PET for Molecular Imaging of Small Animals

Thakur, Mathew

Abstract

The importance of small animal positron emission tomography (PET) and single photon emission tomography (SPECT) in biomedical molecular imaging research cannot be over-emphasized. The ability to image small animals without sacrificing them has significant potential for longitudinal studies. Our institution acquired a Philips Mosaic PET scanner just over three years ago that has enhanced the ability of several researchers at Thomas Jefferson University to objectively and quantitatively evaluate their hypotheses without having to sacrifice scores of rodents in oncologic, cardiologic and neurologic investigations. However, it has become apparent that the low sensitivity (1.3%) and poor spatial resolution (2.2 mm) of the Mosaic PET scanner has compromised the investigators' ability to perform adequate imaging studies for meaningful conclusions. Further, we have recognized the necessity of SPECT imaging in small animals to complement PET. This proposal pertains to a high resolution (~1.0 mm), high sensitivity (>10%) state-of- the-art small animal PET scanner, to enhance our existing facility. We have chosen to request a Siemens Inveon 120 scanner because of its high sensitivity, high resolution, and compact design afforded primarily by the use of the state of the art technology and LSO crystals. With the availability of Inveon 120, we intend to maximize the benefit to our investigators, by converting the Mosaic into a high resolution (< 1 mm), high sensitivity (> 0.5%) multi-pinhole SPECT machine. Our ability to convert an animal PET system into a SPECT scanner not only enhances our research capability several-fold but also promises to provide a new tool for researchers in molecular imaging. The commercial availability of many useful positron emitting radionuclides, such as 64Cu, 124I, 68Ga and 18F, and SPECT radionuclides, such as 99mTc, 111In and 123I, permits us to prepare many novel biomolecules for molecular imaging. Projects benefiting from the new Inveon 120 scanner include; studies of stem cell implants in neurodegenerative disease, studies of oncogene expression in breast cancer, investigations of novel drugs for the treatment of Alzheimer's disease, studies of myocardial regeneration, evaluation of biomarkers for colorectal cancer, and measurement of oncogenes in prostate and colorectal cancers. Close collaborations with the Kimmel Cancer Center and the Farber Institute for Neurosciences will be enhanced considerably with the acquisition of this scanner. Translational biomedical research, in which discoveries made in the laboratory are translated to clinical diagnosis and treatment, relies heavily on molecular imaging. The proposed small animal PET and SPECT scanners in this application would enable biomedical researchers to perform non-invasive molecular imaging in a variety of disease models, with direct application to clinical human studies. ? ? ?