Molecular operation on elastic fibers and cholesterol ester by a free-electron laser

A method has been found to selectively ablate cholesterol esters accumulated in an arteriosclerotic region of a rabbit artery without damaging the blood vessel using a free-electron laser (FEL). A FEL is a pulsed laser source that generates a beam by amplifying the coherent radiation emitted by an electron beam that is traveling through a periodically alternating magnetic field at a relativistic velocity. The characteristics of the FEL include a broadly tunable wavelength and ultra-short pulse width. We have found that FEL irradiation of a rabbit arterial wall for 1 min with a power of 1.5 mW can ablate cholesterol esters without damaging the elastic fibers of the arterial wall. The FEL was tuned to 5.75 micrometer, which is a wavelength that is absorbed by cholesterol ester. This method may be used as a non-invasive surgical procedure for the treatment of arteriosclerotic arteries.