Physical performance of the Siemens MultiSPECT 3 gamma camera.

We evaluated physical performance of the new Siemens MultiSPECT 3 gamma camera. The camera is a triple-headed, large detector system dedicated to multislice single photon emission tomographic (SPET) imaging over all the human body. A triangular aperture up to 60 cm in diameter and a patient couch with low gamma-ray attenuation allow all patients to be studied without exception. The patient is easily, quickly and reproducibly positioned. Collimator change is rapidly and semiautomatically performed. Camera tuning, calibration, acquisition and processing are controlled by a MacIntosh Quadra 950 computer. The ICON software is easy to use (a mouse driven system) and the operator does not necessarily need to go through the manuals. The software includes useful reporting and imaging utilities but the version tested by us (vol. 3.0) also has several limitations such as no gated or dynamic SPET, no list-mode acquisition and no body outline attenuation correction. The planar sensitivity using high-resolution collimators (HR) is 380 cps MBq-1 for 99Tcm with a symmetric energy window of 15%. The radial SPET resolution is 8.5 mm full-width half-maximum (FWHM) in scatter with a rotational radius of 12.6 cm (corresponding to the radius of a brain scan) and a tangential resolution of 7.1 mm. The quality of the daily bone, brain and heart scans is superior when compared to those of a conventional single-headed gamma camera. The system allows fast and accurate SPET imaging both for clinical routine practice and for research.