Development of Photoacoustic Imaging Technologies for Biomedical Applications

Abstract

Photoacoustic imaging (PAI) is an emerging modality based on the acoustic detection of optical absorption. Since acoustic scattering in tissue is much less than that of light, the conversion of light absorption into sound allows PAI to overcome the light diffusion limit and reveal optical absorption deep inside the tissue, at a high spatial resolution. After its first demonstration of functional imaging in small animals about a decade ago, PAI has been developed rapidly and become one of the fastest growing biomedical imaging modalities. Rely on non-ionizing light illumination and rich endogenous or exogenous optical contrasts, PAI possesses advantages in term of safety, penetration depth, and tissue contrast. In this dissertation, substantial efforts have been made to further facilitate the development of PAI in the following three aspects: spatial resolution improvement, light illumination optimization, and advanced biomedical applications. There are 8 chapters in this dissertation. Chapter 1 is the introduction, which introduces backgrounds of PAI and briefly summarized the topics of this dissertation. Chapter 2 and Chapter 3 present the slit technique, which enables linear array-based PAI system to achieve near isotropic spatial resolution in three dimensions. Optimization in light illumination is introduced in Chapter 4. Chapter 5, Chapter 6, and Chapter 7 introduce three advanced biomedical applications of PAI: palm vessel biometrics (Chapter 5), breast imaging (Chapter 6), and wound assessment (Chapter 7). Conclusion and future directions are presented in Chapter 8. With promising results shown in this dissertation, PAI is expected to find great applications in the biomedical area.