Laser modulation for coagulation

Patent metadata

Field	Value
Publication number	US-2016354147-A1
Application number	US-201615240881-A
Country	US
Kind code	A1
Filing date	Aug 18, 2016
Priority date	Mar 27, 2009
Publication date	Dec 8, 2016
Grant date	—

Abstract

An apparatus ( 100 ) has a pump module ( 104 ) providing pump energy, a resonator ( 106 ) and a controller ( 187 ). The resonator ( 106 ) includes a gain medium ( 102 ) receiving the pump energy from the pump module and producing light; reflective surfaces ( 110, 156, 158, 160, 162 ) reflecting light produced by the gain medium back toward the gain medium; and a variable light attenuator ( 152 ) receiving light produced by the gain medium. The controller ( 187 ) controls the amount of light attenuated by the variable light attenuator such that the apparatus emits windows ( 306, 308, 310 ) of pulses of laser light at spaced time intervals, each window containing a plurality of pulses of laser light and each interval ( 326, 327 ) between windows being larger than an interval ( 318 ) between pulses within a window. The emitted windows of pulses ( 320, 322 ) of laser light heat tissue to a temperature that causes coagulation without vaporization.

First claim

What is claimed is:

1 . An apparatus ( 100 ) comprising:
a pump module ( 104 ) providing pump energy; a resonator ( 106 ) comprising:
a gain medium ( 102 )receiving the pump energy from the pump module and producing light;
at least two at least partially reflective surfaces ( 110 , 156 , 158 , 160 , 162 ) reflecting light produced by the gain medium back toward the gain medium;
a variable light attenuator ( 152 ) receiving light produced by the gain medium;
a controller ( 187 ) that controls the amount of light attenuated by the variable light attenuator such that the apparatus emits windows ( 306 , 308 , 310 ) of pulses of laser light at spaced time intervals, each window containing a plurality of pulses of laser light and each interval ( 326 , 327 ) between windows being larger than an interval ( 318 ) between pulses within a window, the duration ( 324 ) of the windows and the duration ( 328 ) of the intervals between windows being such that the emitted windows of pulses ( 320 , 322 ) of laser light heat tissue to a temperature that causes coagulation.

2 . The apparatus of claim 1 wherein the duration ( 324 ) of the windows and the duration ( 328 ) of the intervals between windows are such that the emitted windows of pulses ( 320 , 322 ) of laser light do not cause vaporization of tissue.

3 . The apparatus of claim 2 further comprising a user input device ( 198 ) that allows the user to select between a vaporization mode and a coagulation mode, wherein when the user selects the vaporization mode the laser production system produces a continuous train ( 404 ) of pulses of laser light that vaporizes tissue and when the user selects the coagulation mode, the laser production system produces the windows ( 306 , 308 , 310 ) of pulses of laser light.

4 . The apparatus of claim 1 wherein when the variable light attenuator ( 152 ) attenuates more light, the apparatus produces less laser light.

5 . The apparatus of claim 4 wherein the controller ( 187 ) comprises;
a driver ( 180 ) producing a driver signal ( 178 ), the driver having an input ( 184 ) for turning the driver signal on and off, the driver signal such that when the driver signal is on the light attenuator ( 152 ) attenuates more light than when the driver signal is off;
a timer ( 194 ), coupled to the input ( 184 ) of the driver for turning the driver signal ( 178 ) on and off and applying a timer signal on the input ( 184 ) of the driver for turning the driver signal on and off, the timer providing a cyclical timer signal in a first mode of operation and a static timer signal in a second mode of operation, the timer having a frequency input ( 189 ) that defines the frequency of the cyclical timer signal and a duration input ( 191 ) that defines a length of time that the timer signal turns the driver signal off during the cyclical timer signal.

6 . The apparatus of claim 5 wherein the static timer signal turns the driver signal ( 178 ) on.

7 . The apparatus of claim 6 wherein the driver further comprises a magnitude input ( 182 ) that receives a magnitude value ( 188 ) used to set the magnitude ( 702 ) of the driver signal, wherein a larger magnitude driver signal causes the light attenuator ( 152 ) to attenuate more light than a smaller magnitude driver signal and wherein the apparatus further comprises a processor executing computer-executable instructions that cause the processor to decrease the magnitude value ( 188 ) at the end of an interval between windows.

8 . A method comprising:
receiving ( 904 ) an input indicating that a medical laser system ( 100 ) is to be placed in a vaporization mode; based on the input indicating that the medical laser system is to be placed in the vaporization mode, controlling ( 908 ) the medical laser system so that the medical laser system emits a continuous series of micropulses ( 404 ) of laser light; receiving ( 912 ) an input indicating that the medical laser system is to be placed in a coagulation mode; and based on the input indicating that the medical laser system is to be placed in a coagulation mode, controlling ( 914 ) the medical laser system so that the medical laser system emits a series of macropulses ( 306 , 308 , 310 ) of laser light, each macropulse comprising a series of micropulses ( 320 , 322 ) of laser light and the macropulses in the series separated by a time interval ( 328 ) that is longer than a time interval ( 318 ) between micropulses within a macropulse.

9 . The method of claim 8 wherein controlling the medical laser system so that the medical laser system emits a series of macropulses of laser light comprises controlling a q-switch ( 152 ) in the medical laser system.

10 . The method of claim 8 wherein each macropulse has a duration ( 324 ) and wherein the duration ( 324 ) of the macropulses and the time interval ( 328 ) between macropulses are such that the laser light emitted by the medical laser system is insufficient for performing tissue vaporization.

11 . The method of claim 10 wherein the duration of each macropulse is between 5 and 30 milliseconds.

12 . The method of claim 11 wherein the time interval between macropulses is 60 milliseconds.

13 . The method of claim 8 wherein the series of micropulses within a macropulse is at the same frequency as the continuous series of micropulses.

14 . A method comprising:
placing ( 910 , 914 ) a laser system ( 100 ) in a coagulation mode such that the laser system produces sets ( 306 , 308 , 310 ) of pulses of laser light, wherein pulses within a set are separated by a first time interval ( 318 ) and the sets of pulses are separated from each other by a second time interval ( 328 ), wherein the second time interval is larger than the first time interval; and aiming ( 900 ) the laser light at tissue to cause coagulation without causing vaporization of tissue.

15 . The method of claim 14 further comprising before placing the laser system in the coagulation mode:
placing ( 900 , 904 ) the laser system in a vaporization mode such that the laser system produces a continuous ( 404 ) series of pulses of laser light; and
aiming the laser light at tissue to cause ( 908 ) vaporization of tissue.

16 . The method of claim 15 wherein the pulses in the continuous series of pulses of the vaporization mode occur at the same frequency as the pulses in the sets of pulses of the coagulation mode.

17 . The method of claim 16 wherein the pulses in the continuous series of pulses of the vaporization mode occur with the same peak intensity ( 350 , 450 ) as the pulses in the sets of pulses of the coagulation mode.

18 . The method of claim 14 further comprising using an interface ( 200 ) to set a first power level ( 202 ) for the laser light emitted in the vaporization mode and a second power level ( 204 ) for the laser light emitted in the coagulation mode.

19 . The method of claim 14 wherein the sets of pulses have a duration of between 5 and 30 milliseconds and the second time interval is between 60 and 100 milliseconds.

20 . The method of claim 19 wherein the pulses within a set of pulses occur with a frequency of 15 kHz.

Assignees

• Boston Scient Scimed Inc

Inventors

• Kang Hyun Wook
• Nemeyer Raymond Adam
• Hodel Michael Ray

Classifications

• H01S3/109

  Frequency multiplication, e.g. harmonic generation · CPC title

• H01S3/10046

  Pulse repetition rate control (H01S3/11 takes precedence) · CPC title

• H01S3/1643

  YAG · CPC title

• A61B18/20 Primary

  using laser · CPC title

• A61B2017/00172

  Pulse trains, bursts, intermittent continuous operation · CPC title