SPECT radioactive pharmaceuticals and their clinical uses
| Tracers | Half-life | Target | MOA | Clinical use | References |
|---|---|---|---|---|---|
| 123I-IMP | 13.3 h | rCBF | Lipophilic tracer crosses BBB, binds to brain tissue in proportion to perfusion | Diagnosis of dementia, including AD | [139, 140] |
| 99mTc-HMPAO | 6.7 h | rCBF | Lipophilic tracer crosses the BBB, gets trapped in neurons, and reflects cerebral perfusion | Diagnosis and evaluation of AD, monitoring disease progression, and treatment response | [141] |
| 99mTc-ECD | 6 h | rCBF | Bind to brain tissue, reflecting rCBF | Evaluating cerebral perfusion, distinguishing AD from other dementias | [142–144] |
| 123I-AV-45 | 110 min | Aβ plaques | Binds to Aβ aggregates in the brain | Used to assess the presence of Aβ in AD | [68] |
| 123I-PiB | 13.3 h | Aβ plaques, tau protein | Amyloid-binding, PET-SPECT hybrid | Diagnosis of AD, differentiating AD from other dementias | [125, 145] |
| Benzathine (99mTc-Tc-BZ) | 6.3 h | Aβ plaques, BBB disruption | BBB disruption, SPECT-imaging of brain function and perfusion | Diagnosis of AD, monitoring disease progression, and treatment response | [146] |
123I-IMP: iodine-123 labeled 2-iodo-3-(N,N-dimethylamino) propylamine; 99mTc-HMPAO: technetium-99m hexamethylpropyleneamine oxime; 99mTc-ECD: technetium-99m ethyl cysteinate dimer; 123I-AV-45: iodine-123 amyvid (florbetapir); 123I-PiB: iodine-123 pittsburgh compound B; rCBF: regional cerebral blood flow; Aβ: amyloid beta; BBB: blood brain barrier; SPECT: single photon emission computed tomography; PET: positron emission tomography; AD: Alzheimer’s disease; MOA: mechanism of action