CHAPTER 10: Photoacoustic Imaging of Oxygen

Molecular oxygen (O₂) is of paramount importance in biomedical science; thus monitoring O₂ has been a research focus for decades, and various methods to measure and image oxygen have been reported. In this chapter, we introduce O₂ monitoring and imaging through photoacoustic (PA) spectroscopy. Because PA imaging is directly correlated with optical absorption, it has been first utilized for direct measurements of oxy- and deoxy- hemoglobin and/or other oxygen carrying proteins for indirect O₂ monitoring. More recently, tissue O₂ monitoring by PA was introduced, by the PALT (PA lifetime) method, using the same mechanism as conventional phosphorescence quenching based oxygen sensing. The theoretical backgrounds as well as some recent examples of PA oxygen monitoring are introduced.