The invention provides a device and method for illuminating a body surface. A light source is optically coupled to the proximal end of a light guide and a light scatterer is optically coupled to the distal end of the light guide. The device includes a deployment mechanism that is configured to bring the light scatterer from a small caliber configuration in which the light scatterer is delivered to the body surface to a large caliber configuration in which the light scatterer irradiates the body surface. The invention may be used, for example, irradiate the periadventitial surface of an aneurysmal blood vessel.
