Radiobromine-labelled tracers for positron emission tomography: possibilities and pitfalls.
Radiobromine-labelled tracers for positron emission tomography: possibilities and pitfalls.
复制标题
用于正电子发射断层扫描的放射性溴标记示踪剂：可能性和陷阱。
DOI：
10.2174/1874471011104020076
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发表时间：
2011
影响因子：
2.3
通讯作者：
V. Tolmachev
中科院分区：
文献类型：
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作者：
V. Tolmachev
与单光子发射计算机断层扫描（SPECT）相比，使用正电子发射断层扫描（PET）进行放射性核素成像具有更好的灵敏度，更好的空间和时间分辨率以及更好的定量准确性。PET的一个限制是主要使用短寿命（半衰期为2小时）的放射性核素。通过使用寿命更长、“非常规”的正电子发射体，PET的应用可能会得到扩展。溴的两种正电子发射同位素75Br （T1/2 = 96.7 min）和76Br （T1/2 = 16.2 h）可以被认为是靶向蛋白质和肽以及小分子的标记，它们在常规生物正电子发射体提供的时间框架之外具有最佳成像时间。各种示踪剂可通过活化酚环的亲电溴化、亲电溴化和卤素交换进行标记。一个主要的问题是，在体内代谢的示踪剂可能导致形成放射性溴化物作为主要的放射性代谢物。放射性溴化物排泄非常缓慢，并分布在细胞外空间造成高背景。需要仔细的示踪剂设计优化，以避免将溴同位素引入PET实践中的这一障碍。
The use of positron emission tomography (PET) for radionuclide imaging provides better sensitivity, better spatial and temporal resolution and better quantification accuracy in comparison with single photon emission computed tomography (SPECT). One limitation of PET is the predominant use of short-lived (with half-life up to 2 h) radionuclides. Extension of PET utility might be achieved by the use of more long-lived, "non-conventional" positron emitters. Two positron-emitting isotopes of bromine, 75Br (T1/2 = 96.7 min) and 76Br (T1/2 = 16.2 h), can be considered as labels for targeting proteins and peptides, and for small molecules, which have an optimal imaging time outside the time frame provided by conventional biogenic positron emitters. Variety of tracers might be labelled by electrophilic bromination of activated phenolic rings, electrophilic bromodestannylation and halogen exchange. A major problem is that in vivo metabolism of tracers might lead to formation of radiobromide as a main radiocatabolite. Radiobromide is very slowly excreted, and is distributed in the extracellular space creating high background. Careful tracer design optimisation is required to avoid this obstacle in the introduction of bromine isotopes into PET practice.