MIRSURG project develops table-top laser for minimally invasive brain surgery

31 May 2012

The EU funded MIRSURG project has developed a table-top solid-state laser system that can cut brain tissue with unprecedented precision. The project involves partners from seven European countries.

 The new laser emits short pulses exactly at 6.45 microns with a repetition rate of 100-200 Hz which ensures the targeted average power of over 1 Watt.

The greatly reduced collateral damage at this wavelength is due to the combined absorption of water and resonant laser heating of non-aqueous components (proteins). The penetration depth at this wavelength is on the order of several microns, which is comparable to the cell size, and is therefore close to the optimum value, not achievable by any other state-of-the-art lasers.

"There were so far no compact and reliable solid-state lasers emitting at the desired mid-infrared wavelength," said Dr Valentin Petrov from Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI), coordinator of the consortium.

The project was launched in 2008 with the objective to close up the gap for diode-pumped solid-state lasers in the mid-infrared spectral range around 6.45 microns. At the MIRSURG final meeting in spring 2012 in Saint-Louis, France, the project team presented a rather compact all-solid-state prototype that fits on a table-top. The desired optical wavelength of 6.45 microns is generated by frequency conversion. A laser beam with a wavelength near 2 microns is converted to the mid-infrared by the use of nonlinear optical crystals.

The challenge for the researchers was to achieve simultaneously all the most appropriate but still technically feasible parameters for soft tissue ablation. They managed to combine the desired wavelength with high single pulse energy of more than 5 millijoules, short pulse duration of about 30 nanoseconds and good focusing capability. The repetition rate, long term stability and reliability of the entire laser system seem ideally suited for practical surgical applications.

The project partners of MIRSURG intend to further optimize the new table-top laser, assess its tissue ablation capabilities and, possibly within a follow-up project, demonstrate real solid-state laser surgery at 6.45 microns. "I hope that in the near future such a laser could become a practical surgical tool in every specialized operating room," said Petrov.

Further information

The MIRSURG website: www.mirsurg.eu


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