Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via L. Borsari, 46-44121 Ferrara, Italy.
Department of Translational Medicine, University of Ferrara, Via Fossato di Mortara, 70 c/o Viale Eliporto, 46-44121 Ferrara, Italy.
Molecules. 2022 Feb 10;27(4):1188. doi: 10.3390/molecules27041188.
The favorable nuclear properties in combination with the rich coordination chemistry make technetium-99m the radioisotope of choice for the development of myocardial perfusion tracers. In the early 1980s, [Tc]Tc-Sestamibi, [Tc]Tc-Tetrofosmin, and [Tc]Tc-Teboroxime were approved as commercial radiopharmaceuticals for myocardial perfusion imaging in nuclear cardiology. Despite its peculiar properties, the clinical use of [Tc]Tc-Teboroxime was quickly abandoned due to its rapid myocardial washout. Despite their widespread clinical applications, both [Tc]Tc-Sestamibi and [Tc]Tc-Tetrofosmin do not meet the requirements of an ideal perfusion imaging agent due to their relatively low first-pass extraction fraction and high liver absorption. An ideal radiotracer for myocardial perfusion imaging should have a high myocardial uptake; a high and stable target-to-background ratio with low uptake in the lungs, liver, stomach during the image acquisition period; a high first-pass myocardial extraction fraction and very rapid blood clearance; and a linear relationship between radiotracer myocardial uptake and coronary blood flow. Although it is difficult to reconcile all these properties in a single tracer, scientific research in the field has always channeled its efforts in the development of molecules that are able to meet the characteristics of ideality as much as possible. This short review summarizes the developments in Tc myocardial perfusion tracers, which are able to fulfill hitherto unmet medical needs and serve a large population of patients with heart disease, and underlines their strengths and weaknesses, the lost and found opportunities thanks to the developments of the new ultrafast SPECT technologies.
锝-99m 的有利核特性加上丰富的配位化学特性，使其成为开发心肌灌注示踪剂的首选放射性同位素。在 20 世纪 80 年代早期，[Tc]Tc-Sestamibi、[Tc]Tc-Tetrofosmin 和 [Tc]Tc-Teboroxime 被批准为核心脏病学中用于心肌灌注成像的商业放射性药物。尽管具有特殊性质，但由于其快速的心肌洗脱，[Tc]Tc-Teboroxime 的临床应用很快被放弃。尽管 [Tc]Tc-Sestamibi 和 [Tc]Tc-Tetrofosmin 得到了广泛的临床应用，但由于其首次通过提取分数相对较低和肝脏吸收较高，它们都不符合理想灌注成像剂的要求。用于心肌灌注成像的理想放射性示踪剂应具有高心肌摄取量；在图像采集期间，肺部、肝脏和胃中的摄取量低，具有高且稳定的靶与背景比；具有高的首次通过心肌提取分数和非常快速的血液清除率；以及放射性示踪剂心肌摄取量与冠状动脉血流量之间存在线性关系。尽管在单个示踪剂中很难调和所有这些特性，但该领域的科学研究一直致力于开发尽可能符合理想特性的分子。这篇简短的综述总结了 Tc 心肌灌注示踪剂的发展，这些示踪剂能够满足迄今为止未满足的医疗需求，并为大量心脏病患者服务，并强调了它们的优缺点，以及由于新的超快 SPECT 技术的发展而失去和发现的机会。
