Laser system and method for treatment of biologic targets

• US 7,118,562 B2
• Filed: 07/31/2003
• Issued: 10/10/2006
• Est. Priority Date: 04/09/1996
• Status: Expired due to Fees

• Current Assignee: Cynosure Incorporated
• Original Assignee: Cynosure Incorporated
• Inventors: Furumoto, Horace W.
• Primary Examiner(s): FARAH, AHMED M
• Application Number:
  US10/631,213
• Publication Number:
  US 20040024390A1
• Time in Patent Office: 1,167 Days
• Field of Search: 606/3, 606 7- 10, 128/898
• US Class Current: 606/9
• CPC Class Codes: A61B 18/203 applying laser energy to the outside of the body
• CPC Class Codes: A61B 2017/00172 Pulse trains, bursts, intermittent continuous operation
• CPC Class Codes: A61B 2017/22085 light-absorbing A61B2017/22087 takes precedence
• CPC Class Codes: A61B 2018/00452 Skin
• CPC Class Codes: A61B 2018/00476 Hair follicles
• CPC Class Codes: H01S 2301/08 Generation of pulses with special temporal shape or frequency spectrum
• CPC Class Codes: H01S 3/08072 Thermal lensing or thermally induced birefringence; Compensation thereof
• CPC Class Codes: H01S 3/092 of flash lamp H01S3/0937 takes precedence ; flash lamps per se H01J61/80; circuit arrangements for operating flash lamps in general H05B41/30
• CPC Class Codes: H01S 3/1633 BeAl2O4, i.e. Chrysoberyl

Abstract

A long pulse alexandrite laser for treating dermatological specimens is disclosed. The use of alexandrite allows operation in the near-infrared, specifically in a 50 nm range surrounding 755. Infrared in this range allows good penetration while still achieving an acceptable ratio of hemoglobin to melanin absorption In addition, a method and related system for treating biologic tissue with pulse light includes generating a long effective output light pulse comprising a series of sub-pulses having a fractional duty cycle over a selected effective pulse duration, a periodicity that is less than the thermal relaxation time of a targeted structure, and an interpulse-delay between successive sub-pulses that is greater than the thermal relaxation time of non-targeted structures within the treatment area; and delivering the output light to the tissue of a patient.

Claims

1. A method for wearing biologic tissue with pulse light, comprising:

generating a long effective output light pulse comprising a series of sub-pulses having a fractional duty cycle over a selected effective pulse duration, a periodicity that is less than the thermal relaxation time of a targeted structure, and an interpulse-delay between successive sub-pulses that is greater than the thermal relaxation time of non-targeted structures within the treatment area, the targeted structures being substantially adjacent to the non-targeted structures within the treatment area; and

delivering the output light to the tissue of a patient.

2. The method as described in claim 1 wherein the output light pulse comprises a laser light pulse.

3. The method as described in claim 1 wherein the effective pulse duration is approximately equal to the thermal relaxation time of the targeted structure.

4. The method as described in claim 1 wherein the targeted structure comprises blood vessels.

5. The method as described in claim 4 wherein the targeted blood vessels are larger than 30 microns in diameter.

6. The method as described in claim 1 wherein the effective pulse duration is larger than 0.1 msec.

7. The method as described in claim 1 wherein the effective pulse duration is larger than 0.5 msec.

8. The method as described in claim 1 wherein the effective pulse duration is larger than 5 msec.

9. The method as described in claim 1 wherein the effective pulse duration is larger than 50 msec.

10. The method as described in claim 1 wherein the non-targeted structures include nonnal-sized blood-vessels.