Dedicated breast positron emission tomography (dbPET) is an emerging technology with high sensitivity and spatial resolution that enables detection of sub-centimeter lesions and depiction of intratumoral heterogeneity. In this study, we report our initial experience with dbPET using [F-18]fluoroestradiol (FES) in assessing ER+ primary breast cancers. Six patients with >90% ER+ and HER2− breast cancers were imaged with dbPET and breast MRI. Two patients had ILC, three had IDC, and one had an unknown primary tumor. One ILC patient was treated with letrozole, and another patient with IDC was treated with neoadjuvant chemotherapy without endocrine treatment. In this small cohort, we observed FES uptake in ER+ primary breast tumors with specificity to ER demonstrated in a case with tamoxifen blockade. FES uptake in ILC had a diffused pattern compared to the distinct circumscribed pattern in IDC. In evaluating treatment response, the reduction of SUV_max was observed with residual disease in an ILC patient treated with letrozole, and an IDC patient treated with chemotherapy. Future study is critical to understand the change in FES SUV_max after endocrine therapy and to consider other tracer uptake metrics with SUV_max to describe ER-rich breast cancer. Limitations include variations of FES uptake in different ER+ breast cancer diseases and exclusion of posterior tissues and axillary regions. However, FES-dbPET has a high potential for clinical utility, especially in measuring response to neoadjuvant endocrine treatment. Further development to improve the field of view and studies with a larger cohort of ER+ breast cancer patients are warranted.

专用乳腺正电子发射断层扫描（dbPET）是一种具有高灵敏度和空间分辨率的新兴技术，能够检测亚厘米病变并描绘肿瘤内异质性。在这项研究中，我们报告了使用 [F-18] 氟雌二醇 (FES) 进行 dbPET 评估 ER+ 原发性乳腺癌的初步经验。6 名 ER+ 和 HER2− 乳腺癌患者的比例大于 90%，使用 dbPET 和乳腺 MRI 进行成像。两名患者患有 ILC，三名患者患有 IDC，一名患者原发肿瘤未知。一名 ILC 患者接受来曲唑治疗，另一名 IDC 患者接受新辅助化疗，无需内分泌治疗。在这个小队列中，我们观察到 ER+ 原发性乳腺肿瘤中 FES 的摄取，并在他莫昔芬阻断的病例中证实了对 ER 的特异性。与 IDC 中明显的限制模式相比，ILC 中的 FES 摄取具有扩散模式。在评估治疗反应时，在接受来曲唑治疗的 ILC 患者和接受化疗治疗的 IDC 患者中观察到SUV _{max降低，并伴有残留病灶。未来的研究对于了解内分泌治疗后 FES SUV max}的变化以及考虑使用 SUV _{max 的}其他示踪剂摄取指标来描述富含 ER 的乳腺癌至关重要。局限性包括不同 ER+ 乳腺癌疾病中 FES 摄取的变化以及排除后组织和腋窝区域。然而，FES-dbPET 具有很高的临床应用潜力，特别是在测量新辅助内分泌治疗的反应方面。需要进一步开发以改善视野并针对更大的 ER+ 乳腺癌患者队列进行研究。