Systems and methods for therapeutic agent delivery

A method of monitoring a level of dispersal of a therapeutic agent into a target tissue, the method comprising:

• energizing an ultrasound transducer to deliver ultrasound energy toward a bolus of injected solution including the therapeutic agent dissolved therein to disperse the bolus of injected solution with the therapeutic agent into interstitial space of the target tissue;
• monitoring the level of dispersal of the bolus of injected solution with the therapeutic agent into the interstitial space of the target tissue, with an acoustic sensor in response to the ultrasound delivered by the ultrasound transducer, by monitoring an acoustic response of the target tissue or the injected solution to the applied ultrasound during an ultrasound application;
• adjusting the ultrasound delivery, with a controller coupled to the ultrasound transducer and the acoustic sensor, wherein adjusting is based on the monitored acoustic response of the target tissue or the injected solution to the applied ultrasound;
• measuring a baseline acoustic response from the target tissue, with the acoustic sensor, wherein the baseline acoustic response of the target tissue is associated with the acoustic response of the target tissue prior to injection of the solution;
• and
• identifying an end point for the ultrasound delivery, with the controller, by comparing the monitored acoustic response of the target tissue to the measured baseline acoustic response of the target tissue and ceasing the ultrasound delivery upon reaching the end point so as to facilitate delivery of ultrasound energy for a duration to disperse the injected solution within the target tissue while inhibiting tissue damage associated with prolonged ultrasound output, wherein comparing the monitored acoustic response of the target tissue to the measured baseline acoustic response of the target tissue comprises determining when the monitored acoustic response of the target tissue returns to within a predetermined threshold of the measured baseline acoustic response of the target tissue.