Improving accuracy in multi-pinhole single-photon emission computed tomography

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Single-photon emission computed tomography (SPECT) is an imaging modality that is commonly used both pre-clinically and clinically. It provides serial non-destructive 3D imaging of organ function in living subjects in a wide range of species from mouse to human. Pre-clinical SPECT increases the efficiency of small-animal research and is used to improve our understanding of disease and to develop new diagnostic tests and treatments. However, for these types of studies, it is essential that the imaging data be very accurate and reproducible.***SPECT is used clinically to both diagnose and manage diseases like heart disease and cancer, the two leading causes of death in Canada. Newly introduced multi-pinhole cameras have both better sensitivity and better resolution, producing both clearer and less noisy images. However, pinhole collimators produce variable resolution, magnification, and sensitivity across the camera's field of view. The impact of multi-pinhole collimation on the spatial variability of image quality (accuracy and reproducibility) has not been assessed. In addition, new standardized methods are needed to routinely measure and evaluate how well these cameras are working.***The long-term goal of my program is to improve the quantitative accuracy and precision of imaging with multi-pinhole SPECT(/CT) imaging of the heart. My short-term objectives are: 1) To investigate the impact of variable sensitivity and resolution on image quality and lesion detectability in cardiac pinhole SPECT imaging, and develop methods to minimize the variability. 2) To use accurate scatter modeling to integrate information from the photopeak and lower energy windows, and thereby increase the signal-to-noise ratio of pinhole SPECT images. 3) To develop performance standards and quality assurance techniques to accurately measure the system model and performance of multi-pinhole SPECT cameras.******My lab's methods are to develop and validate advanced image reconstruction methods using analytic or Monte Carlo computer simulations. We evaluate our methods using physical phantom experiments which introduce the complexities of a real imaging environment. Finally, we test our techniques in animal models, or on human clinical data sets where possible and appropriate, to enable real-world translation of our research.******My lab provides a rich training environment for undergraduate and graduate student education. As part of the CAMPEP accredited Ottawa-Carleton joint program in medical physics, students interact with others engaged in a wide variety of medical physics projects. As part of the University of Ottawa Heart Institute, students are also exposed to the medical motivation that drives much of this field of research as well as to the broad multi-disciplinary nature of this field with exposure to research from microbiology to radiochemistry and tissue engineering.********