Identification and elimination of reflection artifacts in biomedical photoacoustic imaging

Photoacoustic (PA) or optoacoustic imaging is a hybrid imaging modality that acoustically detects optical absorption contrast via the PA effect, a physical phenomenon that converts absorbed optical energy into acoustic energy. PA imaging is one of the fastest growing fields in biomedical optics, and has emerged as a powerful biomedical imaging modality in the last decade. Influence of acoustic inhomogeneities and resulting reflection artifacts is an important problem in PA imaging. These artifacts cause problems in image interpretation and significantly impact the contrast and imaging depth in any clinical applications of epi-mode or interstitial illumination PA imaging. The research presented in this thesis proposes a novel method called PAFUSion (photoacoustic-guided focused ultrasound) for identification and elimination of reflection artifacts in biomedical PA imaging. Potential of PAFUSion in epi-mode and interstitial illumination PA imaging is demonstrated in various chapters using simulations, phantom experiments, ex vivo studies, and in vivo measurements on human volunteers.