Current imaging modalities of interest in pulmonary drug research and discovery
| Technique | Spatial Resolution and Time Scale | Application | Main Characteristics | |
|---|---|---|---|---|
| Small Rodents | Humans | |||
| CT | 50–100 μm; seconds to minutes | ∼600 μm; < 1 min | Anatomical, functional | Ionizing radiation; poor soft tissue contrast |
| Scintigraphy | No | ∼20 mm; | Functional | Planar information |
| SPECT (low-energy γ-rays) | ≤1 mm; ∼20 min | ∼10 mm; 10–30 min | Functional | Ionizing radiation; radioisotopes have longer half-lives than those used in PET; sensitivity 10 to 100 times smaller than PET |
| PET (high-energy γ-rays) | 1–2 mm; ∼20 min | ∼4 mm; ∼20 s | Metabolic, functional, molecular | Ionizing radiation; high sensitivity (picomolar concentrations); cyclotron needed |
| MRI | 80–140 μm; seconds to hours | 1.5 mm; seconds to minutes | Anatomical, functional, molecular | High spatial resolution and soft tissue contrast; low sensitivity |
| NIRF optical imaging | 1–3 mm; seconds to minutes | No | Molecular | High sensitivity (nanomolar concentrations); maximal penetration depth <10 cm |