Grand Vally State University/ Van Andel Research Institute1, Small Animal Imaging, Grand Rapids, MI 49503 Van Andel Institute2, Grand Rapids, 49503
Purpose: Cerenkov radiation (CR) is the phenomenon that visible light is emitted when a charged particle, such as a β+ or β-, exceeds the speed of light in a medium through which it travels. Detection of the light can be achieved by an optical imager with appropriate sensitivity. The goal of this study is to develop standard protocols testing the feasibility of optical imagers for Cerenkov Luminescence Imaging, then to utilize the protocols to assess if the AMI-1000 is an appropriate device for Cerenkov Luminescence Imaging (CLI).
Methods: 2 positron (β+) emitters (18F, 64Cu) were used for this study. The linearity between optical radiance and radioactivity of these isotopes was investigated. Signal intensity of 18F and 64Cu across a uniform plate was investigated to gain understanding of the field of view (FOV) uniformity. Samples used in these studies were scanned by positron emission tomography (PET) to quantify and verify the correlation between PET and CLI. Lastly, this correlation was assessed for mice injected with 18F-FDG, a β+-emitter.
Results: The linearity tests of 18F and 64Cu yielded R2 values of 0.9988 and 0.9831 respectively. After normalization of experimental data to the Quantum Efficiency of the camera, it matched the expected spectral curve with an R2 of 0.9532 for 18F. Regressions for PET-CLI correlation in 18F was obtained to be 0.9944. The FOV was found to have 20% variance in regards to 64Cu. Based on our experimental findings in each of these areas, the AMI-1000 was found to be a viable optical imager for Cerenkov Luminescence Imaging.
[Abstract (DOCX)]