1H MRSI Maps of Tumor Hypoxia Using an Extrinsic Hypoxia Probe

Jess Pacheco-Torres^{1, 2}, Pilar Lopez-Larrubia¹, Elena Nieto³, Ramn Alajarn³, Julio lvarez-Builla³, Paloma Ballesteros², Sebastin Cerdn¹

Measurement of tumor oxygenation has gained importance in the last decades due to the known relationship between tumor hypoxia and tumor aggressiveness, poor outcome and resistance to therapies. Several techniques have been developed for this end (oxygen electrodes, EPR, PET) but none of them has gained widespread acceptance. 2-Nitroimidazole derivatives (EF5, Pimonidzole, ¹⁸F-MISO...) have been extensively used as molecular markers of hypoxia in combination with different techniques as immunohistochemistry, PET or ¹⁹F-MRI. Here we evaluate, for the first time to our knowledge, the use of these hypoxia markers in combination with ¹H-MRSI to generate oxygenation maps in vivo.