Parameters Commonly Used for SPECT Recording and Reconstruction
| Parameter | Discovery NM 530c | DSPECT | IQ⋅SPECT | Conventional SPECT |
| Recording | ||||
| Collimator | Multipinhole | Wide-angle parallel hole | Astigmatic | LEHR or parallel hole |
| Energy window | 140 keV ± 10% | 140 keV ± 10% | 140 keV ± 7.5% | 140 keV ± 7.5% |
| Number of projections | 19 | 120 (×9 blocks) | 17 (×2 heads) | 16 (×2 heads) |
| Detector angle between consecutive projections | None (fixed detector) | 0.4°–7°* | 6° | 3° |
| Reconstruction | ||||
| Method | Iterative 3D | Iterative 3D | Iterative 3D | Iterative 3D |
| Number of iterations | 60 | 7 | 10 | 8 |
| Number of subsets | 1 | 32 | 3 | 4 |
| Interiteration filter | — | Kernel (0.125) | — | — |
| Final filter | Butterworth (order, 7; cutoff, 0.37 cm−1) | Normalizing filter† | Gaussian (10 mm FWHM) | Gaussian (10 mm FWHM) |
| Pixel size (mm) | 4.0 | 4.92 | 4.8 | 6.6 |
↵* Angles are approximately 0.4° for projections passing through cardiac region (as defined by adjusted region of interest on prescan images) and up to 7° for other projections.
↵† Way in which normalizing filter works is proprietary information of Spectrum Dynamics.
LEHR = low-energy high-resolution; 3D = 3-dimensional; FWHM = full width at half maximum.