Abstract—The Detector Group at the Thomas Jefferson
National Accelerator Facility (Jefferson Lab) and the Biology,
Physics, and Applied Sciences Departments at the College of
William and Mary are collaborating on the development of a
miniature dual modality SPECT-CT system for mouse imaging.
The detector heads of the SPECT sub-system are designed to be
capable of imaging the gamma- and X-ray emissions (28–35 keV)
of the radioactive isotope iodine-125 (I-125). Two different sets
of I-125 imaging detectors are configured on a gantry that has
an open-barrel type design. One set of detector heads is based on
the 1-in square Hamamatsu R5900-M64 position sensitive photomultiplier
tube coupled to crystal scintillator arrays. The other
detector heads configured on the gantry are two 5-in diameter
Hamamatsu R3292-based compact gamma cameras. The X-ray
radiographic projections are obtained using a LIXI Inc. model
LF-85-503-OS X-ray imaging system that has an active area of
5.5 cm in diameter. The open-barrel shaped gantry facilitates
the positioning of various mini gamma-ray imaging detectors
and the X-ray system. The data acquisition and gantry control
is interfaced through a Macintosh G3 workstation. Preliminary
SPECT reconstruction results using the R5900 based detector are
presente