Photonics as a Science covers many aspects of light, from UV to IR spectrum. Laser is a great part of the Science of photonics. The Science is mixing particles with waves, making it a bit of quantum science.

If we look at killing or weakening tumor cells there are treatments used that do use light science. Laser, LED and full spectrum light are incorporated in SPDT [sono-photo-dynamic-therapy] more info is found here: http://tinyurl.com/mbt2jyx
Here the use of varied light penetrate to the tumor where an activate, administered earlier by the patient is activated within all cancer cells. The cells typically die when light hits them. Tumors shrink using this method. There is also the use of Near Infrared Light that is used directly on a tumor site that penetrated the area, at prescribed intervals the patient exposes the area to the NIR light, the light penetrates and heats deep into the infected area whereby the tumor is heated. Cancer cells do not survive well in heat; thus they weaken and die off Both of these methods are well tolerated and have no side effects.

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