Patent ID: 9622819
Date: 2017-04-18
CPC Classifications: A61B

Claim:
1. A method for tissue removal, comprising: directing laser pulses having a wavelength with an associated optical penetration depth D, an energy per pulse, a fluence φ, a spot area and a pulse duration t generating pressure within the interaction volume of the target tissue which causes ejection of the target tissue within the interaction volume and heating the interaction volume above a spinodal decomposition threshold at the optical penetration depth using the laser pulses, wherein the wavelength is between 1400 and 1520 nm or between 1860 and 2500 nm and the energy per pulse between 0.5 milliJoules and 40 milliJoules, wherein the interaction volume is a function of the optical penetration depth D and the spot area of the laser pulses incident on the target tissue, where the spot area has a minimum width W, and wherein the optical penetration depth D is a function of an absorption coefficient μ where v s speed of sound in the target tissue, and further that the pulse duration t is less than 200 nsec; wherein the energy per pulse of the laser pulses in the heating of the interaction volume heats water within the interaction volume to induce a phase transition by spinodal decomposition within the interaction volume creating said pressure, and the fluence φsatisfies equation: where: P=pressure to eject the target tissue t Γ=dimensionless strength parameter of the target tissue.