Abstract: Methods and systems of treating at least one blood vessel involves the application of therapy ultrasound to the blood vessel(s) using one or more dosing conditions. An image of the region of interest is acquired responsive to the applied therapy ultrasound. A change in vascularity of the blood vessel(s) is estimated, responsive to the applied therapy ultrasound, using the acquired image to determine whether to adjust at least one of the dosing conditions. The therapy ultrasound is applied with an intensity to modify the blood vessel(s) without damaging a surrounding tissue. A method of treating a tumor comprises introducing a therapeutic agent into a bloodstream and applying therapy ultrasound to blood vessel(s). The therapy ultrasound, along with an agent, disrupts the blood vessel(s) to limit flow to and from the tumor, thereby retaining the therapeutic agent within the tumor.