Subject and 11C-PBR28 Imaging Parameters
| Parameter | Nonsmokers (n = 20) | Smokers (n = 20) |
| Age (y) | 31.0 ± 12.2 | 34.6 ± 10.2 |
| Sex | 13 M; 7 F | 15 M; 5 F |
| rs6971 genotype | 11 HAB; 9 MAB | 15 HAB; 5 MAB |
| Cigarettes/d | NA | 15 ± 8 |
| Fagerström Test for Nicotine Dependence | NA | 6 ± 2 |
| Urge to Smoke Questionnaire | ||
| Intent | NA | 10 ± 4 |
| Relief | NA | 11 ± 5 |
| Beck Depression Inventory | 1 ± 2 | 3 ± 3 |
| Injected dose (MBq) | 575 ± 174 | 505 ± 188 |
| Injected mass (μg) | 2.3 ± 1.9 | 0.79 ± 0.60 |
| Plasma free fraction (%) | 2.3 ± 0.8 | 2.6 ± 0.9 |
HAB = high-affinity binder; MAB = medium-affinity binder; NA = not applicable.
Qualitative data are numbers; continuous data are mean ± SD.