Systems and Methods for Coupling an Ultrasound Source to Tissue

Abstract

This disclosure provides systems and methods for sensing coupling of an ultrasound source to a target and for providing a constant average output of power from an ultrasound source. The systems and methods can include a frequency sweep function. The systems and methods can also include receiving reflected energy from an acoustic window and determining a feedback using the reflected energy. The systems and methods can also include comparing the feedback with a threshold level and using the comparison to determine if the ultrasound source is coupled with a target.

1 . A method of sensing coupling of a ultrasound source to a target, the method comprising:
 providing an ultrasound sound source comprising a transducer, an acoustically transparent standoff, an acoustic window at a bottom surface of the standoff, and a frequency sweep function coupled to the transducer;   emitting ultrasound energy from the transducer;   receiving reflected energy;   frequency sweeping the transducer;   determining the feedback from the frequency sweep is above a threshold level;   determining of the source is coupled to the target.   
     
     
         2 . The method according to  claim 1 , wherein if the feedback from the frequency is above the threshold level, then the source is not coupled to the target. 
     
     
         3 . The method according to  claim 1 , wherein if the feedback from the frequency is below the threshold level, then the source is coupled to the target. 
     
     
         4 . The method according to  claim 1 , wherein the window is a half wavelength thick. 
     
     
         5 . The method according to  claim 3 , further comprising providing constant average output power from the source. 
     
     
         6 . The method according to  claim 2 , terminating power to the source. 
     
     
         7 . The method according to  claim 1 , wherein the sweep frequency has a period, which is calculated using a path length of the standoff and the speed of sound. 
     
     
         8 . The method according to  claim 3  further comprising providing ultrasound energy to a target. 
     
     
         9 . A system for determining whether an ultrasound source is coupled to a target, the system comprising:
 an ultrasound source comprising a transducer;   an acoustically transparent standoff coupled to the transducer;   an half wavelength acoustic window at a bottom surface of the standoff, and   a frequency sweep function coupled to the transducer.   
     
     
         10 . The system according to  claim 9 , wherein the half wavelength acoustic window is a reflector when the ultrasound source is not coupled to the target. 
     
     
         11 . The system according to  claim 9 , wherein the half wavelength acoustic window is transparent to ultrasound energy when the ultrasound source is coupled to the target. 
     
     
         12 . The system according to  claim 9 , further comprising a power to transducer termination function in communication with the frequency sweep function. 
     
     
         13 . The system according to  claim 9  wherein the frequency sweep function provides a constant average output power from the ultrasound source when the ultrasound source is coupled to the target. 
     
     
         14 . The system according to  claim 9 , further comprising a lens coupled to the ultrasound source. 
     
     
         15 . A system for providing a constant average output of power from an ultrasound source, the system comprising:
 an ultrasound transducer coupled to a power supply;   a controller in communication with the power supply;   a chirp function in communication with and operable to monitor the ultrasound transducer;   a feedback loop from the chirp function to the controller;   wherein the controller is operable to change a parameter on the transducer based on the feedback to provide a constant average output of power from the ultrasound transducer.   
     
     
         16 . The system according to  claim 15  further comprising a coupling device in acoustic communication with the ultrasound transducer. 
     
     
         17 . The system according to  claim 16 , further comprising a half wavelength acoustic window in acoustic communication with the ultrasound transducer. 
     
     
         18 . The system according to  claim 15 , wherein the coupling device contains a medium configured to be transparent to ultrasound energy. 
     
     
         19 . The system according to  claim 15 , further comprising a contact sensor operable to determine if the ultrasound transducer is coupled to a target. 
     
     
         20 . The system according to  claim 15 , wherein the controller operable to control the power supply to change an amount of power provided to the ultrasound transducer.