Impact of NaI(Tl) Detector Thickness on Image Quality
| Parameter | CoDe5NC | CoDe8NC | P* | 95% CI |
|---|---|---|---|---|
| All tumor lesions (n = 54) | ||||
| T/NT ratio | 4.2 ± 3.5 | 6.3 ± 5.2 | <0.0005 | 1.3, 3.0 |
| T/Bg ratio | 4.9 ± 3.9 | 6.4 ± 5 | <0.0005 | 0.8, 2.3 |
| Assessment of lesions according to location | ||||
| Above diaphragm (n = 31) | ||||
| T/NT ratio | 4.5 ± 4 | 7.1 ± 5.7 | <0.0005 | 1.3, 3.9 |
| T/Bg ratio | 5.25 ± 4.6 | 7.5 ± 5.7 | <0.0005 | 1.1, 3.4 |
| Below diaphragm (n = 23) | ||||
| T/NT ratio | 3.7 ± 2.6 | 5.2 ± 4.3 | <0.001 | 0.6, 2.4 |
| T/Bg ratio | 4.3 ± 2.7 | 4.8 ± 3.3 | NS | −0.3, 1.4 |
| Assessment of lesion of different sizes† | ||||
| Lesions <7.2 mL (n = 14) | ||||
| T/NT ratio | 3.6 ± 2.8 | 6.2 ± 4.7 | <0.001 | 1.2, 4.0 |
| T/Bg ratio | 4 ± 3 | 6.6 ± 4.3 | <0.0005 | 1.4, 3.6 |
| Lesions 7.2–12.5 mL (n = 13) | ||||
| T/NT ratio | 4.2 ± 3.7 | 6 ± 2.7 | <0.01 | 0.3, 3.4 |
| T/Bg ratio | 4.6 ± 3 | 6.5 ± 3.3 | <0.03 | −0.02, 3.9 |
| Lesions 12.5–17.5 mL (n = 14) | ||||
| T/NT ratio | 4.4 ± 4 | 7 ± 7.7 | <0.01 | 0.4, 4.9 |
| T/Bg ratio | 5 ± 3.8 | 6.4 ± 6.4 | <0.05 | −0.3, 3.2 |
| Lesions >17.5 mL (n = 13) | ||||
| T/NT ratio | 4.5 ± 3.5 | 6 ± 4.9 | NS | −0.5, 3.3 |
| T/Bg ratio | 6 ± 5.4 | 6 ± 5.7 | NS | −1.3, 1.5 |
↵* P < 0.05 was considered significant. NS = not significant.
↵† Parameters evaluated: T/NT ratio and T/Bg ratio. Lesion size was measured by functional volumes. Descriptive statistics were used to define 4 subgroup limits.
Image sets compared were CoDe5NC, 5/8-in. NaI(Tl) crystals without attention correction; and CoDe8NC, 1-in. NaI(Tl) crystals without attention correction.