Imaging Sound and Light: A Novel Photoacoustic Volume Imaging System for the Assessment of Suspicious Skin Lesions
AdvisorWitte, Russell S.
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractSkin cancer is the most prevalent type of cancer in the United States, emphasizing the needfor noninvasive and real-time clinical imaging for lesion evaluation and response to non-surgical therapies, particularly for lesions with deeper dermal components. Optical imaging modalities currently available have limitations in differentiating between healthy tissue and various types of skin cancers deep within the tissue, such as basal and squamous cell carcinomas and aggressive melanomas. To address this challenge, photoacoustic tomography (PAT) has emerged as a promising modality as it provides specificity in tissue structure and composition related to functional data at depths of 1 cm or greater. However, traditional PAT systems only offer 2D cross-sectional images using standard linear arrays, making multi-spectral 3D volume imaging highly desirable. This dissertation presents the development and testing of a cost-effective, mobile clinical hybrid pulse-echo (PE) + photoacoustic tomography (PAT) 3D imaging system for in-vivo assessment and monitoring of common cutaneous skin lesions in dermatology clinical use. This system offers high-resolution volume images (∼200 μm) that provide information on both tissue structure and material composition, enabling clinicians to make accurate diagnosis and treatment decisions. The system achieves this by converting a conventional linear ultrasound array to perform 3D volume PE and PAT scans that is capable of performing spectroscopy within the near infrared range (680 nm- 1000 nm), providing additional material-specific information. In this dissertation, the optoacoustic design considerations that led to novel methods for integrating light and sound for both traditional ultrasound and photoacoustic imaging are discussed. The innovative ways for coupling the device to tissue, which enables repeatable, hands-free assessment during imaging sessions, are highlighted. The system’s capabilities as a clinical imaging system are demonstrated by presenting in-vivo data from human subjects. Proof-of-concept studies reveal variations in acoustic and optical properties between common cutaneous lesions and assess their material composition measured from the system’s photoacoustic spectroscopic capabilities. The system has the potential for clinical use, enabling clinicians to examine, monitor, and characterize suspicious skin lesions with high resolution and accuracy. In addition to improving diagnostic accuracy, the proposed system can help reduce the need for invasive biopsies, ultimately leading to better patient outcomes and reduced healthcare costs.
Degree ProgramGraduate College