Figure 3.

In vivo data collected at 3T. A T₂ weighted anatomic image (A), pH image of the same slice demonstrating the distribution of pH calculated (B), spectra for the corresponding voxels shown in the T2 weighted image (C) and the Lactate/Pyruvate ratio image (D) are shown for a TRAMP tumor bearing mouse. The tumor is visible in the upper half of the slice. Following dissolution, 300 µL of a solution 55 mM in pre-polarized ¹³C bicarbonate and 10 mM in ¹³C pyruvate were injected intravenously. Data was acquired with a resolution of 1 cm³. The pH for individual voxels was calculated using the Henderson-Hasselbalch equation and pK_a of 6.17 at 37° C. The peak ratios of observed ¹³C lactate to ¹³C pyruvate are also shown beneath the corresponding spectra. Regions of the CO₂ resonance have been scaled up to demonstrate the signal-to-noise achieved in each voxel.