An ultrahigh resolution SPECT system for I-125 mouse brain imaging studies

This paper presents some initial experimental results obtained with a dual-head prototype single photon emission microscope system (SPEM) that is dedicated to mouse brain studies using I-125 labeled radiotracers. In particular, this system will be used for in vivo tacking of radiolabeled T cells in mouse brain. This system is based on the use of the intensified electron multiplying charge-coupled device (I-EMCCD) camera that offers the combination of an excellent intrinsic spatial resolution, a good signal-to-noise ratio, a large active area and a reasonable detection efficiency over an energy range between 27–140 keV. In this study, the dual-head SPEM system was evaluated using both resolution phantoms and a mouse with locally injected T cells labeled with I-125. It was demonstrated that for a relatively concentrated source object, the current dual-head SPEM system is capable of visualizing the tiny amount of radioactivity (∼12 nCi) carried by a very small number (