Adaptive control of optical pulses for laser medicine
View Patent ↗Tissue is treated by irradiating it with a sequence of optical pulses that are directed in sequence to various sites on the tissue. During the irradiation sequence, one or more tissue properties are measured at a site(s) that has already been irradiated. These measurements are used to adjust the parameters of subsequent optical pulses in the sequence.
1. A method for automatically controlling treatment of tissue with optical pulses, comprising:
irradiating a first site in a portion of tissue with a first optical pulse;
following the irradiation, automatically making a measurement of a tissue property at the first site;
based on the measurement, automatically adjusting a parameter of a second optical pulse according to an algorithm selected from the group consisting of a moving simplex algorithm, a neural net algorithm, and a fuzzy logic algorithm;
irradiating a second site in the portion of tissue with the second optical pulse in order to provide treatment of the tissue at a pre-determined treatment level;
irradiating other sites in the portion of tissue with other optical pulses;
following the irradiation, automatically making measurements of the tissue property at the other sites; and
taking a weighted average of the measurements,
wherein the step of automatically adjusting the parameter of the second optical pulse is based on the weighted average of the measurements.
2. The method of claim 1 , wherein irradiating the first site with the first optical pulse and irradiating the second site with the second optical pulse both occur by laser scanning.
3. The method of claim 1 , further comprising:
irradiating the first site with a first sequence of multiple optical pulses that includes the first optical pulse.
4. The method of claim 1 , further comprising:
irradiating multiple sites with a first sequence of optical pulses, said irradiation including irradiating the first site with the first optical pulse.
5. The method of claim 1 , wherein the parameter of the second optical pulse includes a parameter selected from the group consisting of an energy of the optical pulse, a duration of the optical pulse, a temporal shape of the optical pulse, a spatial shape of the optical pulse, a propagation direction of the optical pulse relative to the tissue surface, a focusing characteristic of the optical pulse, a polarization of the optical pulse, and a wavelength spectrum of the optical pulse.
6. The method of claim 1 , wherein the tissue property includes a property selected from the group consisting of mechanical density, electrical capacitance, dielectric constant, birefringence, opacity, optical reflectivity, absorption, extinction, elasticity, water fraction, melanin fraction, hemoglobin fraction, oxyhemoglobin fraction, and fraction of foreign matter.
7. The method of claim 1 , wherein the tissue property includes a temperature of the tissue.
8. The method of claim 1 , wherein automatically making the measurement of the tissue property at the first site comprises:
making a measurement of a change in the tissue property at the first site.
9. The method of claim 8 , wherein automatically making the measurement of the change in the tissue property at the first site comprises:
making a measurement of a change in the tissue property before irradiation of the site by the first optical pulse and after irradiation of the site by the first optical pulse.
10. The method of claim 1 , wherein making the measurement of the tissue property comprises:
measuring two or more tissue properties.
11. The method of claim 10 , wherein automatically adjusting the parameter of the second optical pulse comprises:
automatically adjusting two or more parameters of the second optical pulse based on the measurements.
12. The method of claim 1 , further comprising:
determining a characteristic of the tissue based on the measurement.
13. The method of claim 12 , wherein automatically adjusting the parameter of the second optical pulse comprises:
automatically adjusting a parameter of the second optical pulse in response to the determined characteristic.
14. The method of claim 1 , wherein the measurement and the irradiation by the second optical pulse are separated by less than 1 second.
15. The method of claim 1 , wherein the weighted average is an exponential weighted average.
16. The method of claim 1 , wherein the weighted average is weighted according to time.
17. The method of claim 1 , wherein the weighted average is weighted according to distance from the second site.
18. A method for automatically controlling treatment of tissue with optical pulses, comprising:
irradiating a first site in a portion of tissue with a first optical pulse;
following the irradiation, automatically making a measurement of a tissue property at the first site;
based on the measurement, automatically adjusting a parameter of a second optical pulse;
irradiating a second site in the portion of tissue with the second optical pulse in order to provide treatment of the tissue at a pre-determined treatment level;
irradiating other sites in the portion of tissue with other optical pulses;
following the irradiation, automatically making measurements of the tissue property at the other sites; and
taking a weighted average of the measurements,
wherein the step of automatically adjusting a parameter of the second optical pulse is based on the weighted average of the measurements.
19. The method of claim 18 , wherein the weighted average is an exponential weighted average.
20. The method of claim 18 , wherein the weighted average is weighted according to time.
21. The method of claim 18 , wherein the weighted average is weighted according to distance from the second site.
22. The method of claim 18 , wherein irradiating the first site with the first optical pulse and irradiating the second site with the second optical pulse both occur by laser scanning.
23. The method of claim 18 , further comprising:
irradiating the first site with a first sequence of multiple optical pulses that includes the first optical pulse.
24. The method of claim 18 , further comprising:
irradiating multiple sites with a first sequence of optical pulses, said irradiation including irradiating the first site with the first optical pulse.
25. The method of claim 18 , wherein the parameter of the second optical pulse includes a parameter selected from the group consisting of an energy of the optical pulse, a duration of the optical pulse, a temporal shape of the optical pulse, a spatial shape of the optical pulse, a propagation direction of the optical pulse relative to the tissue surface, a focusing characteristic of the optical pulse, a polarization of the optical pulse, and a wavelength spectrum of the optical pulse.
26. The method of claim 18 , wherein the tissue property includes a property selected from the group consisting of mechanical density, electrical capacitance, dielectric constant, birefringence, opacity, optical reflectivity, absorption, extinction, elasticity, water fraction, melanin fraction, hemoglobin fraction, oxyhemoglobin fraction, and fraction of foreign matter.
27. The method of claim 18 , wherein the tissue property includes a temperature of the tissue.
28. The method of claim 18 , wherein automatically making the measurement of the tissue property at the first site comprises:
making a measurement of a change in the tissue property at the first site.
29. The method of claim 28 , wherein automatically making the measurement of the change in the tissue property at the first site comprises:
making a measurement of a change in the tissue property before irradiation of the site by the first optical pulse and after irradiation of the site by the first optical pulse.
30. The method of claim 18 , wherein making the measurement of the tissue property comprises:
measuring two or more tissue properties.
31. The method of claim 30 , wherein automatically adjusting the parameter of the second optical pulse comprises:
automatically adjusting two or more parameters of the second optical pulse based on the measurements.
32. The method of claim 18 , further comprising:
determining a characteristic of the tissue based on the measurement.
33. The method of claim 32 , wherein automatically adjusting the parameter of the second optical pulse comprises:
automatically adjusting a parameter of the second optical pulse in response to the determined characteristic.
34. The method of claim 18 , wherein the measurement and the irradiation by the second optical pulse are separated by less than 1 second.