The diagnostic work-up of patients with fever of unknown origin (FUO) begins with a thorough history and physical examination, complete blood count with differential, chest x-ray, urinalysis and culture, electrolyte panel, liver enzymes, erythrocyte sedimentation rate, and C-reactive protein level. Additional imaging procedures, including nuclear medicine tests, are generally used as second-line procedures, with ¹⁸F-FDG PET and PET/CT assuming increasingly important roles in the diagnostic work-up. The Society of Nuclear Medicine and Molecular Imaging, the Infectious Diseases Society of America, and the American College of Nuclear Medicine convened an autonomous expert work group to comprehensively review the published literature for nuclear imaging in adults and children with FUO and establish appropriate use criteria (AUC). This process was performed in accordance with the Protecting Access to Medicare Act of 2014, which requires that all referring physicians consult AUC by using a clinical decision support mechanism before ordering advanced diagnostic imaging services. The complete findings and discussions of the work group were published on January 8, 2023, and are available at https://www.snmmi.org/ClinicalPractice/content.aspx?ItemNumber=15666. The AUC in the final document are intended to assist referring health care providers in appropriate use of nuclear medicine imaging procedures in patients with FUO. The work group noted limitations in the current literature on nuclear medicine imaging for FUO, with the need for well-designed prospective multicenter investigations. Consensus findings from published data and expert opinions were used to create recommendations in common clinical scenarios for adults and children. Included in the complete document is a discussion of inflammation of unknown origin (IUO), a recently described entity. In view of the fact that the criteria for FUO and IUO are similar (except for fever > 38.3°C [100.9°F]) and that the most common etiologies of these 2 entities are similar, it is the expert opinion of the work group that the recommendations for nuclear medicine imaging of FUO are also applicable to IUO. These recommendations are included in the full guidance document. This summary reviews rationale, methodology, and main findings and refers the reader to the complete AUC document.

不明原因发热 （FUO） 患者的诊断性病情检查首先要全面询问病史和体格检查、全血细胞计数和分类计数、胸部 X 线检查、尿液分析和培养、电解质检查、肝酶、红细胞沉降率和 C 反应蛋白水平。其他影像学检查，包括核医学检查，通常用作二线检查，^{其中 18}F-FDG PET 和 PET/CT 在诊断检查中发挥着越来越重要的作用。核医学和分子影像学会、美国传染病学会和美国核医学会召集了一个自主专家工作组，以全面审查已发表的用于成人和儿童 FUO 细胞核成像的文献，并建立适当的使用标准 （AUC）。此过程是根据 2014 年《保护医疗保险法案》执行的，该法案要求所有转诊医生在订购高级诊断成像服务之前使用临床决策支持机制咨询 AUC。工作组的完整调查结果和讨论已于 2023 年 1 月 8 日发布，可在 https://www.snmmi.org/ClinicalPractice/content.aspx?ItemNumber=15666 上查阅。最终文件中的 AUC 旨在帮助转诊医疗保健提供者在 FUO 患者中正确使用核医学成像程序。工作组注意到当前关于 FUO 核医学成像的文献存在局限性，需要精心设计的前瞻性多中心调查。来自已发表数据和专家意见的共识结果用于为成人和儿童的常见临床场景提供建议。 完整文件中包括对不明原因炎症 （IUO） 的讨论，这是最近描述的一种实体。鉴于 FUO 和 IUO 的标准相似（发热 > 38.3°C [100.9°F] 除外），并且这 2 个疾病最常见的病因相似，工作组的专家意见认为，FUO 核医学成像的建议也适用于 IUO。这些建议包含在完整的指导文件中。本摘要回顾了基本原理、方法和主要发现，并向读者推荐了完整的 AUC 文档。