Clinical applications of in vivo EPR: Rationale and initial results

Abstract

In vivo electron paramagnetic resonance (EPR) has been very useful for studies in animals, and these results suggest that there are some very attractive potential applications in human subjects. In this article, we describe our rationale for the clinical application of in vivo EPR, some of the principal technical challenges, the initial results in human subjects, and our evaluation of the areas where in vivo EPR is likely to play an important clinical role in the near future. The most obvious area of very high potential for clinical applications is tissue oximetry, where in vivo EPR can provide repeated and accurate measurements of tissue pO₂, a type of measurement that cannot be obtained by other techniques. Oximetry is capable of providing clinicians with information that can impact directly on diagnosis and therapy, especially for peripheral vascular disease, oncology, and wound healing. The other area of great immediate importance is the ability of in vivo EPR to measure clinically significant exposures to ionizing radiation after the fact, which may occur due to accidents, terrorist activity, or nuclear war. The results obtained already from human subjects demonstrate the feasibility of the use of in vivo EPR for measurements in human subjects. We anticipate that in vivo EPR will play a vital role in the clinical management of various pathologies in the years to come.