We recently described a novel approach to measuring regional tumor oxygen tension using 19F pulse burst saturation recovery (PBSR) nuclear magnetic resonance (NMR) echo planar imaging (EPI) relaxometry of hexafluorobenzene. We now compare oxygen tension measurements in a group of size-matched R3327-AT1 Dunning prostate rat tumors made using this new method with those using a traditional polarographic method: the Eppendorf histograph. Similar oxygen tension distributions were found using the two methods, and both techniques showed that tumors with volume greater than 3.5 cm3 were significantly (P < 0.0001) less well oxygenated than smaller tumors (volume less than 2 cm3). Using the 19F EPI approach, we also examined the response to respiratory challenge. Increasing the concentration of inspired oxygen from 33% to 100% O2 produced a significant increase (P < 0.0001) in tumor oxygenation for a group of small tumors. In contrast, no change was observed in the mean pO2 for a group of large tumors. Consideration of individual tumor regions irrespective of tumor size showed a strong correlation between the maximum pO2 observed when breathing 100% O2 compared with mean baseline pO2. These results further demonstrate the usefulness of 19F EPI to assess changes in regional tumor oxygenation.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging