Kinetics of positron emitters in vivo characterized with a beta probe.
Kinetics of positron emitters in vivo characterized with a beta probe.
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用 β 探针表征的体内正电子发射器动力学。
DOI：
10.1152/ajpheart.1982.242.1.h62
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
Ter-Pogossian,MM
中科院分区：
文献类型：
--
作者：
Lerch,RA;Ambos,HD;Bergmann,SR;Sobel,BE;Ter-Pogossian,MM
为了便于表征局部心肌动力学的正电子发射示踪剂在体内没有失真的活动以外的地区的利益，探针的开发和评价监测放射性通过检测正电子本身。这些粒子（β粒子）在组织中的最大射程仅为几毫米，而不是由于正电子湮没而发射的更大范围的伽马光子。在开胸犬冠状动脉内注射0.5-1.5 mCi [15 O]H2O（一种用于测量心肌血流量的示踪剂）或6.0-8.0 mCi [11 C]棕榈酸盐（一种用于无创评估心肌代谢的示踪剂）后，测定局部心肌时间-活动曲线。[11 C]棕榈酸注射后的时间-活性曲线清楚地描绘了先前在离体灌注心脏中体外确定的心肌示踪剂清除的特定组分。[15 O]H2O的心肌冲洗是单指数的，持续时间超过2分钟，而心室血中再循环示踪剂不会引起心肌冲洗的扭曲。根据两种示踪剂的重复测定，单指数清除期间测得的示踪剂清除率的重现性较高。开发的β探测器探针克服了γ探测系统或连续心肌活检的计数良好的固有局限性，用于体内正电子发射示踪剂的研究，并应有助于评估体内正电子发射断层扫描相关的示踪剂动力学的影响因素。
To facilitate characterization of regional myocardial kinetics of positron-emitting tracers in vivo without distortion by activity outside the region of interest, a probe was developed and evaluated for monitoring radioactivity by detection of positrons themselves. These particles (beta particles) have a maximal range in tissue of only few millimeters rather than the larger range of gamma photons emitted as a result of positron annihiliation. Regional myocardial time-activity curves were determined in open-chest dogs after intracoronary injection of 0.5-1.5 mCi [15O]H2O, a tracer used for measurement of myocardial blood flow, or 6.0-8.0 mCi [11C]palmitate, a tracer used for noninvasive assessment of myocardial metabolism. Time-activity curves after [11C]palmitate injection clearly delineated specific components of myocardial tracer clearance previously identified in vitro in isolated perfused hearts. Myocardial washout of [15O]H2O was monoexponential for more than 2 min without distortion induced by recirculating tracer in ventricular blood. Reproducibility of measured tracer clearance rates during monoexponential clearance was high based on duplicate determinations for both tracers. The beta-detector probe developed overcomes several intrinsic limitations of gamma-probe systems or well counting of serial myocardial biopsies for studies of positron-emitting tracers in vivo and should facilitate assessment of factors of influencing tracer kinetics in vivo relevant to positron-emission tomography.