Unspecific bone uptake (UBU) related to [¹⁸F]PSMA-1007 PET/CT imaging represents a clinical challenge. We aimed to assess whether a combination of clinical, biochemical, and imaging parameters could predict skeletal metastases in patients with [¹⁸F]PSMA-1007 bone focal uptake, aiding in result interpretation. Methods: We retrospectively analyzed [¹⁸F]PSMA-1007 PET/CT performed in hormone-sensitive prostate cancer (PCa) patients at 3 tertiary-level cancer centers. A fourth center was involved in performing an external validation. For each, a volume of interest was drawn using a threshold method to extract SUV_max, SUV_mean, PSMA tumor volume, and total lesion PSMA. The same volume of interest was applied to CT images to calculate the mean Hounsfield units (HU_mean) and maximum Hounsfield units. Clinical and laboratory data were collected from electronic medical records. A composite reference standard, including follow-up histopathology, biochemistry, and imaging data, was used to distinguish between PCa bone metastases and UBU. PET readers with less (n = 2) or more (n = 2) experience, masked to the reference standard, were asked to visually rate a subset of focal bone uptake (n = 178) as PCa metastases or not. Results: In total, 448 bone [¹⁸F]PSMA-1007 focal uptake specimens were identified in 267 PCa patients. Of the 448 uptake samples, 188 (41.9%) corresponded to PCa metastases. Ongoing androgen deprivation therapy at PET/CT (P < 0.001) with determination of SUV_max (P < 0.001) and HU_mean (P < 0.001) independently predicted bone metastases. A composite prediction score, the bone uptake metastatic probability (BUMP) score, achieving an area under the receiver-operating-characteristic curve (AUC) of 0.87, was validated through a 10-fold internal and external validation (n = 89 bone uptake, 51% metastatic; AUC, 0.92). The BUMP score’s AUC was significantly higher than that of HU_mean (AUC, 0.62) and remained high among lesions with HU_mean in the first tertile (AUC, 0.80). A decision-curve analysis showed a higher net benefit with the score. Compared with the visual assessment, the BUMP score provided added value in terms of specificity in less-experienced PET readers (88% vs. 54%, P < 0.001). Conclusion: The BUMP score accurately distinguished UBU from bone metastases in PCa patients with [¹⁸F]PSMA-1007 focal bone uptake at PET imaging, offering additional value compared with the simple assessment of the osteoblastic CT correlate. Its use could help clinicians interpret imaging results, particularly those with less experience, potentially reducing the risk of patient overstaging.

与 [ ¹⁸ F]PSMA-1007 PET/CT 成像相关的非特异性骨摄取 (UBU) 是一项临床挑战。我们的目的是评估临床、生化和成像参数的组合是否可以预测 [ ¹⁸ F]PSMA-1007 骨灶摄取患者的骨骼转移，从而帮助结果解释。方法：我们回顾性分析了 3 个三级癌症中心对激素敏感型前列腺癌 (PCa) 患者进行的 [ ¹⁸ F]PSMA-1007 PET/CT。第四个中心参与执行外部验证。对于每个肿瘤，使用阈值方法绘制感兴趣的体积，以提取 SUV _max 、SUV_平均值、PSMA 肿瘤体积和总病变 PSMA。将相同的感兴趣体积应用于 CT 图像，以计算平均 Hounsfield 单位 ( _HUmean ) 和最大 Hounsfield 单位。从电子病历中收集临床和实验室数据。使用综合参考标准（包括后续组织病理学、生物化学和影像数据）来区分 PCa 骨转移和 UBU。经验较少 ( n = 2) 或较多 ( n = 2) 的 PET 阅片员被要求以视觉方式将局灶性骨摄取的子集 ( n = 178) 评估为 PCa 转移与否。结果：总共在 267 名 PCa 患者中鉴定出 448 个骨 [ ¹⁸ F]PSMA-1007 局灶性摄取标本。在 448 个摄取样本中，188 个 (41.9%) 对应于 PCa 转移。正在进行 PET/CT 雄激素剥夺治疗 ( P < 0.001)，并确定 SUV _max ( P < 0.001) 和 HU_平均值( P < 0.001)。001）独立预测骨转移。综合预测评分，即骨摄取转移概率 (BUMP) 评分，接受者操作特征曲线下面积 (AUC) 为 0.87，通过 10 倍内部和外部验证进行验证（ n = 89 骨摄取， 51% 转移；AUC，0.92）。 BUMP 评分的 AUC 显着高于 HU_平均值（AUC，0.62），并且在 HU_平均值位于第一个三分位数的病变中保持较高水平（AUC，0.80）。决策曲线分析显示，分数带来更高的净收益。与视觉评估相比，BUMP 评分在经验较少的 PET 读者中提供了特异性方面的附加值（88% vs. 54%， P < 0.001）。结论：在 PET 成像中，BUMP 评分可以准确地区分具有 [ ¹⁸ F]PSMA-1007 局部骨摄取的 PCa 患者的 UBU 和骨转移，与成骨细胞 CT 相关性的简单评估相比，提供了额外的价值。它的使用可以帮助临床医生解释成像结果，特别是那些经验较少的临床医生，从而可能降低患者过度分期的风险。