Combined Prototype (PI)
In the first part, we combined all the developed optical technologies in a shoebox-sized volume.
The setup is a combination of smart feedback systems (Optical coherence tomography (OCT), Laser-induced breakdown spectroscopy (LIBS), Opto-acoustics (OA)) and a 3-µm ablation laser into a non-moving volume of approximately shoebox size. The ablation, OCT, and LIBS lasers share a common optical path in free space, which is a step towards miniaturization of the setup. These smart feedback systems are integrated together to provide real-time information about tissue type, depth profile, and temperature during cutting.
The feedback systems are employed as safety mechanisms to prevent damage to surrounding tissue during laser osteotomy and prevent carbonization of the bone. When LIBS and/or OA detect that laser is cutting a soft tissue outside of a bone, the ablation automatically stops. Temperature of the sample is monitored by a thermal camera and the OCT system. When temperature increases above the predetermined threshold for carbonization, the water cooling is applied. Water irrigation and pressurized air are applied externally. Here, water irrigation enables to keep the surface temperature of the bone samples below the predetermined threshold for carbonization while pressurized air adjusts the amount of water on the surface by blowing the excessive amount.
The setup is covered by a plexi-glass enclosure to protect the optics from dust, water and tissue particles generated by ablation. The lens closest to the sample is protected by a sapphire window and an air-flow shutter. The setup can make functional cuts (line, zig-zag, custom shape) on a target tissue including bone, bone marrow, muscle and skin. Movement for making cuts is realized by a 3D-stage moving the sample.