Abstract
We report the current status of the less-invasive laser treatment of atherosclerosis with a 5.75-μm
Wavelength. This selective treatment exploits characteristic absorption by biomolecules in the midinfrared
range. With pulsed lasers, we achieved the selective removal of atherosclerotic plaque at 5.75
μm, which is the absorption peak of cholesteryl esters in atherosclerotic plaque. The absorption is
derived from the C = O stretching vibration mode. This result demonstrated the effectiveness of the midinfrared
region for advanced less-invasive treatments. However, for clinical applications, problems
remain, such as the equipment size, ablation efficiency, and the thermal effect. Therefore, further
progress of mid-infrared light sources is required.
