Siemens SMARTZOOM collimators employ the magnifying properties of a cone-beam collimator near the center of the field of view and eliminating truncation at the edges of the field of view similar to a parallel-hole collimator. The unique position and shape of each hole in the collimator, also referred to as a vector map, is measured in the factory at Siemens and stored with the collimator to be used during reconstruction. The result is an increase of up to four-times more sensitivity.
IQ•SPECT positions the heart in the center of the collimator field of view and positions the detectors at a 28 cm radius for the cardio-centric orbit. IQ•SPECT uses the flexibility of the Symbia™ gantry to position each detector at an optimal distance to maximize sensitivity gain and minimize feelings of claustrophobia.
The advanced IQ•SPECT reconstruction method is a proprietary implementation of a conjugate-gradient iterative reconstruction algorithm. The algorithm is optimized to accurately reflect the measured geometry of the SMARTZOOM collimators and the cardio-centric orbit of the detectors. A 3D measurement of gantry deflection allows correction of gantry motion based image distortions. Measurements of hole size, shape, and pointing direction for all 48,000 holes in the SMARTZOOM collimator ensure accurate image reconstruction.