TEMPERATURE PROFILE MAPPING AND GUIDED THERMOTHERAPY

• US 20110066035A1
• Filed: 03/02/2009
• Published: 03/17/2011
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Tomophase Corporation
• Original Assignee: Tomophase Corporation
• Inventors: Vertikov, Andrey, Li, Xiao-Li, Norris, Peter E.
• Granted Patent: US 8,452,383 B2
• Time in Patent Office: Days
• US Class Current: 600/478
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2017/320069 for ablating tissue
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/6852 Catheters

Abstract

Techniques, apparatus and systems that use an optical probe head to deliver light to a target and to collect light from the target for imaging and monitoring a target while a separate radiation is applied to treat the target.

Claims

1. An endoscope device, comprising:

an optical catheter comprising an optical fiber to guide an optical imaging beam and an optical probe head, located at a distal end of the fiber to direct the optical imaging beam from the fiber to a target and to receive light returned from the target under illumination of the optical imaging beam;

a detection module to process the light returned from the target under illumination of the optical imaging beam to measure a temperature at a location illuminated by the optical imaging beam;

an energy source that produces energy that is applied to the target to raise a temperature at a location of the target where the energy is applied; and

a control mechanism that controls the energy source to set a power level of the energy produced by the energy source based on the measured temperature from the detection module.

2. The device of claim 1, wherein:

the energy source is an RF source, and

the device comprises an RF applicator engaged to the sheath to receive RF energy from the RF source and to apply the received RF energy to the target.

3. The device of claim 2, wherein:

the RF applicator includes a hollow tube that both conducts the RF energy for application of the RF energy to the target and carries a coolant inside the hollow tube to cool a surface of the target to allow a temperature at a location underneath the surface to be higher than a temperature of the surface under application of the RF energy.

4. The device of claim 2, wherein:

the RF applicator surrounds the optical catheter and allows the optical catheter to rotate within the sheath.

5. The device of claim 4, comprising:

a housing comprising a hollow working channel, in which the optical catheter is placed to rotate within the hollow working channel, and

an RF transmission path connecting the RF applicator and the RF source RF applicator and located inside the hollow working channel.

6. The device of claim 5, wherein:

the RF applicator comprises an expandable basket that can carry RF energy, the expandable basket structured to expand when the expandable basket is located outside a distal opening of the hollow working channel and to collapse when the expandable basket is pulled into the distal opening of the hollow working channel.

7. The device of claim 1, wherein:

the optical probe head of the optical catheter comprises a prism that reflects the optical imaging beam from the fiber to a location of the target and collects the light returned from the target into the fiber.

8. The device of claim 1, wherein:

the optical probe head of the optical catheter splits the optical imaging beam from the fiber into a first portion that is directed to the target and a second portion that does not reach the target and is reflected back to the fiber to co-propagate with the light returned from the target that is collected by the optical probe head along the fiber, and

the detection module receives both the second portion and the light returned from the target via the fiber and processes the received second portion and the light returned from the target to extract the measured temperature.

9. The device as in claim 8, wherein:

the detection module comprises an optical differential delay unit to produce and control a relative phase delay between the second portion and the light returned from the target via the fiber and performs a time-domain Fourier transform of the obtained signals at different relative phase delays.

10. The device as in claim 8, wherein:

the detection module performs a frequency-domain Fourier transform of the spectra of the light from the optical probe head.

11. The device of claim 1, comprising:

a beam scanning mechanism to scan the optical imaging beam on the target to direct the optical imaging beam to different positions on the target, wherein the detection module changes a phase delay between two portions of received light of the second portion and the light returned from the target via the fiber at each location of the optical imaging beam on the target to obtain an image of the each location of the target.

12. The device of claim 1, wherein:

the detection module processes received light of the second portion and the light returned from the target via the fiber to measure a change of a density of the target caused by application of the energy from the energy source.

13. The device of claim 1, comprising:

a mechanism to cool a surface of the target to allow a temperature at a location underneath the surface to be higher than a temperature of the surface under application of the energy from the energy source.

14. The device of claim 13, wherein:

the mechanism comprises a tube that carries a cooling flow to pass a location near the distal end of the optical catheter.

15. The device of claim 1, wherein:

the energy source produces a laser beam, separate from the optical imaging beam, as the energy applied to the target.

16. The device of claim 1, wherein:

the energy source generates a microwave energy signal as the energy applied to the target.

17. The device of claim 1, wherein:

the energy source generates an ultrasound signal as the energy applied to the target.

18. A method for guiding the application of a thermotherapeutic radiation to a target tissue, comprising:

using an optical catheter comprising an optical fiber to guide an optical imaging beam to direct the optical imaging beam from the fiber to a target and to receive light returned from the target under illumination of the optical imaging beam;

processing the light returned from the target tissue under illumination of the optical imaging beam to measure a temperature at a location illuminated by the optical imaging beam;

applying a thermotherapeutic energy to the target tissue to raise a temperature at a location of the target tissue where the energy is applied; and

controlling an amount of the thermotherapeutic energy applied to the target tissue, based on the measured temperature by using the optical imaging beam, to control the temperature at the target tissue between a low limit above which a thermotherapeutic effect is present and a high limit above which a damage to the target tissue occurs.

19. The method as in claim 18, comprising:

using the optical imaging beam to obtain an image of a location of the target tissue illuminated by the optical imaging beam, in addition to obtaining the measured temperature; and

using both the measured temperature and the obtained image from the optical imaging beam to monitor and control application of the thermotherapeutic energy to the target tissue.

20. The method as in claim 18, comprising:

using the optical catheter to split the optical imaging beam from the fiber into a first portion that is directed to the target and a second portion that does not reach the target and is reflected back to the fiber to co-propagate with the light returned from the target tissue.

21. The method as in claim 20, comprising:

producing a relative phase delay between the second portion and the light returned from the target tissue via the fiber to cause an optical interference between the second portion and the light returned from the target tissue;

detecting a change to the optical interference caused by the application of the thermotherapeutic energy to the target tissue to measure a change in density of the target tissue; and

using the measured change in density of the target tissue to obtain the measured temperature.

22. The method as in claim 20, comprising:

performing a frequency-domain Fourier transform of spectra of light in the fiber that combines the light returned from the target tissue and the second portion that does not reach the target to extract a change to the optical interference caused by the application of the thermotherapeutic energy to the target tissue and to measure a change in density of the target tissue; and

using the measured change in density of the target tissue to obtain the measured temperature.

23. The method as in claim 18, comprising:

scanning the optical imaging beam on the target tissue to obtain a two-dimensional map of temperatures at locations of the target tissue; and

using the two-dimensional map of temperatures at locations of the target tissue to control the application of the thermotherapeutic energy to the target tissue.

24. The method as in claim 18, wherein:

the processing of the light returned from the target tissue under illumination of the optical imaging beam comprises;

obtaining image contrasts from the light returned from the target tissue before and after the thermotherapeutic energy;

comparing the obtained image contrasts from the light returned from the target tissue before and after the thermotherapeutic energy to obtain a contrast variation caused by application of the thermotherapeutic energy; and

using the contrast variation to obtained the measured temperature.

25. The method as in claim 18, comprising:

cooling a surface of the target tissue to allow a temperature at a location underneath the surface to be higher than a temperature of the surface under application of the thermotherapeutic energy.

26. The method as in claim 25, wherein:

using a tube that is located near the distal end of the optical catheter to carry a cooling flow to providing the cooling of the surface of the target tissue.

27. An endoscope device for providing guided thermotherapy, comprising:

an endoscope tube comprising a hollow working channel;

an optical catheter comprising an optical fiber located inside the hollow working channel to guide an optical probe beam and, an optical probe head, located at a distal end of the fiber, to reflect a first portion of the optical probe beam back to the fiber and to direct a section portion of the optical probe beam to a target tissue as an optical imaging beam, the optical probe head receiving light returned from the target tissue under illumination of the optical imaging beam to overlap the light returned from the target tissue with the first portion to co-propagate in the fiber away from the optical probe head;

an optical delay device coupled to the fiber to receive the first portion and the light returned from the target tissue to produce a variable relative phase delay between the first portion and the light returned from the target tissue;

an optical detector that detects the light of the first portion and the light returned from the target tissue from the optical delay device;

a processing unit to receive output from the optical detector and to extract a temperature at a location illuminated by the optical imaging beam from information of the target carried by the light returned from the target tissue;

an RF applicator engaged to the endoscope tubing and near the optical probe head to apply RF energy to the target tissue to raise a temperature at a location of the target where the RF energy is applied; and

a control mechanism that controls an amount of the RF energy to be applied by the RF applicator to the target tissue based on the measured temperature.

28. The device as in claim 27, wherein:

the RF applicator includes a hollow tube that both conducts the RF energy for application of the RF energy to the target tissue and carries a cooling liquid or gas inside the hollow tube to cool a surface of the target to allow a temperature at a location underneath the surface to be higher than a temperature of the surface under application of the RF energy.

29. The device as in claim 27, wherein:

the optical probe head includes a partial reflector that reflects the first portion of the optical probe beam back to the fiber and transmits the second portion of the optical probe beam as the optical imaging beam to the target tissue.

30. The device as in claim 27, wherein:

the optical delay device includes a beam splitter to separate the light from the fiber into a first light beam along a first optical path and a second light beam along a second optical path;

a variable optical delay element in one of the first and the second optical paths to cause the relative phase delay between the first light beam and the second light beam; and

a beam combiner to combine the first light beam and the second light beam to produce combined light.