Flash vaporization surgical systems

Abstract

A laser can produce pulses of light energy to eject a volume of the tissue, and the energy can be delivered to a treatment site through a waveguide, such as a fiber optic waveguide. The incident laser energy can be absorbed within a volume of the target tissue with a tissue penetration depth and pulse direction such that the propagation of the energy from the tissue volume is inhibited and such that the target tissue within the volume reaches the spinodal threshold of decomposition and ejects the volume, for example without substantial damage to tissue adjacent the ejected volume.

1 . An apparatus to treat tissue, the apparatus comprising:
 a laser system to generate a laser pulses having a wavelength between 1400 and 1520 nm or between 1860 and 2500 nm, having between 1 and 40 milliJoules per pulse, and having a pulse duration less than 200 nsec; and   a beam delivery device coupled to the laser system, to deliver said pulses from the laser to spots on the tissue; whereby an interaction volume defined by the area of the spot and the penetration depth (1/e) for the pulse in water, the interaction volume having a ratio of depth to width from 2:1 to 1:6, wherein the volumetric power density delivered to each spot is greater than 10 10  W/cm 3  and the spot size of the spots on the tissue is 50 to 200 micro-meters.   
     
     
         2 . The apparatus of  claim 1 , wherein a pulse repetition rate is from single shot to 2 kHz. 
     
     
         3 . The apparatus of  claim 1 , wherein the wavelength is between 1880 and 2080 nm or between 2340 and 2500 nm, and the pulses have between 1 and 30 milliJoules per pulse. 
     
     
         4 . The apparatus of  claim 1 , wherein the pulse duration is less than 100 nsec. 
     
     
         5 . The apparatus of  claim 1 , wherein the laser pulses deliver a volumetric power density to the interaction volume that induces spinodal decomposition of water in the tissue and kinetic energy confined within the interaction volume to eject tissue. 
     
     
         6 . The apparatus of  claim 1 , wherein:
 the laser system is configured so that at least one of wavelength, pulse repetition rate, pulse duration and energy per pulse is controllable;   and including   a controller coupled to the laser system, including a user input to select operating modes for the laser, including at least a first operating mode in which the laser has a wavelength a wavelength between 1400 and 1520 nm or between 1860 and 2500 nm, having and an energy per pulse between 0.5 and 40 milliJoules per pulse to irradiate a volume of tissue at the spots such that the volume of the tissue is ejected with spinodal decomposition, the laser pulses having a duration less than 200 nsec and short enough to inhibit stress and thermal energy propagation from the volume, and at least a second operating mode in which tissue coagulation results without ejection by spinodal decomposition, wherein laser pulses in the second operating mode have a pulse duration more than 100 micro seconds.   
     
     
         7 . The apparatus of  claim 6 , wherein the controller is operable during an exposure so that said first operating mode and said second operating mode are intermixed during an exposure. 
     
     
         8 . The apparatus of  claim 6 , in which the laser pulses in the first operating mode have a first wavelength, and the laser pulses in the second operating mode have a second wavelength. 
     
     
         9 . The apparatus of  claim 6 , wherein the beam delivery device includes a silica waveguide having a core diameter in a range of 10 to 300 micro-meters. 
     
     
         10 . The apparatus of  claim 6 , wherein a pulse repetition rate in the first operating mode is from single shot to 2 kHz. 
     
     
         11 . The apparatus of  claim 6 , wherein in the first operating mode, the wavelength is between 1880 and 2080 nm or between 2340 and 2500 nm, and the pulses have between 1 and 10 milliJoules per pulse. 
     
     
         12 . The apparatus of  claim 6 , wherein in the first operating mode, the pulse duration is less than 100 nsec. 
     
     
         13 . The apparatus of  claim 6 , wherein the laser system includes a gain medium comprising a thulium doped host. 
     
     
         14 . The apparatus of  claim 6 , wherein the beam delivery device comprises a plurality of waveguides, arranged to deliver a plurality of pulses in a pattern of spots on the tissue. 
     
     
         15 . The apparatus of  claim 6 , wherein the beam delivery device comprises a plurality of waveguides, arranged to deliver a plurality of pulses in parallel to a single spot. 
     
     
         16 . An apparatus to treat tissue, the apparatus comprising:
 a laser system to generate a laser pulses having a wavelength between 1400 and 1520 nm or between 1860 and 2500 nm, having between 0.5 and 40 milliJoules per pulse, in which at least one of wavelength, pulse repetition rate, pulse duration and energy per pulse is controllable; and   an imaging system to provide direct visualization images;   a waveguide coupled to the laser, to deliver pulses from the laser to spots on tissue; and   a controller coupled to the laser system, including a user input to enable an operating mode in which the laser has a wavelength and an energy per pulse to irradiate a volume of tissue at the spots such that the volume of the tissue is ejected with spinodal decomposition, the laser pulses having a duration short enough to inhibit stress and thermal energy propagation from the volume.   
     
     
         17 . The apparatus of  claim 16 , wherein the controller includes a user input to select operating modes for the laser, including at least one additional operating mode in which tissue coagulation results without ejection by spinodal decomposition. 
     
     
         18 . The apparatus of  claim 16 , including a flexible endoscope, and said waveguide includes a silica fiber waveguide disposed in the endoscope. 
     
     
         19 . The apparatus of  claim 16 , wherein the waveguide includes a silica optical fiber having a core diameter in a range of 50 to 200 microns. 
     
     
         20 . The apparatus of  claim 16 , wherein the waveguide delivers a spot to tissue with a diameter in a range of 50 to 200 microns. 
     
     
         21 . The apparatus of  claim 16 , wherein a pulse repetition rate is from single shot to 2 KHz. 
     
     
         22 . The apparatus of  claim 16 , wherein the wavelength is between 1880 and 2080 nm or between 2340 and 2500 nm, and the pulses have between 1 and 10 milliJoules per pulse, and a pulse duration less than 200 nsec. 
     
     
         23 . The apparatus of  claim 16 , wherein the laser system includes a gain medium comprising a thulium doped host. 
     
     
         24 . The apparatus of  claim 16 , including an insertion device which comprises a flexible endoscope including said waveguide, and said waveguide comprises a silica optical fiber having a core diameter between 50 um and 200 um. 
     
     
         25 . The apparatus of  claim 16 , including
 an insertion device, including said waveguide, said waveguide including a fiber optic to deliver pulses from the laser to spots on tissue, with a diameter in the range of 50 to 200 um.   
     
     
         26 . The apparatus of  claim 16 , wherein the pulse duration is less than 100 ns. 
     
     
         27 . The apparatus of  claim 16 , wherein the laser pulses deliver a volumetric power density to interaction volume that induces spinodal decomposition of water in the tissue and kinetic energy confined within the interaction volume to eject tissue. 
     
     
         28 . The apparatus of  claim 27 , wherein the volumetric power density delivered to each spot is greater than 10 10  W/cm 3 . 
     
     
         30 . The apparatus of  claim 16 , the laser configured to generate pulses having a pulse duration less than 200 nsec.