Performance of a dual headed SPECT system modified for coincidence detection

A NIM/CAMAC/Macintosh data acquisition system was developed to collect^±X, ^±Y, and E information from a GE Maxxus SPECT system. A high impedance signal pick-off circuit was used so the data could be collected without disturbing normal operation of the camera. The measured coincidence timing resolution for the system is 8 msec FWHM. The energy resolutions for the detector heads are ~7.5% (using pulse clipping), at 511 keV. The system sensitivity is 70 cps/μCi for a point source centered in the field of view (450-575 keV energy window, 62.6 cm detector spacing). The intrinsic spatial resolution of the detector heads are ~3.7 mm FWHM in the focal plane using linear tomography. Linear tomography image reconstruction and a volume image reconstruction based on the Kinahan-Rogers approach have been implemented. Images of a line source phantom, the Data Spectrum torso phantom, and the 3D Hoffman brain phantom