Figure 3.

(A) Chemical structure of the phosphorescent oxygen probe Oxyphor PtG4. (B) Excitation and emission spectra of Oxyphor PtG4 and the spectrum of Cherenkov radiation. (C) Oxygen quenching calibration curve of Oxyphor PtG4. (D-E) In vivo longitudinal pO₂ imaging of two tumor models over 5 days of fractionated radiotherapy. (F-G) Quantitative analysis of median pO₂ levels and hypoxic fraction changes during treatment. (H) Relative tumor volume changes normalized to baseline prior to radiotherapy. Adapted with permission from ⁸⁵, an open access article under a CC-BY 4.0 license, copyright 2020 Springer Nature.