of SPET canim

关 键 词：冠心病 心肌缺血 心肌存活 SPECT PET 

分 类 号：R541.404[医药卫生—心血管疾病]