Method and device for non-invasive regulation of temperature with radiation, especially laser radiation of biological tissue

• US 6,830,567 B2
• Filed: 07/24/2002
• Issued: 12/14/2004
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Medizinisches Laserzentraum Luebeck
• Original Assignee: Medizinisches Laserzentrum Luebech GmbH
• Inventors: Schuele, Georg, Brinkmann, Ralf
• Primary Examiner(s): Gibson, Roy D.
• Assistant Examiner(s): Johnson, III, Henry M
• Application Number:
  US10/201,250
• Publication Number:
  US 20030032949A1
• Time in Patent Office: 874 Days
• Field of Search: 606/4, 606/27, 606/28, 606/5, 374/17, 600/402-405, 128/898
• US Class Current: 606/4
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00128 related to intensity or progress of surgical action
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61F 2009/00844 Feedback systems
• CPC Class Codes: A61F 2009/00863 Retina
• CPC Class Codes: A61F 9/00727 Apparatus for retinal reattachment
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00814 Laser features or special beam parameters therefor
• CPC Class Codes: A61F 9/00821 for coagulation
• CPC Class Codes: A61F 9/009 Auxiliary devices making contact with the eyeball and coupling in laser light, e.g. goniolenses apparatus for eye examination A61B3/0008

Abstract

A method and a system for the non-invasive temperature determination on biological tissue, particularly at the fundus of the eye, treated by a treatment radiation, particularly laser radiation, wherein, during the respective irradiation time, at essentially identical time intervals, additional radiation pulses of a shorter pulse duration and a lower energy are aimed at the treated biological tissue, the resulting tissue expansions and/or contractions being detected by a pressure measurement or optical measurement and, from the measuring signals, the absolute temperature values are determined and optionally the treatment radiation is controlled as a function thereof.

Claims

1. Method for non-invasive determination of temperature on biological tissue, including the fundus of an eye, treated by radiation, comprising

during a respective irradiation period by the treatment radiation, aiming additional radiation, which have pulses of a shorter pulse duration and a lower energy than those pulses generated during the treatment radiation at the biological tissue, or switching off the treatment radiation for a short time and switching the treatment radiation back on,

detecting resulting at least one of tissue expansions and contractions by one of a pressure or an optical measurement, and

from a signal from the measurement, determining at least one of temperature and the temperature rise.

2. Method according to claim 1, wherein, during the optical measurement, the at least one of tissue expansions and contraction is detected by interference measurement.

3. Method according to claim 1, wherein, during the pressure measurement, an electric pressure transient is formed for analysis during the temperature determination.

4. Method according to claim 1, wherein the additional radiation pulses or the short-duration switch-off of the treatment radiation occur at substantially the same time intervals.

5. Method according to claim 1, wherein the treatment radiation is controlled as a function of the determined temperature.

6. Method according to claim 1, further comprising determining a temperature at the fundus of an eye which is treated by radiation.

7. Method according to claim 1, wherein during or immediately after switch-on of the treatment radiation, a measuring signal standardized to normal body temperature is obtained from the resulting tissue expansion or contraction.

8. Method according to claim 1, wherein, based on continuous monitoring of temperature during the respective irradiation period of the treatment radiation, control of the treatment radiation is carried out as a function of the respective determined temperature at an irradiation site.

9. System for non-invasive determination of temperature of biological tissue which is treated by radiation, including laser radiation, with a defined treatment time, comprising

a treatment radiation source for generating the treatment radiation,

a control device configured to control the treatment radiation source during the defined treatment time,

an irradiation lens system for aiming the treatment radiation at the biological tissue,

an additional radiation source which, during the treatment time, is coupleable into the irradiation lens system for supplying additional radiation pulses,

a detector for measuring by at least one of acoustically and optically at least one of expansions and contractions caused by the radiation, and

an analyzing device which has a calibration curve indicating proportionality of the at least one of acoustically and optically detected measuring signals to the temperature and so as to convert the detected measurement into a temperature value.

10. System according to claim 9, wherein the radiation pulses of the additional beam source have a lower energy than the treatment radiation, and pulse duration is less than the respectively defined irradiation time.

11. System according to claim 10, wherein the pulse duration of the additional radiation pulses or a switch-off time of the treatment radiation is smaller by at least a factor of 10² than the respective irradiation time of the treatment radiation.

12. System according to claim 10, wherein the pulse duration of the additional radiation pulses or the switch-off time of the treatment radiation is in the ns range.

13. System according to claim 9, wherein the analyzing device is operatively connected to the control device.

14. System according to claim 9, wherein the analyzing device is operatively connected to a temperature indicating device which indicates absolute temperature values.

15. System according to claim 9, wherein the detector is a measuring converter coupleable acoustically or optically to the human eye.

16. System according to claim 15, wherein the detector is coupleable to the treated eye by a contact lens placeable on the eye.

17. System for non-invasive temperature determination of biological tissue which is treated by radiation, including laser radiation with a defined treatment time, comprising

a treatment radiation source for generating the treatment radiation,

a control device configured to control the treatment radiation source during the defined treatment time,

an irradiation lens system for aiming the treatment radiation at the biological tissue,

a switching device operatively controlled by the control device during the respectively defined irradiation time, to switch the treatment radiation source off for a short duration and then back on,

a detector for measuring at least one of acoustically and optically at least one of expansions and contractions caused by the radiation, and

an analyzing device which has a calibration curve indicating proportionality of the at least one of the acoustically and optically detected measurements to temperature so as to convert the measurement signal into a temperature value.