Hypoxia-imaging with 18F-Misonidazole and PET: Changes of kinetics during radiotherapy of head-and-neck cancer

• Published in: Radiotherapy and oncology Vol. 83; no. 3; pp. 406 - 410
• Main Authors: Eschmann, Susanne Martina, Paulsen, Frank, Bedeshem, Claudia, Machulla, Hans-Jürgen, Hehr, Thomas, Bamberg, Michael, Bares, Roland
• Format: Journal Article
• Language: English
• Published: Elsevier Ireland Ltd 01.06.2007
• Subjects: 18F-Misonidazole-PET; Head-and-neck cancer; Kinetics; Radiotherapy; Head-and-neck cancer; Kinetics; 18F-Misonidazole-PET; Radiotherapy
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2007.05.014

PET with 18F-Misonidazole (FMISO-PET) is a non-invasive method for measuring tumor hypoxia. We analysed changes of FMISO-uptake during radiotherapy and their impact on patient outcome. Fourteen patients with HNC underwent repeated FMISO-PET prior to radiotherapy and after 30 Gy. Dynamic and static PET-scans (2 + 4 h p.i.) were acquired. FMISO-uptake was quantified by calculating standard uptake values (SUV) and tumor-muscle-ratios (TMR). Kinetic curve types representing tissue hypoxia were defined. Change of curve type was correlated with patient outcome. The mean SUV 4 h p.i. and the TMR decreased significantly during radiotherapy. SUV decreased clearly in 12/14 patients, and increased in 2 patients. TMR decreased in 11 patients, and increased in 3 patients. Prior to radiotherapy, three different shapes of kinetic curve types indicative for the degree of hypoxia could be defined in 12/14 patients: (1) accumulation type (severe hypoxia ( n = 8)), (2) intermediate type (intermediate degree of hypoxia ( n = 3)), and (3) wash-out type (low degree of hypoxia ( n = 1)). Curve type changed towards a lower degree of hypoxia at 30 Gy in all but 3 patients. In three patients curve type remained unchanged. The changes in tumor FMISO-uptake during radiotherapy indicate radio-induced reoxygenation.