Photomechanical Drug Pictures

Photoacoustic drug delivery is a technique for delivering drugs to localized areas [Shangguan 1995a, Shangguan 1995b]. Unlike the techniques for enhancing local delivery of molecules using laser-induced shock waves [Zeimer 1988, Flotte 1995], photomechanical drug delivery uses a laser pulse to generate a cavitation bubble in a blood vessel due to the absorption of laser energy by targets (e.g., blood clots) or surrounding liquids (e.g., blood). The cavitation bubble expands and collapses hundreds of microseconds after the laser pulse. The hydrodynamic pressure arising from the expansion and collapse of the cavitation bubble can force the drug into clot or vessel wall. Photomechanical drug delivery can be performed by timing the laser pulses to be coincident with an injected bolus of drug. The delivery system for photomechanical drug delivery could consist of only two elements: an optical fiber or light guide for delivering laser pulses, and catheter tubing for injecting drugs. A fluid-core laser catheter has been used to remove thrombus (blood clot) with a pulsed-dye laser without damaging the vessel wall tissue [Gregory 1990]. Photomechanical drug delivery with such a fluid-core laser catheter may be an alternative method to current techniques for localized drug delivery.

Selected pictures from HanQun Shangguan's thesis.

Close-ups for Frank Blanchard

This is a side view of bubble formation in a 300/cm oil solution confined in a 3mm silicone tube. Single pulses of 33mJ were delivered via a 300µm fiber. The picture was taken at 250µs. 
  • 250.GIF, 241K This is an untouched original of the 250 microsecond picture from the 141k montage shown below.
  • 250a.GIF, 676K A 300dpi cropped version of the above file. This was obtained from 250.gif by croping the image and running it through graphic converter and changing the resolution to 300dpi. It does not have any more information, nor is it much clearer.
  • Figure (3K) Experimental setup for time-resolved flash photography of laser-induced bubble created at the fiber tip in absorbing liquids (water and oil).

    Chapter 3

    Chapter 4

    Chapter 5

    Chapter 7

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