New York Medical College, School of Medicine, New York, NY, USA.
Department of Radiation Oncology, City of Hope National Medical Center, 1500 E Duarte Road, Duarte, CA, 91010, USA.
Radiat Oncol. 2024 Sep 18;19(1):124. doi: 10.1186/s13014-024-02502-w.
Biology-guided radiotherapy (BgRT) is a novel radiation delivery approach utilizing fluorodeoxyglucose (FDG) activity on positron emission tomography (PET) imaging performed in real-time to track and direct RT. Our institution recently acquired the RefleXion X1 BgRT system and sought to assess the feasibility of targeting metastatic sites in various organs, including the liver. However, in order for BgRT to function appropriate, adequate contrast in FDG activity between the tumor and the background tissue, referred to as the normalized SUV (NSUV), is necessary for optimal functioning of BgRT.
We reviewed the charts of 50 lung adenocarcinoma patients with liver metastases. The following variables were collected: SUVmax and SUVmean for each liver metastasis, SUVmean and SUVmax at 5 and 10 mm radially from the lesion, and NSUV at 5 mm and 10 mm (SUVmax of the liver metastasis divided by SUV mean at 5 mm at 10 mm respectively).
82 measurable liver metastases were included in the final analysis. The average SUVbackground of liver was 2.26 (95% confidence interval [CI] 2.17-2.35); average SUVmean for liver metastases was 5.31 (95% CI 4.87-5.75), and average SUVmax of liver metastases was 9.19 (95% CI 7.59-10.78). The average SUVmean at 5 mm and 10 mm radially from each lesion were 3.08 (95% CI 3.00-2.16) and 2.60 (95% CI 2.52-2.68), respectively. The mean NSUV at 5 mm and 10 mm were 3.13 (95% CI 2.53-3.73) and 3.69 (95% CI 3.00-4.41) respectively. Furthermore, 90% of lesions had NSUV greater than 1.45 at 5 mm and greater than 1.77 at 10 mm.
This is the first study to comprehensively characterize FDG contrast between the liver tumor and background, referred to as NSUV. Due to the high background SUV normally found in the liver, this work will be valuable for guiding optimization of BgRT for treating liver metastases in the future using the RefleXion X1 and potentially other similar BgRT platforms.
生物学引导放疗（BgRT）是一种利用实时进行的正电子发射断层扫描（PET）成像上的氟脱氧葡萄糖（FDG）活性来跟踪和指导放疗的新型放射治疗方法。我们医院最近购买了 RefleXion X1 BgRT 系统，并试图评估在各种器官（包括肝脏）中靶向转移部位的可行性。然而，为了使 BgRT 正常运行，肿瘤和背景组织之间的 FDG 活性需要有足够的对比度，称为标准化 SUV（NSUV），这对于 BgRT 的最佳功能是必要的。
我们回顾了 50 例患有肝转移的肺腺癌患者的图表。收集了以下变量：每个肝转移灶的 SUVmax 和 SUVmean，距病变 5 和 10mm 处的 SUVmean 和 SUVmax，以及 5mm 和 10mm 处的 NSUV（肝转移灶的 SUVmax 除以 5mm 和 10mm 处的 SUVmean）。
最终分析中包括 82 个可测量的肝转移灶。肝脏的平均 SUVbackground 为 2.26（95%置信区间[CI]2.17-2.35）；肝转移灶的平均 SUVmean 为 5.31（95%CI4.87-5.75），肝转移灶的平均 SUVmax 为 9.19（95%CI7.59-10.78）。距每个病变 5mm 和 10mm 处的 SUVmean 分别为 3.08（95%CI3.00-2.16）和 2.60（95%CI2.52-2.68）。5mm 和 10mm 处的平均 NSUV 分别为 3.13（95%CI2.53-3.73）和 3.69（95%CI3.00-4.41）。此外，90%的病变在 5mm 处的 NSUV 大于 1.45，在 10mm 处的 NSUV 大于 1.77。
这是第一项全面描述肝脏肿瘤与背景之间的 FDG 对比度的研究，称为 NSUV。由于肝脏中通常存在较高的背景 SUV，因此这项工作对于指导未来使用 RefleXion X1 和可能的其他类似 BgRT 平台治疗肝转移的 BgRT 优化将非常有价值。
