Fabrication and characterization of cylindrical light diffusers comprised of shape memory polymer

Abstract

Cylindrical light diffusing devices are used in various interstitial and endoluminal biomedical applications including thermal laser therapies^{1, 2} and photodynamic therapy. ^{3, 4, 5, 6, 7} Our group has also used them for in vitro photothermal actuation of endovascular prototype devices including embolic foams to fill aneurysms^{8, 9} and self-expanding stents.¹⁰ The diffuser is generally located at the end of a flexible optical fiber and is guided to the target through a needle, catheter, or endoscope. The required optical and mechanical characteristics of the light-diffusing device are application-dependent. Optical characteristics including the light emission profile and the power-handling capability, together with the tissue absorption and scattering properties, govern the amount and distribution of light delivered to the target tissue volume. Mechanical characteristics including diffuser length, diameter, and flexibility determine where in the body the device can be delivered.