Photothermal Therapy

Overview
Photothermal Therapy (PTT) is an extremely new therapeutic use of electromagnetic radiation (most often in the form of visible light) that is proposed to treat various medical conditions, including cancer. The basic model for its use is derived in part from Photodynamic Therapy, whereas a photosensitizer is excited with specific band light. This activation brings the sensitizer to an excited state where it then releases vibrational energy (heat). The heat is the actual method of therapy that interacts with whatever agent has been targeted (cancer cells, for example). The increase in temperature can cause numerous biological interactions that will be the result of the therapy (protein denaturization, cancer cell necrosis or apoptosis, etc).

Photothermal Therapy vs Photodynamic Therapy
Being in close relation to Photodynamic Therapy, the two are often compared as potential methods to treat cancer, among other applications. Photothermal therapy is listed as being advantageous in that it does not require oxygen to interact with the target cells or tissues. Current studies also show that Photothermal therapy is able to use longer wavelegth light (which is less energetic and therefore less harmful to other cells and tissues). Challenges of Photothermal therapy mostly lay it its novelty, as it is much less studied, however some research has indicated problems with aggregation of the photosensitizers, local shock waves, hyperthermic effects, and otherwise little phototoxicity. As this is a brand new field of therapy, many of the side effects and complications, as well as the potential applications of Photothermal Therapy, are unknown.