Di Perri Dario, Lee John A, Bol Anne, Hanin François-Xavier, Janssens Guillaume, Labar Daniel, Robert Annie, Sterpin Edmond, Geets Xavier
a Center of Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Expérimentale et Clinique (IREC) , Université catholique de Louvain , Brussels , Belgium.
b Department of Radiation Oncology , Cliniques universitaires Saint-Luc , Brussels , Belgium.
Acta Oncol. 2017 Sep;56(9):1181-1188. doi: 10.1080/0284186X.2017.1329594. Epub 2017 May 24.
PET-guided dose painting (DP) aims to target radioresistant tumour regions in order to improve radiotherapy (RT) outcome. Besides the well-known [F]fluorodeoxyglucose (FDG), the hypoxia positron emission tomography (PET) tracer [F]fluoroazomycin arabinoside (FAZA) could provide further useful information to guide the radiation dose prescription. In this study, we compare the spatial distributions of FDG and FAZA PET uptakes in lung tumours.
Fourteen patients with unresectable lung cancer underwent FDG and FAZA 4D-PET/CT on consecutive days at three time-points: prior to RT (pre), and during the second (w2), and the third (w3) weeks of RT. All PET/CT were reconstructed in their time-averaged midposition (MidP). The metabolic tumour volume (MTV: FDG standardised uptake value (SUV) > 50% SUV), and the hypoxic volume (HV: FAZA SUV > 1.4) were delineated within the gross tumour volume (GTV). FDG and FAZA intratumoral PET uptake distributions were subsequently pairwise compared, using both volume-, and voxel-based analyses.
Volume-based analysis showed large overlap between MTV and HV: median overlapping fraction was 0.90, 0.94 and 0.94, at the pre, w2 and w3 time-points, respectively. Voxel-wise analysis between FDG and FAZA intratumoral PET uptake distributions showed high correlation: median Spearman's rank correlation coefficient was 0.76, 0.77 and 0.76, at the pre, w2 and w3 time-points, respectively. Interestingly, tumours with high FAZA uptake tended to show more similarity between FDG and FAZA intratumoral uptake distributions than those with low FAZA uptake.
In unresectable lung carcinomas, FDG and FAZA PET uptake distributions displayed unexpectedly strong similarity, despite the distinct pathways targeted by these tracers. Hypoxia PET with FAZA brought very little added value over FDG from the perspective of DP in this population.
正电子发射断层扫描（PET）引导的剂量绘画（DP）旨在靶向放射抗性肿瘤区域，以改善放射治疗（RT）效果。除了广为人知的[F]氟脱氧葡萄糖（FDG）外，缺氧正电子发射断层扫描（PET）示踪剂[F]氟阿糖胞苷（FAZA）可为指导放射剂量处方提供更多有用信息。在本研究中，我们比较了肺肿瘤中FDG和FAZA PET摄取的空间分布。
14例不可切除肺癌患者在连续3天的三个时间点接受了FDG和FAZA 4D-PET/CT检查：放疗前（pre）、放疗第2周（w2）和放疗第3周（w3）。所有PET/CT均在其时间平均中间位置（MidP）重建。在大体肿瘤体积（GTV）内勾勒出代谢肿瘤体积（MTV：FDG标准化摄取值（SUV）>50%SUV）和缺氧体积（HV：FAZA SUV>1.4）。随后，使用基于体积和体素的分析方法，对FDG和FAZA肿瘤内PET摄取分布进行两两比较。
基于体积的分析显示MTV和HV之间有很大重叠：在pre、w2和w3时间点，重叠分数中位数分别为0.90、0.94和0.94。FDG和FAZA肿瘤内PET摄取分布的体素分析显示高度相关：在pre、w2和w3时间点，Spearman等级相关系数中位数分别为0.76、0.77和0.76。有趣的是，与FAZA摄取低的肿瘤相比，FAZA摄取高的肿瘤在FDG和FAZA肿瘤内摄取分布之间往往表现出更多相似性。
在不可切除的肺癌中，尽管这些示踪剂靶向的途径不同，但FDG和FAZA PET摄取分布显示出出乎意料的高度相似性。从DP的角度来看，在该人群中，使用FAZA进行缺氧PET检查比使用FDG几乎没有额外价值。
