Absorption wavelength molec targeted o nanoparticles

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: §༊ Beer’s law – not best, but simplest • Decaying exponential term – decays as get into tissue • Mu effective – analogous to absorption coefficient Absorption vs Scattering o Anything that has color – generates photoacoustic contrast §༊ Red because absorbing all light except red light à༎ transmits to eyes §༊ Photoacoustic imaging – interested in this, it’s generating our contrast o Milk – so strongly scattering (white – all different wavelengths scattered) Equation o It’s the pressure at your absorber, still has to travel back to your transducer (more acoustic scattering this time) Optical absorption o Generating photo. Contrast o Very wavelength- dependent o Oxygenative vs deoxygenated o Can use diff. spectrum to differentiate between nanoparticles which have distinct absorption spectrum from blood in the area o Tissue optical window – do between 700- 1200 nm – best penetration depth, minimum tissue absorption o Can tune nanoparticles to absorb here Plasmon Resonance o 3 charges on surface – oscillate up and down with electric field §༊ Oscillation results in heat generation (light à༎ heat) §༊ Efficient process (absorb fiver orders of magnitude more than clinical dye) • • • • • • • • Metallic Nanoparticle… o Lots of different types o By changing shape, change where they absorb o Get shifted to higher wavelength because of aspect ratio §༊ Longer nanorod à༎ corresponds to longer resonant wavelength à༎ inc. absorption wavelength Molec. Targeted o Nanoparticles inc. to 100 deg C within short period of time à༎ melt them o Thus, silica coat them (allows them to transmit heat to tissue very efficiently) §༊ Burn tissue? Orthotropic Pancreatic Cancer o Targeted to EGFR (associated with many types of cancer and often over- expressed), w...
View Full Document

This note was uploaded on 05/15/2012 for the course BME 251 taught by Professor Staff during the Spring '08 term at University of Texas.

Ask a homework question - tutors are online