recent progress in medical laser technologies ____________________________ 醫 療 雷 射 技 術...

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  • Slide 1
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  • Recent Progress in Medical Laser Technologies ____________________________ 3-2008 J.T. Lin, Ph.D Chairman New Vision, Inc. ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
  • Slide 3
  • Definitions LASER Light LASER Light Amplification by Amplification by Stimulated Emission of Stimulated Emission of Radiation ( ) Radiation ( )-------------------------------------------------------------------------------- ( ) vs ( ) ( ) vs ( )---------------------------------------------------------------------------------------- (Photon) vs. (Wave) (Photon) vs. (Wave) ----------------------------------------------- ----------------------------------------------- Diode vs. LED Diode vs. LED (laser) . (light) (laser) . (light)
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  • Historical 1900 (Max Planck) quantum mechanics 1900 (Max Planck) quantum mechanics 1917 (Einstein) A & B Coefficients 1917 (Einstein) A & B Coefficients 1954 (Townes)... MASER (microwave) 1954 (Townes)... MASER (microwave) 1960 (Maiman) Ruby laser 1960 (Maiman) Ruby laser 1961 (Javan, Johnson) . HeNe, Nd:YAG 1961 (Javan, Johnson) . HeNe, Nd:YAG 1962 (Bennett).. Argon laser 1962 (Bennett).. Argon laser 1964 (Patel) . CO2 laser 1964 (Patel) . CO2 laser The laser-patent war /Gordon Gould (1997). The laser-patent war /Gordon Gould (1997). 1983.. (UV-193 on organic tissue IBM Patent, ) 1983.. (UV-193 on organic tissue IBM Patent, ) 1990 . PRK (vision correction, VisX patent) 1990 . PRK (vision correction, VisX patent) 1992 . LASIK (Scanning) ( Lins patent) 1992 . LASIK (Scanning) ( Lins patent) 1998 . Presbyopia-I (Lins patent) 1998 . Presbyopia-I (Lins patent) 2008 . Presbyopia-II, 3um didoe-laser (Lin) 2008 . Presbyopia-II, 3um didoe-laser (Lin)
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  • Overall Laser Applications , , , , , , , , , , , , , ,
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  • (1) (low divergence) , , (2) (high intensity): focused spot size (micron ~ 0.001 mm) focused spot size (micron ~ 0.001 mm) (3) Pure-spectrum (narrow band-width): spectroscope, chemistry.. spectroscope, chemistry.. (4) Tunable spectrum (via non-linear processes) , , (pulse width) , , (pulse width) (5) (high Coherence) SPECIAL Features of LASER:
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  • Non-medical applications Military Military - laser range-finder (1064, 1554 nm) - laser range-finder (1064, 1554 nm) - laser beam-weapon (STAR War) - laser beam-weapon (STAR War) Car industry: Car industry: - speeding, counter-speeding - speeding, counter-speeding - collision-free - collision-free - auto-parking - auto-parking - overhead screen, GPS - overhead screen, GPS - auto-driven - auto-driven
  • Slide 8
  • Bio-medical Bio-Medical Photonics Energy beams : Laser, LED, RF, non-coherent- light, Ultrasound Optical materials Fibers & beam delivery Optical diagnosis, spectroscope Electronic System integration Software & hardware Bio-imaging, Bio-sensor Photo-therapy (PDT) Photo-biology Surgical, coagulation Drug delivery, tracking, characterization Nano-medicine, bio-materials, bio-chem Tissue Engineering/welding Bionic human (artificial organs) NVI Photon + Electronics Biology + Medicine + +
  • Slide 9
  • to be an Innovator ( to be an Innovator ( ) Rumsfield (2006) Know known Un-know known Un-know un-known Know un-known Innovation VS. Improving NVI
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  • ( Pioneer ) VS. ( Follower ) (innovator) ! Know un-known =
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  • ( ) ITRI Projects ( ) (1) ( ) (1) ( ) - - - - (2) , , ( ) (2) , , ( ) (3) (3) (4) 2 ~ 3 (4) 2 ~ 3 . . (5) , , , . (5) , , , .
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  • Examples of innovation-IMPACT Only < 1% patents has major financial impacts !!! Only < 1% patents has major financial impacts !!! (the METHODS patents) (the METHODS patents) IBM (1983 US patent): IBM (1983 US patent): UV laser (193 nm, ArF) for all organic tissue ablation UV laser (193 nm, ArF) for all organic tissue ablation licensed to LaserSight for >$30M licensed to LaserSight for >$30M Steve Troke (Columbia Univ.) Steve Troke (Columbia Univ.) 1986 US PatArF for PRK/LASIK 1986 US PatArF for PRK/LASIK value : >$2.0 B value : >$2.0 B JT Lin (1991, 2000, 2004, 2006 US pat) JT Lin (1991, 2000, 2004, 2006 US pat) scanning-laser for Lasik scanning-laser for Lasik value > $500M value > $500M Shue Lai (1993) Shue Lai (1993) eye-tracking device, value >$200M eye-tracking device, value >$200M JT Lin (1998).. JT Lin (1998).. laser for presbyopia value > $200M (???) laser for presbyopia value > $200M (???)
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  • Medical products development Idea, concept, theory Lab test, R&D Clinical (Animal, human) (in Vitro, in Vivo) System Integration & Commercialization Search, re-search Defining parameters Proto-type (1-2 years) Phase-I (Safety) Phase-II (Efficacy) Phase-III (Commercial) (1-8 years) FDA approval (510-K or PMA) (patents, improving) Lin-7-2007 NVI
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  • Bio-Physics Laser-tissue interaction Mechanisms: (Absorption, reflection, scattering) Mechanisms: (Absorption, reflection, scattering) 1) Thermal 1) Thermal 2) non-thermal 2) non-thermal 3) combined effects 3) combined effects (Coagulation-ablation, cutting-incision) (Coagulation-ablation, cutting-incision) Key parameters: Key parameters: Wavelength, Pulse width (Tp), Wavelength, Pulse width (Tp), Energy (E), Intensity (I), Power (P), fluency (F) Energy (E), Intensity (I), Power (P), fluency (F) Absorption coefficient (A), Reflection/scattering loss Absorption coefficient (A), Reflection/scattering loss concept: F = E/ laser spot-size concept: F = E/ laser spot-size I= E/ pulse-width I= E/ pulse-width
  • Slide 15
  • Thermal vs. Non-thermal (1) Thermal: ( most cosmetic lasers): (1) Thermal: ( most cosmetic lasers): low-power, low intensity, long-pulse low-power, low intensity, long-pulse weak-absorption (A), weak-absorption (A), CW visible lasers, LED (400-700 nm) CW visible lasers, LED (400-700 nm) Diode (1.3-2.2 um) Diode (1.3-2.2 um) Ho:YAG (2.1 um), CO/2(10.6 um) Ho:YAG (2.1 um), CO/2(10.6 um) (2) Non-thermal (Lasik, kidney-stone, dental/hard-tissue) (2) Non-thermal (Lasik, kidney-stone, dental/hard-tissue) Short-pulse, high peak-power, Short-pulse, high peak-power, Strong absorption (A>100 cm-1) Strong absorption (A>100 cm-1) (in water, tissue, melanin, protein, etc) (in water, tissue, melanin, protein, etc) short-pulsed (ps - fs) laser (independent to wavelength) short-pulsed (ps - fs) laser (independent to wavelength) Er:YAG (2.94 um), Excimer-laser (193, 248, 308 nm) Er:YAG (2.94 um), Excimer-laser (193, 248, 308 nm)
  • Slide 16
  • Absorption (blood, skin) wavelength (um) melanin HbO 2 420 580 A 0.2 0.5 1.0 1.2
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  • Absorption in Water/Tissue 0 1.0 2.0 3.0 10 (microns) Absorption (A) 1.45 1.93 2.94 CO2-laser
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  • Penetration-depth (d=1/A) vs. wavelength UV VISIBLE Near-IR Mid-IR (0.2-0.4) (04.-0.7) (0.8- 2.1) (2.7-3.2) um (0.05-0.5) mm (0.5-2.0) (2.0-6.0) (0.2-0.5) 0.05 mm Water 3 absorption peaks: 1.45, 1.93, 2.94 um
  • Slide 19
  • Laser Ablation Theory (1) Beers law: I(z) = I(0) Exp [-Az] I(z) = I(0) Exp [-Az] (2) Ablation depth (H) is given by H = (1/A) ln (F/F*) H = (1/A) ln (F/F*) where F*= threshold laser fluence where F*= threshold laser fluence for ablation to occur. for ablation to occur. optimal A* given by dH/dA = 0 optimal A* given by dH/dA = 0 A*=2.718 (F*/F) A*=2.718 (F*/F) (3) Lins law (2005, for focused laser) I = B I(0) Exp(-Az) I = B I(0) Exp(-Az) B=focusing factor for optimal depth. B=focusing factor for optimal depth. 0 F* F Depth (H) 0 A* A Depth (H)
  • Slide 20
  • Laser heating theory Laser produced tissue temperature via heat conduction equation Laser produced tissue temperature via heat conduction equation dT/dz = k (d 2 T/dz 2 ) dT/dz = k (d 2 T/dz 2 ) where k=temperature conductivity where k=temperature conductivity Laplace transform or the Green function method to obtain Laplace transform or the Green function method to obtain T(z,t) = Integrate { S G dz dt } T(z,t) = Integrate { S G dz dt } S is the heat source and G is the Green function given by S is the heat source and G is the Green function given by G = C exp [ -(z-z0)^2 / 4k(t t0) ] G = C exp [ -(z-z0)^2 / 4k(t t0) ] Thermal penetration depth Thermal penetration depth d* = square root of (4kt) d* = square root of (4kt) = 0.75 square root [laser pulse width] = 0.75 square root [laser pulse width] for d (in um)m and t (in usec). for d (in um)m and t (in usec). Example: Example: for 1 usec laser, the heat conduction distance is about 0.75 um. for 1 usec laser, the heat conduction distance is about 0.75 um. The one-micron rule: ( t*=1.0 usec) The one-micron rule: ( t*=1.0 usec) short pulsed laser for non-thermal process. short pulsed laser for non-thermal process. example: fiber laser (f.s.) example: fiber laser (f.s.) time Temp.
  • Slide 21
  • System design consideration 1. Hemoglobin (blood) 2. Melanei (skin-color) 3. Water (Tissue) 4. Others (protein etc) (2) Hard tissue (bones, teeth) shock-wave plasma-assisted Wrinkle-removalHair-removal PDT Non-invasive (invasive) (1) For soft-tissue
  • Slide 22
  • Major medical procedures 1. 1. 2. 2. 3. 3. 4. , 4. , 5. 5.
  • Slide 23
  • (Prostate) Technology: endoscope + laser + fiber Technology: endoscope + laser + fiber Laserscope, Inc. (acq. by AM

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