Method for transurethral delivery of thermal therapy to tissue

Abstract

An apparatus for applying thermal energy to a prostate gland, comprising a support tube having a longitudinal passageway, a power lead channeled through the longitudinal central passageway and an ultrasound crystal disposed around at least part of the support tube. The ultrasound crystal is coupled to the power lead which provides the power to energize the ultrasound crystal and generate ultrasound energy providing thermal therapy to the prostate gland. The ultrasound crystal further includes inactivated portions for reducing ultrasound energy directed to the rectal wall of the patient. A sealant is disposed in contact with the ultrasound crystal allowing vibration necessary for efficient ultrasound energy radiation for the thermal therapy of the prostate gland.

1 . A method for applying thermal therapy to a prostate gland of a patient, the method comprising:
 inserting an ultrasound applicator within the urethra adjacent to a tissue target region in the patient;   delivering power to the ultrasound applicator to generate ultrasound energy; and   directing the ultrasound energy to selectively treat a region of the prostate gland.   
     
     
         2 . A method as recited in  claim 1 , wherein directing the ultrasound energy comprises shaping a distribution pattern of the ultrasound energy to produce an angular treatment pattern. 
     
     
         3 . A method as recited in  claim 2 , wherein the pattern is shaped to localize the ultrasound energy to an anterior and lateral region in the patient's tissue. 
     
     
         4 . A method as recited in  claim 2 , wherein the pattern is shaped to protect a region of rectal mucosa. 
     
     
         5 . A method as recited in  claim 4 , wherein selectively treating a region of the prostate gland comprises heating sub-mucosal layers of urethral tissue while avoiding damage to the mucosal layer. 
     
     
         6 . A method as recited in  claim 5 , wherein the pattern is shaped to avoid heating a region of rectal mucosa. 
     
     
         7 . A method as in recited  claim 1 , further comprising controlling the ultrasound energy pattern to control the extent of a longitudinal energy distribution. 
     
     
         8 . A method as in recited  claim 7 , further comprising dynamically altering the longitudinal energy distribution. 
     
     
         9 . A method as recited in  claim 8 , wherein the energy pattern is dynamically altered in response to one or more of the following: tissue heterogeneities; thermally induced changes in blood perfusion; or to tailor the size of the treatment region. 
     
     
         10 . A method as recited in  claim 1 , wherein inserting an ultrasound catheter comprises transurethral delivery of the ultrasound applicator. 
     
     
         11 . A method as recited in  claim 1 , further comprising delivering a cooling fluid to the ultrasound applicator to selectively cool a non-target region of the patient. 
     
     
         12 . A method as recited in  claim 1 , further comprising:
 measuring the tissue temperature during treatment; and   adjusting the delivery of ultrasound energy in response to the tissue temperature measurement.   
     
     
         13 . A method for transurethral delivery of thermal therapy to a prostate gland of a patient, the method comprising:
 inserting an ultrasound applicator within the urethra adjacent to a tissue target region in the patient;   delivering power to the ultrasound transducer to generate ultrasound energy; and   directing the ultrasound energy to selectively treat a region of the prostate gland.   
     
     
         14 . A method as recited in  claim 13 , wherein directing the ultrasound energy comprises shaping an ultrasound energy distribution pattern generated by the ultrasound transducer to produce an angular treatment pattern. 
     
     
         15 . A method as recited in  claim 13 , wherein the ultrasound applicator further comprises an outer cover surrounding the ultrasound transducer, the method further comprising delivering a cooling fluid to the ultrasound applicator, the fluid disposed between the ultrasound transducer and the outer cover, wherein the fluid selectively cools a non-target region of the patient. 
     
     
         16 . A method as recited in  claim 13 , wherein directing the ultrasound energy comprises translating the ultrasound applicator within the tissue target region of the patient to selectively treat a region of the prostate gland. 
     
     
         17 . A method as recited in  claim 13 , wherein directing the ultrasound energy comprises rotating the ultrasound applicator within the tissue target region of the patient to selectively treat a region of the prostate gland. 
     
     
         18 . A method for transurethral delivery of thermal therapy to a prostate gland of a patient, the method comprising:
 inserting an ultrasound applicator within the urethra adjacent to a tissue target region in the patient, the ultrasound applicator comprising a support member and a plurality of spaced-apart ultrasound transducers coupled thereof;   delivering power to the ultrasound transducers to generate ultrasound energy; and   directing the ultrasound energy to selectively treat a region of the prostate gland.   
     
     
         19 . A method as recited in  claim 18 , wherein delivering power to the ultrasound transducers comprises delivering power to individual transducers, and wherein directing the ultrasound energy comprises controlling an ultrasound energy distribution pattern to control the extent of longitudinal energy distribution. 
     
     
         20 . A method as recited in clam 19, wherein the extent of longitudinal energy distribution is dynamically altered in response to one or more of the following: tissue heterogeneities; thermally induced changes in blood perfusion; or to tailor the size of the treatment region. 
     
     
         21 . A method as recited in  claim 18 , wherein the ultrasound applicator further comprises an outer cover surrounding the ultrasound transducers, the method further comprising delivering a cooling fluid to the ultrasound applicator, the fluid disposed between the ultrasound transducers and the outer cover, wherein the fluid selectively cools a non-target region of the patient.