Deuterated trityl spin probe for in vivo pO2 imaging with improved precision using Time-Domain EPR

Due to the narrow linewidth and slower signal decay, it was expected that Ox071 is suitable for wide range pO2 estimation. In this work, we present our first 3D in vivo EPR oximetry using Ox071 in comparison with Ox063. EPR imaging of MIA Paca-2 tumor and healthy kidneys were performed on successive days by using either Ox071 or Ox063, resulting in similar spin density, pO2 maps, and pO2 histograms in the tumor regions and more homogeneous pO2 profile with Ox071 in kidney compared with Ox063. The result suggested that Ox071 is applicable for oximetry in tissue at higher pO2.