Photoablation Technology

Photoablation is the use of ultraviolet laser light to break down and remove matter.

The Spectranetics CVX-300® Excimer Laser System generates 308nm laser energy by electrically charging two gases, Xenon and Chloride (XeCl). The ultraviolet light is focused on multiple lesion morphologies consisting of calcified and fibrotic plaque, thrombus and neointimal hyperplasia in the coronary and peripheral vasculature. It is also able to free cardiac pacemaker and ICD leads from binding scar tissue.

The laser energy is transmitted along flexible fiber-optic strands encased in catheters and sheaths, which are passed through arteries and veins. The ultraviolet light energy is focused on the cardiovascular lesion or tissue requiring treatment. This process is called photoablation.

How does photoablation work?

Sub-cellular sized material is easily absorbed by the bloodstream to be carried out of the body, minimizing the risk of distal embolization. Unique to excimer lasers, the ultraviolet energy is greater than the molecular bonds of the tissue. Billions of bonds fracture per pulse. The timing of the pulse is in nanoseconds, amazingly fast, considering light travels 2.4 meters in this time. This is 2.4 million times faster than the blink of an eye.

The laser light pulse targets the tissue for 125 billionths of a second. This pulsing aids in keeping the target cool while the energy dissipates between pulses.

The laser light expands to a penetration depth of 50 microns, allowing the catheter or sheath to provide focused ablation on the tissue it contacts.

The laser energy gently breaks down the tissue into particles, most of which are smaller than a red blood cell.

Unique to excimer lasers, the UV photon energy is greater than the molecular bonds of the tissue. Billions of bonds fracture per pulse. The timing of the pulse is in nanoseconds, amazingly fast, considering light travels 2.4 meters in this time. This is 2.4 million times faster than the blink of an eye.

Absorption creates molecular vibration in molecules through heating of intracellular water. The water vaporizes, rupturing cells. This process creates gaseous byproducts, which produce a vapor bubble. All of this occurs within 100 millionths of a second, thereby limiting heat build-up in surrounding tissue.

The fast expansion and implosion of the vapor bubble produces cavitation and pressure effects that further break down tissue and assist in sweeping ablated debris from the tip of the catheter.

Debris byproducts consist of water, hydrocarbons (gases) and small particles. Notably absent are oxidative byproducts, which implies that the molecules in the tissue do not burn. More than 91 percent of the particles are less than 10 microns in diameter, the same size as red blood cells.

Secondary cavitation bubbles can form after the implosion of the first vapor bubble, further assisting in tissue ablation and removal of debris. The entire process (per pulse) is over in approximately 500 millionths of a second, and the next pulse arrives 24 milliseconds later.

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