胞质内黑色素色素是清明细胞肉瘤（CCS）的特征，该疾病是一种特别致命的软组织肉瘤。[18F]-N-(2-(二乙胺)乙基)-5-(2-(2-(2-氟乙氧基)乙氧基)乙氧基)吡哆酰胺（[18F]-PFPN）是一种具有高亲和力的正电子发射断层（PET）显像探针。因此，本研究旨在探讨CCS患者中黑色素靶向[18F]-PFPN PET的可行性。这项前瞻性单中心研究招募了经病理证实的CCS患者。[18F]-FDG PET /计算机断层扫描和[18F]-PFPN PET /磁共振成像扫描相互间隔不超过1周进行。记录了病变数量和[18F]-FDG和[18F]-PFPN PET参数（最大标准摄取值[SUVmax]、平均标准摄取值[SUVmean]、代谢/黑色素肿瘤体积[MTV/MLTV]和总病变醛糖化作用/黑色素[TLG/TLM]）。三例CCS患者接受了PET显像。[18F]-PFPN PET检测到了56个病变，包括原发肿瘤和远处转移。 [18F]-PFPN PET和[18F]-FDG PET未检测到相同的病变。 [18F]-FDG成像中的12个病变（12/39, 30.77％）在[18F]-PFPN成像中被遗漏，[18F]-PFPN成像中的20个病变（20/47, 42.55%）在[18F]-FDG成像中被遗漏。定量分析显示，所有病变中[18F]-FDG SUVmean（4.60 ± 3.24）高于[18F]-PFPN SUVmean（3.0 ± 2.63）（P = 0.01）。[18F]-PFPN和[18F]-FDG的SUVmax、SUVmean、MLTV/MTV和TLM/TLG值之间没有显著相关性（P > 0.05）。黑色素靶向[18F]-PFPN PET成像对CCS的诊断是可行的。[18F]-PFPN和[18F]-FDG PET成像显示了不同的影像学特征，证明了这两种示踪剂的互补作用。在CCS患者中，优先选择两种成像模式的联合使用。 NCT05963035.©2023年。作者，独家授权给Springer-Verlag GmbH Germany，Springer Nature的一部分。

Intracytoplasmic melanin pigment is a characteristic of clear cell sarcoma (CCS), which is a particularly deadly type of soft-tissue sarcoma. [18F]-N-(2-(diethylamino)ethyl)-5-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy)picolinamide ([18F]-PFPN) is a positron emission tomography (PET) probe characterized by high melanin affinity. Therefore, this study aimed to investigate the feasibility of melanin-targeted [18F]-PFPN PET in patients with CCS.This prospective single-centre study recruited patients with pathologically confirmed CCS. [18F]-FDG PET/computed tomography and [18F]-PFPN PET/magnetic resonance imaging scans were performed within 1 week of each other. The lesion numbers and [18F]-FDG and [18F]-PFPN PET parameters (maximum standardized uptake value [SUVmax], mean standardized uptake value [SUVmean], metabolic/melanotic tumour volume [MTV/MLTV], and total lesion glycolysis/melanin [TLG/TLM]) were collected.Three patients with CCS were recruited and received PET imaging. A total of 56 lesions were detected on [18F]-PFPN PET, including primary tumour and distant metastases. Identical lesions were not detected on [18F]-PFPN and [18F]-FDG PET. Twelve lesions (12/39, 30.77%) on [18F]-FDG imaging were missed on [18F]-PFPN, and 20 lesions (20/47, 42.55%) on [18F]-PFPN imaging were missed on [18F]-FDG. In quantitative analysis, the [18F]-FDG SUVmean (4.60 ± 3.24) was higher than the [18F]-PFPN SUVmean (3.0 ± 2.63) in all lesions (P = 0.01). No significant correlations were found between the SUVmax, SUVmean, MLTV/MTV, and TLM/TLG values of [18F]-PFPN and [18F]-FDG (P > 0.05).Melanin-targeted [18F]-PFPN PET imaging is feasible for the diagnosis of CCS. Different imaging features were displayed on [18F]-PFPN and [18F]-FDG PET imaging, demonstrating the complementary role of the tracers. Combined use of the two imaging modalities would be preferred in patients with CCS.NCT05963035.© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.