|dc.description.abstract||Photoacoustic (PA) imaging is a hybrid biomedical imaging technique that can acoustically monitor optical absorption distribution in biological tissues through the PA effect. After pulsed laser excitation, chromophores that absorb light energy generate ultrasound (US) signals through thermal-elastic expansion. Then the ultrasound signals can be detected with ultrasound transducer. By combining optical and US imaging technique, PA imaging can provide high resolution images in deeper biological tissues than other optical imaging techniques. By carefully selecting excitation laser wavelength, PA imaging can provide anatomical and functional information including hemoglobin oxygen saturation, blood flow, and temperature. Additionally, X-ray induced acoustic (XA) imaging techniques using X-rays with shorter wavelengths than optical lasers can provide X-ray distribution inside biological tissues. Thanks to these advantages, PA and XA imaging have been widely studied in molecular imaging, drug delivery, and treatment monitoring. The main goal of this dissertation is to develop multimodal optical and acoustical imaging systems including PA and optical coherence tomography (OCT), PA and US, X-ray induced acoustic imaging, and molecular PA imaging systems. The specific aims include (1) to develop a combined PA and OCT system for intraoperative imaging purposes; (2) to develop a combined PA and US imaging system for dental applications; (3) to develop a 3D volumetric XA computed tomography system. In the first part of this thesis, multimodal imaging systems using PA, OCT, US, and X-ray are introduced. At first, a combined PA and OCT imaging is introduced. By combining PA microscopy (PAM), OCT, and surgical microscopy, the system can acquire enlarged surface images, PA images based on light absorption, and OCT images based on light scattering simultaneously in real-time. With the developed system, in vivo melanoma resection surgery was monitored. The results show the potential applications in neurosurgery, ophthalmological surgery, and other microsurgeries. As another multimodal imaging system, a combined PA and US imaging is introduced. By adopting a pulsed laser, PA imaging can be easily combined with US imaging. With the developed system, PA and US images of implant embedded porcine jawbone was acquired. The results show the potential clinical application of PA and US imaging for dental implant treatment. As another multimodal imaging system, X-ray induced acoustic computed tomography is introduced. Using a pulsed X-ray source and an arc shaped US array transducer, the developed system can provide 3D volumetric XACT images. Additionally, a 3D back-projection software based on graphics processor unit (GPU) processing was developed. The developed software enhanced execution time approximately 40 times compared with that of CPU based software. The results show that the developed XACT system can be a potential tool to monitor high-resolution X-ray dose distribution and image X-ray absorbing structures inside biological tissues. In the second part of this thesis, molecular PA imaging is introduced. Hyaluronic-acid conjugated silica nanoparticles (HA-SiNP) were developed as a liver targeted PA contrast agent. Then the in vivo liver targeting process was monitored for 48 hours with an acoustic resolution PA microscopy (AR-PAM). The results show the high liver targeting efficiency of the HA-SiNP and possibility of the HA-SiNP conjugates as a biocompatible PA contrast agent, especially for the liver targeting. In the last part, the dissertation summarizes the research, and discusses future works. By exploring multimodal imaging systems and molecular PA imaging, the dissertation could provide useful research platforms for further studies.||-|
|dc.title||다중모드의 분자 광학 및 음향 영상||-|
|dc.title.alternative||Multimodal Molecular Optical and Acoustical Imaging||-|
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