A novel sensor for high throughput preclinical radiotracer imaging

Preclinical imaging is a cornerstone of translational research, as all therapeutic drugs need to be tested for efficacy and toxicity on animals prior to human trials. Optical imaging techniques, such as bioluminescence and multispectral fluorescence imaging, currently dominate preclinical functional imaging despite their depth dependent limitations on quantitation and sensitivity. Translating drugs developed with these techniques to clinical models can therefore be difficult. Hence, clinically relevant nuclear imaging techniques, such as SPECT and PET, are therefore becoming increasingly used in preclinical imaging. Dedicated preclinical SPECT and PET systems are now available, but for many preclinical research groups this requires a significant investment in new equipment. We demonstrate a method to acquire high resolution planar images with a SPECT radiotracer by retrofitting a IVIS Spectrum (Caliper Life Sciences) optical imaging system with a pinhole collimator and a large area CsI:Tl scintillator with a novel morphology. We report on the development of a novel thick, transparent, crystalline microcolumnar CsI:Tl scintillator structure (Crystalline Microcolumnar Structure (CMS) scintillator) that simultaneously provides high ?-ray absorption efficiency, high intrinsic spatial resolution, and bright light emission. We present animal and phantom images acquired using a 4 mm thick, 15 cm diameter scintillator and a 2 mm diameter tungsten pinhole collimator with a IVIS Spectrum. The ability to use an existing commercial preclinical optical imaging system to rapidly acquire planar gamma ray images with good spatial resolution of one or multiple animals would be a new and useful tool for high throughput screening of molecular imaging probes.