Folate Receptor Imaging with 125I Labeled Folic Acid with a Whole Body Small Animal Imaging Device Built with Plastic Scintillating Optical Fibers

A small animal whole body imaging cylindrical device was built with plastic scintillating fibers and position sensitive photomultipliers (Hamamatsu) and digitized using flash ADCs. A co-axial brass mesh collimator (septum thickness 1 mm) was used in combination with an electronic collimation scheme to enhance spatial resolution. Imaging studies with 125I labeled folic acid were performed in mice bearing folate receptor +ve (IGROV) tumor and receptor −ve (Meth-A) tumor. In-situ imaging of animals sacrificed at 15–30 min post injection of the tracer showed the localization of the tumor in animals with the folate receptor +ve tumors. Our initial studies demonstrate the utility of a device built with plastic scintillating fibers in small animal imaging studies with low energy photons (25–35 keV).