Scanning Micromirror Platform Based on MEMS Technology for Medical Application

This topical review discusses recent development and trends on scanning micromirrors for biomedical applications. This also includes a biomedical micro robot for precise manipulations in a limited volume. The characteristics of medical scanning micromirror are explained in general with the fundamental of microelectromechanical systems (MEMS) for fabrication processes. Along with the explanations of mechanism and design, the principle of actuation are provided for general readers. In this review, several testing methodology and examples are described based on many types of actuators, such as, electrothermal actuators, electrostatic actuators, electromagnetic actuators, pneumatic actuators, and shape memory alloy. Moreover, this review provides description of the key fabrication processes and common materials in order to be a basic guideline for selecting micro-actuators. With recent developments on scanning micromirrors, performances of biomedical application are enhanced for higher resolution, high accuracy, and high dexterity. With further developments on integrations and control schemes, MEMS-based scanning micromirrors would be able to achieve a better performance for medical applications due to small size, ease in microfabrication, mass production, high scanning speed, low power consumption, mechanical stable, and integration compatibility.

[1]  Thomas E. Milner,et al.  Fast 3D in vivo swept-source optical coherence tomography using a two-axis MEMS scanning micromirror , 2008 .

[2]  Chengkuo Lee,et al.  Characterization of piezoelectric PZT beam actuators for driving 2D scanning micromirrors , 2010 .

[3]  Ajay Agarwal,et al.  A novel electrostatic microactuator for large deflections in MEMS applications , 2006 .

[4]  Siavash Yazdanfar,et al.  Scanning mirror for optical coherence tomography using an electrostatic MEMS actuator , 2002, Proceedings IEEE International Symposium on Biomedical Imaging.

[5]  Jiaru Chu,et al.  Design, fabrication and characterization of a bulk-PZT-actuated MEMS deformable mirror , 2007 .

[6]  吴亚明,et al.  High-Speed and Large-Scale Electromagnetically Actuated Resonant MEMS Optical Scanner , 2007 .

[7]  X.M. Zhang,et al.  Real Pivot Mechanism of Rotary Comb-Drive Actuators for MEMS Continuously Tunable Lasers , 2007, TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference.

[8]  Huikai Xie,et al.  A curved multimorph based electrothermal micromirror with large scan range and low drive voltage , 2011 .

[9]  Woonggyu Jung,et al.  A Three Dimensional Real-Time MEMS Based Optical Biopsy System for In-Vivo Clinical Imaging , 2007, TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference.

[10]  Yu Sun,et al.  Nanonewton force-controlled manipulation of biological cells using a monolithic MEMS microgripper with two-axis force feedback , 2008 .

[11]  Luiz Otávio Saraiva Ferreira,et al.  A novel Si micromachined moving-coil induction actuated mm-sized resonant scanner , 2006 .

[12]  Carlos H. Mastrangelo,et al.  Single-crystal silicon micromirror array with polysilicon flexures , 2005 .

[13]  Huikai Xie,et al.  A multi-degree-of-freedom micromirror utilizing inverted-series-connected bimorph actuators , 2006 .

[14]  Brett E Bouma,et al.  Two-axis magnetically-driven MEMS scanning catheter for endoscopic high-speed optical coherence tomography. , 2007, Optics express.

[15]  Svetlana Tatic-Lucic,et al.  A multi-axis electrothermal micromirror for a miniaturized OCT system , 2011 .

[16]  W. Piyawattanametha,et al.  Two-Dimensional MEMS Scanner for Dual-Axes Confocal Microscopy , 2007, Journal of Microelectromechanical Systems.

[17]  C. Mastrangelo,et al.  Two-axis single-crystal silicon micromirror arrays , 2004, Journal of Microelectromechanical Systems.

[18]  Dongqing Yin,et al.  Micro torsion mirror actuated by compound electrostatic driving structure , 2007 .

[19]  Jin Cheng,et al.  Feasibility study of a smart motion generator utilizing electromagnetic microactuator arrays , 2006 .

[20]  Koji Fujimoto,et al.  Microelectromechanical flexure PZT actuated optical scanner: static and resonance behavior , 2005 .

[21]  Chengkuo Lee,et al.  A 2-D MEMS scanning mirror based on dynamic mixed mode excitation of a piezoelectric PZT thin film S-shaped actuator. , 2011, Optics express.

[22]  Huikai Xie,et al.  Miniature endoscopic optical coherence tomography probe employing a two-axis microelectromechanical scanning mirror with through-silicon vias. , 2011, Journal of biomedical optics.

[23]  Takayuki Fujita,et al.  Dual-axis MEMS mirror for large deflection-angle using SU-8 soft torsion beam , 2005 .

[24]  Gary K. Fedder,et al.  A CMOS-MEMS mirror with curled-hinge comb drives , 2003 .

[25]  John D. Grade,et al.  Advanced, vibration-resistant, comb-drive actuators for use in a tunable laser source , 2004 .

[26]  Alyssa B. Apsel,et al.  Fabrication and electromechanical characterization of silicon on insulator based electrostatic micro-scanners , 2005 .

[27]  Walter M. Duncan,et al.  Emerging digital micromirror device (DMD) applications , 2003, SPIE MOEMS-MEMS.

[28]  Chengkuo Lee,et al.  Novel piezoelectric actuation mechanism for a gimbal-less mirror in 2D raster scanning applications , 2011 .

[29]  K. Najafi,et al.  A 3-DOF piezoelectric micro vibratory stage based on bulk-PZT/silicon crab-leg suspensions , 2013, 2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS).

[30]  Huikai Xie,et al.  A SCS CMOS micromirror for optical coherence tomographic imaging , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[31]  Chi-Yuan Lee,et al.  A MEMS micromirror fabricated using CMOS post-process , 2005 .

[32]  R. Muller,et al.  Magnetically actuated, addressable microstructures , 1997 .

[33]  Chengkuo Lee,et al.  MOEMS variable optical attenuators using rotary comb drive actuators , 2006, IEEE Photonics Technology Letters.

[34]  Todd R. Christenson,et al.  Deep X-Ray Lithography Based Fabrication of Rare-Earth Based Permanent Magnets and their Applications to Microactuators , 1999 .

[35]  Huikai Xie,et al.  A single-crystal silicon micromirror for large bi-directional 2D scanning applications , 2006 .

[36]  Youngjoo Yee,et al.  Fabrication and characterization of a PZT actuated micromirror with two-axis rotational motion for free space optics , 2001, Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090).

[37]  Baykal Sarioglu,et al.  Design and fabrication of two-axis micromachined steel scanners , 2009 .

[38]  Ai Qun Liu,et al.  Advanced fiber optical switches using deep RIE (DRIE) fabrication , 2003 .

[39]  Malgorzata Kujawinska,et al.  A two directional electrostatic comb-drive X–Y micro-stage for MOEMS applications , 2010 .

[40]  Slava Krylov,et al.  Large angle SOI tilting actuator with integrated motion transformer and amplifier , 2008 .

[41]  Renaud Jourdain,et al.  Pre-stressed piezoelectric bimorph micro-actuators based on machined 40 µm PZT thick films: batch scale fabrication and integration with MEMS , 2010 .

[42]  J. F. Miner,et al.  Flexible fabrication of large pixel count piston-tip-tilt mirror arrays for fast spatial light modulators , 2007 .

[43]  Gerhard Lammel,et al.  Two-dimensional thermally actuated optical microprojector , 2000 .

[44]  Kwang-Seok Yun,et al.  A low-voltage two-axis electromagnetically actuated micromirror with bulk silicon mirror plates and torsion bars , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[45]  Luke P. Lee,et al.  A novel microfabrication of a self-aligned vertical comb drive on a single SOI wafer for optical MEMS applications , 2005 .

[46]  Hiroyuki Fujita,et al.  Fabrication and operation of polyimide bimorph actuators for a ciliary motion system , 1993 .

[47]  Hans Zappe,et al.  Thermo-pneumatically actuated, membrane-based micro-mirror devices , 2006 .

[48]  D. P. Potasek,et al.  Characterizing fruit fly flight behavior using a microforce sensor with a new comb-drive configuration , 2005, Journal of Microelectromechanical Systems.

[49]  Cheng-Tang Pan.  Silicon-based coupling platform for optical fiber switching in free space , 2004 .

[50]  Gary K. Fedder,et al.  Endoscopic optical coherence tomography with new MEMS mirror , 2003 .

[51]  A. Werber,et al.  Tunable, membrane-based, pneumatic micro-mirrors , 2005, IEEE/LEOS International Conference on Optical MEMS and Their Applications Conference, 2005..

[52]  Huikai Xie,et al.  Endoscopic optical coherence tomography with a modified microelectromechanical systems mirror for detection of bladder cancers. , 2003, Applied optics.

[53]  K. Kurabayashi,et al.  A single-layer PDMS-on-silicon hybrid microactuator with multi-axis out-of-plane motion capabilities-Part i: design and analysis , 2005, Journal of Microelectromechanical Systems.

[54]  Liwei Lin,et al.  Bi-directional electrothermal electromagnetic actuators , 2007 .

[55]  J. Fujimoto,et al.  In vivo endoscopic optical biopsy with optical coherence tomography. , 1997, Science.

[56]  G. Fedder,et al.  Vertical comb-finger capacitive actuation and sensing for CMOS-MEMS , 2002 .

[57]  J. E. Bower,et al.  Monolithic fringe-field-activated crystalline silicon tilting-mirror devices , 2003 .

[58]  C.S. Premachandran,et al.  Design, Fabrication, and Assembly of an Optical Biosensor Probe Package for OCT (Optical Coherence Tomography) Application , 2007, IEEE Transactions on Advanced Packaging.

[59]  Oliver Paul,et al.  Thermally actuated CMOS micromirrors , 1995 .

[60]  Chit Yaw Fu,et al.  MEMS micromirror integrated endoscopic probe for optical coherence tomography bioimaging , 2011 .

[61]  Hiroshi Goto,et al.  The 2-dimensional micro scanner integrated with PZT thin film actuator , 1997, Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97).

[62]  R. Ghodssi,et al.  Design, Fabrication, and Characterization of a Rotary Micromotor Supported on Microball Bearings , 2008, Journal of Microelectromechanical Systems.

[63]  M.C. Wu,et al.  Surface-micromachined 2-D optical scanners with high-performance single-crystalline silicon micromirrors , 2001, IEEE Photonics Technology Letters.

[64]  Brian C Wilson,et al.  Design, Fabrication, and Characteristics of a MEMS Micromirror With Sidewall Electrodes , 2010, Journal of Microelectromechanical Systems.

[65]  Sun Jian,et al.  Fabrication and Characterization of a Lead Zirconate Titanate Micro Energy Harvester Based on Eutectic Bonding , 2011 .

[66]  Y Watanabe,et al.  A 2-axis optical scanner driven nonresonantly by electromagnetic force for OCT imaging , 2006 .

[67]  Min Hu,et al.  Micromirror structure based on TiNi shape memory thin films , 2005, SPIE Micro + Nano Materials, Devices, and Applications.

[68]  Hanhua Feng,et al.  Microfabricated endoscopic probe integrated MEMS micromirror for optical coherence tomography bioimaging , 2010, 2010 Annual International Conference of the IEEE Engineering in Medicine and Biology.

[69]  J. M. Kim,et al.  SOI-based fabrication processes of the scanning mirror having vertical comb fingers , 2002 .

[70]  K. Najafi,et al.  A 6-DOF piezoelectric micro vibratory stage based on multi-axis distributed-electrode excitation of PZT/Si unimorph T-beams , 2013, 2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII).

[71]  Harald Schenk,et al.  Fabrication and characterization of a dynamically flat high resolution micro-scanner , 2008 .

[72]  S. O. R. Moheimani,et al.  Characterization of a 2-DoF MEMS nanopositioner with integrated electrothermal actuation and sensing , 2012, 2012 IEEE Sensors.

[73]  D. Briand,et al.  Epitaxial piezoelectric MEMS on silicon , 2010 .

[74]  Chengkuo Lee,et al.  A MEMS rotary comb mechanism for harvesting the kinetic energy of planar vibrations , 2010 .

[75]  M.R.J. Gibbs,et al.  Magnetic materials for MEMS applications , 2004 .

[76]  G. Fedder,et al.  Endoscopic optical coherence tomography based on a microelectromechanical mirror. , 2001, Optics letters.

[77]  David P. Arnold,et al.  Micro Magnetic Induction Machines for Portable Power Applications , 2003 .

[78]  Chengkuo Lee,et al.  Design and fabrication of epitaxial silicon micromirror devices , 2004 .

[79]  G. Fedder,et al.  A two-axis electrothermal micromirror for endoscopic optical coherence tomography , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[80]  Nanguang Chen,et al.  A two axes scanning SOI MEMS micromirror for endoscopic bioimaging , 2008 .

[81]  C. Corcoran,et al.  Electromagnetically actuated mirror arrays for use in 3-D optical switching applications , 2004, Journal of Microelectromechanical Systems.

[82]  Gary K. Fedder,et al.  Endoscopic optical coherence tomographic imaging with a CMOS-MEMS micromirror $ , 2003 .

[83]  Guo-Qiang Lo,et al.  A Two-Wafer Approach for Integration of Optical MEMS and Photonics on Silicon Substrate , 2010, IEEE Photonics Technology Letters.

[84]  Siyuan He,et al.  Repulsive-force out-of-plane large stroke translation micro electrostatic actuator , 2011 .

[85]  P. Sarro,et al.  In-package MEMS-based thermal actuators for micro-assembly , 2006 .

[86]  Yong-Kweon Kim,et al.  Silicon scanning mirror of two DOF with compensation current routing , 2004 .

[87]  P. Ferreira,et al.  A SOI-MEMS-based 3-DOF planar parallel-kinematics nanopositioning stage , 2008 .

[88]  Yixian Qian,et al.  Design of a MEMS micromirror actuated by electrostatic repulsive force , 2012 .

[89]  Rajesh Rajamani,et al.  A novel dual-axis electrostatic microactuation system for micromanipulation , 2002, IEEE/RSJ International Conference on Intelligent Robots and Systems.

[90]  Joseph A. Izatt,et al.  Piezoelectric scanning mirrors for endoscopic optical coherence tomography , 2009 .

[91]  Wibool Piyawattanametha,et al.  Two-axis MEMS Scanning Catheter for Ultrahigh Resolution Three-dimensional and En Face Imaging. , 2007, Optics express.

[92]  Nanguang Chen,et al.  Design and development of a 3D scanning MEMS OCT probe using a novel SiOB package assembly , 2008 .

[93]  Huikai Xie,et al.  A large vertical displacement electrothermal bimorph microactuator with very small lateral shift , 2008 .

[94]  S Yazdanfar,et al.  Electrostatic micromachine scanning mirror for optical coherence tomography. , 2003, Optics letters.

[95]  Andreas Kenda,et al.  Large stroke MOEMS actuators for optical path length modulation in miniaturized FTIR spectrometers , 2009, Defense + Commercial Sensing.

[96]  Yong Qing Fu,et al.  TiNi-based thin films in MEMS applications: a review , 2004 .

[97]  M. Sinclair,et al.  A high frequency resonant scanner using thermal actuation , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[98]  D. McCormick,et al.  Gimbal-less monolithic silicon actuators for tip-tilt-piston micromirror applications , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[99]  Dannis Michel Brouwer,et al.  Design and modeling of a six DOFs MEMS-based precision manipulator , 2010 .

[100]  Rajesh Rajamani,et al.  A high-aspect-ratio two-axis electrostatic microactuator with extended travel range , 2002 .

[101]  Huikai Xie,et al.  3D in vivo optical coherence tomography based on a low-voltage, large-scan-range 2D MEMS mirror. , 2010, Optics express.

[102]  M. Wu,et al.  A scanning micromirror with angular comb drive actuation , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[103]  Andrew A. Goldenberg,et al.  Micromachined 2-D scanner for 3-D optical coherence tomography , 2005 .

[104]  Hanhua Feng,et al.  A 3mm endoscopic probe with integrated MEMS micromirror for optical coherence tomography bioimaging , 2010 .

[105]  Jun Zhang,et al.  Three-dimensional optical coherence tomography employing a 2-axis microelectromechanical scanning mirror , 2005, IEEE Journal of Selected Topics in Quantum Electronics.

[106]  Emily J. McDowell,et al.  Methods and application areas of endoscopic optical coherence tomography. , 2006, Journal of biomedical optics.

[107]  Weileun Fang,et al.  A Novel Coilless Scanning Mirror Using Eddy Current Lorentz Force and Magnetostatic Force , 2007, Journal of Microelectromechanical Systems.

[108]  Alex Dommann,et al.  Biaxial scanning mirror activated by bimorph structures for medical applications , 1992 .

[109]  Liudi Jiang,et al.  SiC cantilever resonators with electrothermal actuation , 2006 .

[110]  Kui Yao,et al.  A piezoelectric micro-actuator with three dimensional structure and its micro-fabrication , 2005, The 13th International Conference on Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05..

[111]  George G. Adams,et al.  Design, modeling, fabrication and testing of a high aspect ratio electrostatic torsional MEMS micromirror , 2006 .

[112]  Baoping Wang,et al.  A tip-tilt-piston micromirror with a double S-shaped unimorph piezoelectric actuator , 2013 .

[113]  N. Andreff,et al.  SQUIPABOT: A Mesoscale Parallel Robot for a Laser Phonosurgery , 2014, 2014 International Symposium on Optomechatronic Technologies.

[114]  Michael S.-C. Lu,et al.  A large-displacement CMOS micromachined thermal actuator with comb electrodes for capacitive sensing , 2007 .

[115]  J. Yeh,et al.  Large rotation actuated by in-plane rotary comb-drives with serpentine spring suspension , 2005 .

[116]  K. Kurabayashi,et al.  A single-layer PDMS-on-silicon hybrid microactuator with multi-axis out-of-plane motion capabilities-part II: fabrication and characterization , 2005, Journal of Microelectromechanical Systems.

[117]  Jay A. Hammer,et al.  A design methodology for a bulk-micromachined two-dimensional electrostatic torsion micromirror , 2003 .

[118]  Ching-Liang Dai,et al.  Manufacture of Micromirror Arrays Using a CMOS-MEMS Technique , 2009, Sensors.

[119]  Jun Zhang,et al.  Three-dimensional endoscopic optical coherence tomography by use of a two-axis microelectromechanical scanning mirror , 2006 .

[120]  Yingtian Pan,et al.  MEMS-based Endoscopic Optical Coherence Tomography , 2004 .

[121]  Huikai Xie,et al.  A thermal bimorph micromirror with large bi-directional and vertical actuation , 2005 .

[122]  M.C. Wu,et al.  Surface- and bulk- micromachined two-dimensional scanner driven by angular vertical comb actuators , 2005, Journal of Microelectromechanical Systems.

[123]  Xuming Zhang,et al.  A review of MEMS external-cavity tunable lasers , 2006 .

[124]  Huikai Xie,et al.  A piezoelectric unimorph actuator based tip-tilt-piston micromirror with high fill factor and small tilt and lateral shift , 2011 .

[125]  Weileun Fang,et al.  A molded surface-micromachining and bulk etching release (MOSBE) fabrication platform on (1 1 1) Si for MOEMS , 2006 .

[126]  K. Pister,et al.  MONOLITHIC SILICON MICROMIRRORS WITH LARGE SCANNING ANGLE , 2001 .

[127]  Zhihua Feng,et al.  Miniature orthogonal optical scanning mirror excited by torsional piezoelectric fiber actuator , 2011 .

[128]  Kam Y. Lau,et al.  A FLAT HIGH-FREQUENCY SCANNING MICROMIRROR , 2000 .

[129]  Zhongping Chen,et al.  360/spl deg/ rotating micro mirror for transmitting and sensing optical coherence tomography signals , 2004, Proceedings of IEEE Sensors, 2004..

[130]  Elena Villa,et al.  The high potential of shape memory alloys in developing miniature mechanical devices: A review on shape memory alloy mini-actuators , 2010 .

[131]  H. Toshiyoshi,et al.  Optically Modulated MEMS scanning endoscope , 2006, IEEE Photonics Technology Letters.

[132]  Jason M. Zara,et al.  Optical scanner using a MEMS actuator , 2002 .

[133]  Xianke Lin,et al.  Iop Publishing Journal of Micromechanics and Microengineering Large Displacement Vertical Translational Actuator Based on Piezoelectric Thin Films , 2022 .

[134]  Masayoshi Esashi,et al.  Minimally invasive diagnostics and treatment using micro/nano machining , 2006, Minimally invasive therapy & allied technologies : MITAT : official journal of the Society for Minimally Invasive Therapy.

[135]  Hans Zappe,et al.  Fiber optic tunable probe for endoscopic optical coherence tomography , 2008 .

[136]  Xinyu Liu,et al.  A MEMS Stage for 3-Axis Nanopositioning , 2007, 2007 IEEE International Conference on Automation Science and Engineering.

[137]  Huikai Xie,et al.  An Electrothermal Tip–Tilt–Piston Micromirror Based on Folded Dual S-Shaped Bimorphs , 2009, Journal of Microelectromechanical Systems.

[138]  Jun Yao,et al.  A MEMS micromirror driven by electrostatic force , 2010 .

[139]  Kazuhiro Hane,et al.  Design, fabrication and vacuum operation characteristics of two-dimensional comb-drive micro-scanner , 2011 .

[140]  G. Stemme,et al.  Arrays of monocrystalline silicon micromirrors fabricated using CMOS compatible transfer bonding , 2003, The Sixteenth Annual International Conference on Micro Electro Mechanical Systems, 2003. MEMS-03 Kyoto. IEEE.

[141]  Chengkuo Lee,et al.  Investigation of piezoelectric driven MEMS mirrors based on single and double S-shaped PZT actuator for 2-D scanning applications , 2012 .

[142]  Chee Yee Kwok,et al.  Monolithically integrated out-of-plane micro-mirror , 2012 .

[143]  Tae-Sun Lim,et al.  Electrostatic MEMS variable optical attenuator with rotating folded micromirror , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[144]  Lulu Zhang,et al.  2D micro scanner actuated by sol-gel derived double layered PZT , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[145]  K. Pister,et al.  Scanning micromirrors fabricated by an SOI/SOI wafer-bonding process , 2006, Journal of Microelectromechanical Systems.

[146]  Huikai Xie,et al.  MEMS mirrors based on curved concentric electrothermal actuators with very small lateral shift and tilt , 2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference.

[147]  H. Funabashi,et al.  A Z-axis differential capacitive SOI accelerometer with vertical comb electrodes , 2004, 17th IEEE International Conference on Micro Electro Mechanical Systems. Maastricht MEMS 2004 Technical Digest.

[148]  Y. Shacham-Diamand,et al.  Large angle SOI tilting actuator with integrated motion transformer and amplifier , 2008, 2008 IEEE 21st International Conference on Micro Electro Mechanical Systems.

[149]  P. Renaud,et al.  Thermally actuated optical microscanner with large angle and low consumption , 1999 .

[150]  Hans Zappe,et al.  Fabrication of bulk-Si micromirrors with an integrated tilt sensing mechanism , 2006 .

[151]  G. Dogangil,et al.  A review of medical robotics for minimally invasive soft tissue surgery , 2010, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[152]  U Seitz,et al.  In vivo endoscopic optical coherence tomography of the human gastrointestinal tract--toward optical biopsy. , 2000, Endoscopy.