Development of Minimally Invasive Medical Tools Using Laser Processing on Cylindrical Substrates

This paper reports micro-fabrication techniques using laser processing on cylindrical substrates for the realization of high-performance multifunctional minimally invasive medical tools of small size. A spring-shaped shape memory alloy (SMA) micro-coil with a square cross-section has been fabricated by spiral cutting of a Ti-Ni SMA tube with a femtosecond laser. A small-diameter active bending catheter actuated by a hydraulic suction mechanism for intravascular minimally invasive diagnostics and therapy has also been developed. The catheter is made of Ti-Ni superelastic alloy (SEA), which is processed by laser micromachining, and a silicone rubber tube that covers the outside of the SEA tube. The active catheter is effective for insertion into branches of blood vessels that diverge at acute angles where it is difficult to proceed. Multilayer metallization and patterning have been performed on glass tubes with 2- and 3-mm external diameters using maskless lithography techniques with a laser exposure system. Using the laser soldering technique, integrated circuit parts have been mounted on a multilayer circuit patterned on a glass tube. These fabrication techniques will be effective for the realization of high-performance multifunctional catheters, endoscopic tools, and implanted small capsules. (c) 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 65-74, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21030