Brown adipose tissue (BAT) is important in monitoring energy homeostasis and cancer cachexia. Different from white adipose tissue, BAT is characterized by the presence of a large number of mitochondria in adipocytes. Translocator protein 18 kDa (TSPO), a critical transporter, is expressed in the outer membrane of mitochondria. We speculated that [¹⁸F]DPA714, a specific TSPO tracer, may monitor BAT activity in tumor-bearing mice in vivo. We first analyzed the radioactive uptake of positron emission tomography (PET) tracers in BAT of CT26 xenograft mice with 18F-fluorodeoxyglucose ([¹⁸F]FDG) and [¹⁸F]DPA714. We also studied the BAT uptake of [¹⁸F]DPA714 in CT26, A549 and LLC tumor models. The dynamic distribution of [¹⁸F]FDG is quite variable among animals, even in mice of the same tumor model (%ID/g-mean: mean ± SDM, 8.61 ± 8.90, n = 16). Contrarily, [¹⁸F]DPA714 produced high-quality and stable BAT imaging in different tumor models and different animals of the same model. Interestingly, %ID/g-mean of [¹⁸F]DPA714 in BAT was significantly higher on day 26 than that on day 7 in CT26 xenograft model. Taken together, these results strongly indicate the potential feasibility of [¹⁸F]DPA714 PET imaging in investigating BAT and energy metabolism during tumor progression in preclinical and clinical study.

棕色脂肪组织（BAT）在监测能量稳态和癌症恶病质中很重要。与白色脂肪组织不同，BAT的特征在于脂肪细胞中存在大量线粒体。转运蛋白18 kDa（TSPO），一种重要的转运蛋白，在线粒体的外膜中表达。我们推测[ ¹⁸ F] DPA714，一种特定的TSPO示踪剂，可以监测体内荷瘤小鼠的BAT活性。我们首先分析了用18F-氟脱氧葡萄糖（[ ¹⁸ F] FDG）和[ ¹⁸ F] DPA714在CT26异种移植小鼠的BAT中对正电子发射断层扫描（PET）示踪剂的放射性吸收。我们还研究了CT26，A549和LLC肿瘤模型中[ ¹⁸ F] DPA714的BAT吸收。[ ¹⁸即使在具有相同肿瘤模型的小鼠中，F] FDG在动物之间也存在很大差异（％ID / g均值：平均值±SDM，8.61±8.90，n = 16）。相反，[ ¹⁸ F] DPA714在不同的肿瘤模型和同一模型的不同动物中产生了高质量且稳定的BAT成像。有趣的是，在第26天，BAT中[ ¹⁸ F] DPA714的％ID / g-均值显着高于在CT26异种移植模型中的第7天。综上所述，这些结果强烈表明[ ¹⁸ F] DPA714 PET成像在临床前和临床研究中研究肿瘤进展过程中的BAT和能量代谢的潜在可行性。