Photoacoustic pressure wave generation for intravascular calcification disruption

A photoacoustic catheter for treating a calcified lesion, the photoacoustic catheter comprising:

• an elongate shaft extending from a proximal region to a distal region, the elongate shaft including a light guide that includes an optical fiber, the light guide being in optical communication with a light source that includes a laser, the light guide including a side surface and a diverter, the diverter directing light in the light guide toward the side surface, the diverter including one of a reflecting element and a refracting element;
• and
• a photoacoustic transducer disposed within the distal region of the elongate shaft, the photoacoustic transducer being in optical communication with the light guide, the photoacoustic transducer being adapted to selectively impart acoustic pressure waves upon the calcified lesion to induce fractures in the calcified lesion, the photoacoustic transducer including a layer of light-absorbing material and a separate layer of thermal expansion material, the layers of material being individually applied to the light guide;
• wherein the light-absorbing material is selected from the group consisting of nanoparticles, carbon nanotubes, candle soot, candle soot nanoparticles, carbon black, a nanotube array, multiwall carbon nanotubes, and light absorbing dye;
• wherein the thermal expansion material is selected from the group consisting of polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), polyimide, polyisobutylene (PIB), PIB polyurethane, polyurethanes, styrene isoprene butadiene, ethylene propylene polyacrylic, ethylene acrylic, fluorosilicone, polybutadiene, polyisoprene, and thermoplastic elastomers;
• wherein the layer of light-absorbing material and the layer of thermal expansion material form a composite film around the light guide.