Comparison of radioligands for imaging of 5-HTT in humans
| Properties | [123I]β-CIT SPECT | [11C](+)McN5652 PET | [11C]DASB PET | [123I]ADAM SPECT |
|---|---|---|---|---|
| Selectivity | Nonselective, near 1:1 affinity for 5-HTT to DAT (22), (23) | Likely selective 10:1 to 100:1 affinity for 5-HTT over NET (24), (25) | Highly selective 1000:1 affinity for 5-HTT over NET or DAT* (26), (27) | Highly selective 1000:1 affinity for 5-HTT over NET or DAT (28), (29) |
| Displaceability of specific binding | Incomplete (30), (31) | In most, but not all, reports (19), (32), (33) | Highly displaceable (26), (27), (34), (35) | Highly displaceable (28), (29), (36) |
| Reversibility† | Good (37), (38) | Not adequate to adequate, depending on region‡ (18), (19), (39) | Adequate in midbrain, good to very good in other regions (20), (21), (40) | Adequate in midbrain (36), (41) |
| Brain uptake | Adequate (37), (38) | Good (19), (39) | Very good (20), (21), (40) | Adequate (36), (41) |
| Specific binding to free and nonspecific binding ratio† | Good | Not adequate in most regions, adequate in thalamus (39), (42) | Adequate to very good‡ (20), (21) | Not adequate in most regions; adequate in midbrain (36), (41) |
| Reliability of 5-HTT BP† | Not measured | Modest (32) | Very good to excellent (34), (43) | Most regions reasonable (41) |
| 5-HTT BP measurability in multiple regions | Brainstem only (37), (38) | Measurable in thalamus, (39) not measurable in cortex (19) | Yes (20), (21) | Measurable in midbrain; unclear for other regions (36), (41) |