Performance of HRRT versus Conventional 3D BGO*
| Feature |
HRRT |
Conventional BGO PET |
| No. Detector Heads |
8/octagonal array |
3 rings
|
| Detector blocks/head |
117 (13 x 9) |
4/bucket, 12 buckets/ring |
| Crystals/block |
64 |
64 |
| Crystal Type |
Lutetium Oxyorthosilicate (LSO) (with LYSO) |
Bisthmuth Germanate (BGO) |
| Crystal size (mm) |
Two layers of LSO (2.4 x 2.4 x 10) and LYSO |
6.75 x 6.75 x 30 |
| Total Number of Crystals |
59,904 x 2 layers |
9,216 |
| Total No. of Photomultiplier Tubes |
1120 |
576 |
| Planes in reconstructed image |
207 |
47 |
| Slice Thickness (mm) |
1.21875 |
3.37 |
| Matrix |
256 x 256 |
128 x 128 |
| Axial Field of View |
24 cm |
16 cm |
| Transverse Field of View |
31.2 cm |
56 cm |
| Transmission Imaging |
Cs-137 |
Ge-68 |
| Sensitivity-Total Trues |
1,700,000 cps/microCi/ml |
120,000 cps/microCi/ml |
| Peak Noise Equivalent Count (NEC) Rate |
200,000 cps/microCi/ml |
100,000 cps/microCi/ml |
| Scatter Fraction |
35% |
35% |
| Transaxial Spatial Resolution FWHM-Center |
2.4 mm |
5.8mm |
| Transaxial Spatial Resolution FWHM-10 mm from center |
2.8 mm |
6.2 mm |
| Axial Spatial Resolution at Center |
2.4 mm |
4.2 mm |
| Count Rate (Dead Time) Saturation |
14,000,000 total cps |
750,000 cps |
| Scintillation decay time |
40 ns |
300 ns |
| Coincidence Window |
6 ns |
12 ns |
*ECAT 921 used for comparison.