Noninvasive imaging of tumor redox status and its modification by tissue glutathione levels.

Therapeutic regimens such as radiation or chemotherapy attempt to exploit the physiological differences between normal and malignant tissue. Tissue redox status and pO(2) are two factors that are hypothesized to be different in normal and malignant tissues. Methods that can detect subtle differences in the above physiological parameters would greatly aid in devising appropriate treatment strategies. We have previously used in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging techniques and shown that tumor tissues are highly reducing and hypoxic compared with normal tissues (P. Kuppusamy et al., Cancer Res., 58: 1562-1568, 1998). The purpose of the present study was to obtain spatially…