MEASUREMENT OF TUMOR HYPOXIA IN SPONTANEOUS CANINE SARCOMAS |
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| Authors: | Matthias Bruehlmeier Barbara Kaser-Hotz Roger Achermann Carla Rohrer Bley Melanie Wergin Pius A Schubiger Simon M Ametamey |
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| Institution: | Section of Diagnostic Imaging and Radiation Oncology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. matthias.bruehlmeier@ksa.ch |
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| Abstract: | We used positron emission tomography (PET) with 18F]fluoromisonidazole (18F]FMISO) to study tumor hypoxia in six dogs with spontaneous sarcomas. The tumors were regarded as hypoxic if 18F]FMISO uptake exceeded normal tissue radioactivity by 40% (tumor/muscle ratio > 1.4) or if kinetic analysis indicated a positive 18F]FMISO tissue influx rate (Ki > 0) by a Patlak plot. Using these criteria, we found hypoxia in a fibrosarcoma grade II, an undifferentiated sarcoma, and an ostoeosarcoma, but not in a fibrosarcoma grade I, another osteosarcoma, and a myxosarcoma. In three animals, the tumor oxygen partial pressure (pO2) was also measured invasively using Eppendorf needle electrodes. In these cases, the Eppendorf measurements were confirmed by the 18F]FMISO PET results. In addition, 15O]H2O PET was performed in four dogs in order to assess tumor perfusion. Comparisons of the 18F]FMISO with 15O]H2O PET images in two cases showed that tumor hypoxia occurred in the tumor center with low perfusion, whereas perfusion was heterogeneous in a nonhypoxic tumor. |
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| Keywords: | [18F]fluoromisonidazole hypoxia positron emission tomography spontaneous canine sarcoma |
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