Nanotechnology in Medical Imaging
Positron Emission Topography Scanning
- Provides functional information - not structural
- Blood flow, glucose metabolism, and O2 use
- Increased tissue penetration - radiotrackers
- carriers for radiotracer molecules
- Multimodal imaging
- large surface area
- Good for diagnostic and research
Benefits
Computed Tomography Scanning
Bodily Interactions
- Works with all other imaging devices
- Cost = purchase of contrast materials
- Hospital already pays for
- Able to better view in contrast
- View of tumors and other tissues more exact
- Provides new updates for all of the imaging modules
- Typically recognized as foreign -> immune response
- Mononuclear phagocyte system
- Complement system (blood proteins)
- Balance : circulation time + signal strength
- Coating agents : time + stability
- Concern = aggregation
- Hydrophilic and neutral surfaces
Bibliography
- X-ray based imaging -> cross sectional images
- Now = iodine/gadolinium based contrast
- nonspecific, short circulation, catheterization, renal toxicity, poor in larger
- Bismuth sulphide, iodinated, + gold
- 2 step synthesis + 5x increase in absorption : -controlling + modifying shape/surface
- Iodine -> nanostructures : longer circulation + increased concentration
- 2-5x absorption + prolonged circulation time + rapid renal clearance + lower radiation
- http://www.omicsonline.org/nanotechnology-and-diagnostic-imaging-new-advances-in-contrast-agent-technology-2157-7439.1000115.php?aid=2095
- http://circ.ahajournals.org/content/107/8/1092.full
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844987/
What is diagnostic imaging?
Technologies that look into the body to diagnose pathologies
- contrast agents: sensitivity
Nanotechnologies - sensitivity, bio-compatibility, and bio-distribution
CT with Nanotechnology
Magnetic Resonance Imaging
- High temporal and spatial resolution
- Safe and non-invasive
- Relaxation time to radiofrequency pulse measured - provides contrast
- Contrast agents enhance visibility:
- Now = Gadolinium
- SPION
- Contrast enhancement
- Retain zero net magnetization
- Minimize iron loading
Targeting
- Most often publicized promises of nanotechnology
- Passive targeting
- Selective accumulation : tumors
- Active targeting
- Specific biomarker : internalization and intracellular accumulation