Developing in vivo EPR oximetry for clinical use.

This paper describes the rationale for carrying out electron paramagnetic resonance (EPR) oximetry studies in human subjects in the clinical setting and the potential approaches and specific steps needed to make such studies feasible and useful. While the approach is described specifically for EPR oximetry, many of the principles may apply to the initial clinical uses of other techniques. The suggested operational approach is to have the initial applications occur in as clinically useful and simple a manner as possible, with the expectation that once the technique is introduced and accepted in the clinical setting, that more complex and/or more technically difficult applications will be able to be developed. The initial approach will be based on EPR spectroscopy at 1.2 GHz focusing on applications for which in vivo EPR provides a clearly useful approach to important clinical problems for which currently there is no good alternative method. The EPR measurements can be carried out non-invasively by measurements within 10 mm of the surface after the placement of the paramagnetic material at the site of interest, or by the placement of a needle/catheter in the site of interest for the required time period. The suggested initial clinical applications are guiding therapy for individual patients with tumors or vascular disease, by direct measurements of tissue pO2.