서강대학교

초록/요약

For a long time, lasers have been widely used in medical diagnostics and therapeutic applications such as photodynamic and photothermal therapy. Among optical therapeutic methods, photothermal therapy (PTT) has been used as a non-invasive (or miminally-invasive) and selective therapeutic tool, in which light delivered to the target is converted into heat and subsequently causes coagulative necrosis. However, optical scattering in biological media limits light penetration, thus reducing therapeutic efficacy. To overcome the limitation, in the disseration, two methods are proposed to increase therapeutic depth by combining ultrasound and laser while maintaining high target selectivity of PTT. One method increases treatment depth by adding temperatures raised by delivered laser and acoustic energies to the tissue at the same time. This method is called dual thermal therapy (DTT) in the dissertation. Another method is to use the air bubbles temporarily induced by ultrasound in order to increase light penetration into biological tissue. The rationale behind this method is that the air bubbles act as a Mie scattering medium in the pathway of incident light and light is scattered predominantly in the forward direction in a Mie scattering. It is demonstrated that the ultrasound-assisted light penetration increase can be used to surpass the treatment depth limit of PTT. From the results, it is expected that the proposed methods will open a new path to overcome the limitations of current optical imaging and therapeutic technology besides PTT.