Method and apparatus for obtaining quantitative temperature measurements in prostate and other tissue undergoing thermal therapy treatment

• US 20070239062A1
• Filed: 03/27/2007
• Published: 10/11/2007
• Est. Priority Date: 03/09/2005
• Status: Active Grant

• Current Assignee: Sunnybrook Health Sciences Centre
• Original Assignee: Sunnybrook Health Sciences Centre
• Inventors: Chopra, Rajiv, Bronskill, Michael, Tang, Kee
• Granted Patent: US 8,801,701 B2
• Time in Patent Office: Days
• US Class Current: 600/549
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2090/374 NMR or MRI
• 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: A61B 5/4381 Prostate evaluation or disorder diagnosis
• CPC Class Codes: A61N 7/022 intracavitary
• CPC Class Codes: G01R 33/4804 Spatially selective measurement of temperature or pH

Abstract

The invention provides a method and apparatus for monitoring a thermal effect of a conformal thermal treatment to diseased tissue in a target volume. The method includes acquiring a reference image of the volume containing the diseased tissue at a first position of the device, determining a baseline temperature distribution of the reference image, acquiring an image of the volume containing the diseased tissue while delivering a treatment to the volume, performing a phase subtraction between the image and the reference image to determine a change in phase between the image and the reference image and determining a current spatial temperature distribution in the volume containing the diseased tissue.

Claims

1. A method for quantitative monitoring of an effect of a thermal treatment of tissue in a target volume to be treated, comprising:

acquiring at least one reference image of the target volume for at least one respective position of a thermal treatment device at least partially inserted into a patient'"'"'s body such that the thermal treatment device is substantially within or proximal to the target volume being treated;

determining a first temperature distribution corresponding to the at least one reference image;

acquiring at least one additional image of the target volume, corresponding to the at least one respective reference image, with the treatment device substantially at the respective at least one position, while substantially simultaneously delivering a thermal treatment from the thermal treatment device to the target volume;

performing a phase subtraction between the at least one additional image and the respective at least one reference image to determine a change in phase between the at least one additional image and the at least one reference image; and

determining a second spatial temperature distribution in the target volume as a result of said delivery of said thermal treatment.

2. The method of claim 1 wherein determining the second spatial temperature distribution in the target volume comprises calculating a temperature change between the at least one additional image and the at least one reference image;

and

adding said temperature change to the first temperature distribution.

3. The method of claim 2, wherein the temperature change is calculated using a proton resonant frequency shift relationship.

4. The method of claim 1, further comprising determining a phase change in a untreated tissue that is proximal to the treated target volume.

5. The method of claim 1, further comprising compensating for a drift in a phase of the at least one reference image.

6. The method of claim 1, further comprising defining a boundary surrounding said target volume.

7. The method of claim 6, wherein monitoring a thermal effect comprises quantitative monitoring of a thermal effect along the boundary surrounding said target volume.

8. The method of claim 1, wherein the thermal effect is a temperature rise.

9. The method of claim 1, wherein the thermal effect is a thermal dose.

10. The method of claim 1, wherein the thermal effect is a maximal temperature.

11. The method of claim 1, wherein acquiring a reference image comprises acquiring a magnetic resonance image (MRI) of the target volume.

12. The method of claim 1, wherein delivering a treatment comprises heating the tissue within the target volume using an ultrasonic applicator to a predetermined temperature level.

13. The method of claim 1, wherein delivering a treatment comprises delivering a predetermined thermal dose to the tissue within the target volume.

14. The method of claim 1, wherein the at least one reference image is acquired following an initial preparation of the tissue within the target volume.

15. The method of claim 14, wherein said initial preparation includes a step of application of a pharmaceutical agent to reduce tissue movement within the target volume.

16. The method of claim 14, wherein said initial preparation includes a step of mechanical restraint of the tissue within the target volume to reduce tissue movement within the target volume.

17. The method of claim 1, wherein the at least one reference image and the at least one additional image correspond to certain respective positions of the treatment device within the patient'"'"'s body.

18. The method of claim 1, wherein the phase subtraction is performed for respective reference and additional images that are acquired while the treatment device is positioned at substantially the same position.

19. The method of claim 1, wherein the step of acquiring the one or more reference images is followed by a step of stabilizing a temperature of a region of tissue in physical proximity to the treatment device by application of a cooling fluid to cool said region of tissue in conjunction with the thermal treatment.

20. A system for monitoring a thermal effect of a conformal thermal treatment to diseased tissue in a target volume, comprising:

a thermal treatment device adapted for at least partial insertion into a patient'"'"'s body and being at least partially disposed within or proximal to the target volume and configured to deliver a thermal treatment to tissue within the target volume;

the thermal treatment device also being adapted for coupling with an imaging apparatus configured to acquire at least one reference image of the target volume for a given position of the thermal treatment device, said imaging apparatus further being configured to acquire at least one additional image of the treatment volume at substantially the same given position of the thermal applicator, substantially simultaneously with delivery of the thermal treatment to the tissue within the target volume; and

a thermometry module configured to determine a respective first temperature distribution for the at least one reference image and further configured to perform a phase subtraction between the respective at least one additional image and the at least one reference image to determine a respective change in phase between the respective at least one additional image and the at least one reference image;

wherein the system is adapted to determine a second spatial temperature distribution over the target volume as a result of said delivery of said thermal treatment.

21. The system of claim 20, wherein the imaging apparatus comprises a magnetic resonance imaging (MRI) device.

22. The system of claim 20, wherein the thermometry module includes a temperature sensor positioned proximal to the treatment volume.

23. The system of claim 20, wherein the thermometry module is further configured to:

calculate a temperature change between an additional image acquired substantially during application of thermal therapy and a reference image acquired before thermal therapy; and

add the temperature change between the additional image and the reference image, to a baseline temperature distribution.

24. The system of claim 20, further comprising a temperature-stabilizing element to stabilize a temperature of tissue physically proximal to the treatment device.

25. The system of claim 20, further comprising a fluid cooling apparatus coupled to the thermal treatment device to controllably cool tissue in physical proximity to the thermal treatment device.