In some embodiments, an apparatus includes a catheter having a catheter body, a light emitter disposed at a distal end of the catheter body, and a fluid conduit coupleable to a source of fluid. The fluid conduit configured to discharge fluid from the source via the conduit and out a distal end of the catheter body. A spacing member is disposed at the distal end of the catheter body and can be moved between a collapsed configuration and an expanded configuration. In the expanded configuration, the spacing member is disposed about the light emitter. The spacing member is at least partially transmissive and/or transflective of light emitted from the light emitter. The apparatus configured to be inserted at least partially into a body lumen, to discharge fluid into the body lumen, and to emit light from the light emitter to illuminate an interior wall of the body lumen.