Ambrosini V, Morigi J J, Nanni C, Castellucci P, Fanti S
Nuclear Medicine DIMES, University of Bologna and S Orsola‑Malpighi Hospital, Bologna, Italy -
Q J Nucl Med Mol Imaging. 2015 Mar;59(1):58-69. Epub 2015 Feb 12.
Neuroendocrine neoplasms (NEN) functional imaging is an evolving field that witnessed major advances in the past two decades. The routine use of PET/CT with an array of new radiotracers to specifically study NEN resulted in an increase in lesions detection. Currently, PET radiopharmaceuticals for NEN imaging include both metabolic ([18F]DOPA, [18F]FDG, [11C]/[18F]-HTP) and receptor-mediated compounds ([68Ga]DOTA-peptides). Discussion is still on-going regarding the clinical setting that may benefit the most from the use of one tracer over the other. [68Ga]DOTA-peptides are accurate for the detection of well differentiated NEN and are increasingly employed. Moreover, providing data on somatostatin receptors expression on NEN cells, they represent a fundamental procedure to be performed before starting therapy, as well as to guide treatment, with either hot or cold somatostatin analogues. The easy and economic synthesis process also favours their clinical employment even in centres without an on-site cyclotron. [18F]DOPA is accurate for studying well differentiated tumours however the difficult and expensive synthesis have limited its clinical employment. It currently can be successfully used for imaging tumours with variable to low expression of SSR (medullary thyroid carcinoma, neuroblastoma, pheocromocytoma), that cannot be accurately studied with [68Ga]DOTA-peptides. [11C]/[18F]-HTP has also been proposed to image well differentiated NEN, on the basis of serotonin pathway activity, for which [11C]/[18F]-HTP can be used as precursor. However, although preliminary data are encouraging, the feasibility of its widespread clinical use is still under discussion, mainly limited by a complex synthesis process and more proven advantages over other currently employed compounds. This review aims to provide an overview of the current status and clinical application of PET tracers to image well differentiated NEN and to focus on the still open-issues of debate.
神经内分泌肿瘤（NEN）的功能成像领域不断发展，在过去二十年中取得了重大进展。PET/CT与一系列新型放射性示踪剂的常规使用，专门用于研究NEN，导致病变检测率增加。目前，用于NEN成像的PET放射性药物包括代谢类（[18F]多巴、[18F]氟代脱氧葡萄糖、[11C]/[18F]-羟色氨酸）和受体介导的化合物（[68Ga]多柔比星肽）。关于哪种示踪剂在何种临床情况下使用能带来最大益处的讨论仍在进行中。[68Ga]多柔比星肽对高分化NEN的检测准确，且应用越来越广泛。此外，它能提供NEN细胞上生长抑素受体表达的数据，是开始治疗前以及使用热或冷生长抑素类似物指导治疗时要进行的基本检查。其简单且经济的合成过程也有利于其在没有现场回旋加速器的中心临床应用。[18F]多巴对研究高分化肿瘤准确，但合成困难且昂贵，限制了其临床应用。目前它可成功用于成像SSR表达可变至低的肿瘤（甲状腺髓样癌、神经母细胞瘤、嗜铬细胞瘤），而这些肿瘤用[68Ga]多柔比星肽无法准确研究。基于血清素途径活性，[11C]/[18F]-羟色氨酸也被提议用于高分化NEN的成像，[11C]/[18F]-羟色氨酸可作为其前体。然而，尽管初步数据令人鼓舞，但其广泛临床应用的可行性仍在讨论中，主要受合成过程复杂以及相对于其他现有化合物优势不明显的限制。本综述旨在概述PET示踪剂用于高分化NEN成像的现状和临床应用，并关注仍存在争议的问题。
