Table 2.
Computation time of various projectors (unit in second). F.P.: forward projection, B.P.: backprojection, CPU: 16 threads (Intel Xeon E5530 quad-core processor), GPU: NVIDIA GTX480. The number of events is 54M.
| image size | 150 × 150 × 89 | 200 × 200 × 89 | 300 × 300 × 89 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| transaxial voxel size | 4.0 mm × 4.0 mm | 3.0 mm × 3.0 mm | 2.0 mm × 2.0 mm | ||||||
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| CPU | |||||||||
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| F.P. | B.P. | total | F.P. | B.P. | total | F.P. | B.P. | total | |
| TOF-acc | 196 | 250 | 446 | 311 | 383 | 694 | 625 | 787 | 1412 |
| non-TOF-acc | 151 | 358 | 509 | 258 | 491 | 749 | 514 | 838 | 1352 |
| TOF-Siddon/R- | 11 | 23 | 34 | 14 | 28 | 42 | 24 | 42 | 66 |
| non-TOF-Siddon/R- | 11 | 51 | 62 | 17 | 66 | 83 | 44 | 100 | 144 |
| TOF-Bresenham/R- | 3 | 20 | 23 | 5 | 20 | 25 | 9 | 30 | 39 |
| non-TOF-Bresenham/R- | 4 | 32 | 36 | 8 | 43 | 51 | 24 | 70 | 94 |
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| GPU | |||||||||
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| F.P. | B.P. | total | F.P. | B.P. | total | F.P. | B.P. | total | |
| TOF-Siddon/R- | 2.5 | 5.5 | 8 | 3.6 | 7.3 | 10.9 | 5.9 | 10.9 | 16.8 |
| non-TOF-Siddon/R- | 6.2 | 14 | 20.2 | 8.2 | 18.9 | 27.1 | 12 | 28 | 40 |
| TOF-Bresenham/R- | 1.6 | 3.5 | 5.1 | 2.3 | 4.7 | 7 | 3.8 | 7.2 | 11 |
| non-TOF-Bresenham/R- | 3.9 | 8.9 | 11.8 | 5.6 | 12.2 | 17.8 | 8.8 | 18.9 | 27.7 |