A relatively little known fact about carbon nanotubes is that the single walled variety are fluorescent (or photoluminescent) when they are excited. This is because when high enough frequency light is shone upon them a negative electron and a positive hole (lack of electron) are both promoted, relax and then recombine emitting a photon that is just outside the infrared spectrum. This can’t happen in a metal or truly conducting material because any hole will be instantly filled with an electron resulting in just classical energy band emission.
This has a use in medical physics as infrared light can’t pass very far through the body but is attenuated very differently by different materials over short distances. This makes it like a mini X-Ray that can detect individual layers of skin rather than bones and muscle. The problem is that although exciting the nanotubes can be done through a focus lamp or LED, detecting the infrared emission requires very sensitive, very expensive detectors that one would have to be very specialised to use. The other problem is getting the nanotubes to the location that they’re needed and distributing them so that the proper effect is achieved. If it does work however the benefits would be massive: a 3D, computer generated model of a piece of tissue allowing for micro operations and directed treatement to be done for maximum effect.