The apparent diffusion constant measured by mri correlates with po₂ in a rif‐1 tumor

As tissue oxygen tension (pO₂ is an important variable in cancer therapy, it would be of major clinical benefit to be able to measure pO₂ noninvasively. Current methods for determining pO₂ in clinical settings are limited to superficial tumors. The authors measured the apparent diffusion constant (ADC) in an implanted murine fibrosarcoma (RIF‐1) using magnetic resonance imaging and correlated the ADC with tissue pO₂ measured by electron paramagnetic resonance oximetry. The ADC correlates significantly with tissue pO₂ in this tumor (r = 0.89; n = 14) and so may provide a noninvasive index of pO₂ in tumors.