(a) Magnified view of the striatal phantom with fillable striata (http://www.rsdphantoms.com/nm_striatal.htm). The volume of each compartment is 4.8 ml (right caudate), 4.9 ml (left caudate), 5.8 ml (right putamen), 6.0 ml (left putamen,) and 1260 ml (background). (b) The phantom was positioned on the D-SPECT facing the center of the detector array. (c) A prescan of the phantom on the D-SPECT. The prescan was acquired using a motor file designed for a cardiac imaging. A scan pattern using the motor file focused on the dashed circle that was presumed to enclose the heart. A new circular ROI of 6 cm radius (solid line) was drawn to assign a new scan pattern to maximize the counts from the region. In order to obtain the clearest possible view of the striata, the right and left putamen were filled with Tc-99m while other compartments contained only air.
An example of scan pattern. The angular increment was 0.6° when the detector was collecting data from the fine sampling region. In the coarse sampling region, it varied from 0.8° to 2.6°.
Projections on the nine D-SPECT detector blocks acquired for 5 s for (a) background filled with 4.2 μCi/cc, (b) left striata filled with 22.6 μCi/cc, and (c) right striata filled with 30.2 μCi/cc. (White dots indicate the locations of disabled crystals.) One 5-s projection view on the Symbia (d) background filled with 4 μCi/cc, (e) left striata filled with 30 μCi/cc, and (f) right striata filled with 44 μCi/cc.
SNR for estimation of activity concentration in the right striata as a function of total counts detected on the conventional system, for two values of BR.
The CRB on precision of estimates of specific-to-nonspecific BR as a function of total counts detected on the conventional system for BR = 5.
SNR for measuring asymmetry index, as a function of asymmetry ratio, for two values of BR.
Specifications and scan parameters for the conventional and dedicated systems.
The signal-to-noise ratio for detecting a small change in binding ratio with the baseline BR = 5.0.
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