Hypoxia imaging with the nitroimidazole18 F-FAZA PET tracer: A comparison with OxyLite, EPR oximetry and19 F-MRI relaxometry

• Published in: Radiotherapy and oncology 2012, Vol.105 (1), p.29-35
• Main Authors: Tran, Ly-Binh-An, Bol, Anne, Labar, Daniel, Jordan, Bénédicte, Magat, Julie, Mignion, Lionel, Grégoire, Vincent, Gallez, Bernard
• Format: Article
• Language: English
• Subjects: Hematology, Oncology and Palliative Medicine
• ISSN: 0167-8140
• DOI: 10.1016/j.radonc.2012.04.011

Abstract Background and purpose18 F-FAZA is a nitroimidazole PET tracer that can provide images of tumor hypoxia. However, it cannot provide absolute pO2 values. To qualify18 F-FAZA PET, we compared PET images to pO2 measured by OxyLite, EPR oximetry and19 F-MRI. Materials and methods Male WAG/Rij rats grafted with rhabdomyosarcoma were used. Tumor oxygenation was modified by gas breathing (air or carbogen). The same day of PET acquisition, the pO2 was measured in the same tumor either by OxyLite probes (measurement at 10 different sites), EPR oximetry using low frequency EPR or19 F-relaxometry using 15C5 on an 11.7 T MR system. Results There was a good correlation between the results obtained by PET and EPR ( R = 0.93). In the case of OxyLite, although a weaker correlation was observed ( R = 0.55), the trend for two values to agree was still related to the inverse function theoretically predicted. For the comparison of18 F-FAZA PET and19 F-MRI, no change in T1 was observed. Conclusions A clear correlation between18 F-FAZA PET image intensities and tumor oxygenation was demonstrated, suggesting that18 F-FAZA PET is a promising imaging technique to guide cancer therapy.