A method of delivering therapy to a target site. The method includes (a) obtaining a base image of the target site, (b) injecting a dose of a mix of a therapeutic agent and a contrast agent into a first injection location at the target site via a needle passing through a catheter, (c) collecting sequential fluoroscopic images of a contrast agent dispersion cloud at the first injection location, (d) determining a contrast agent dispersion area from the sequential fluoroscopic images, (e) determining a therapeutic agent dispersion area from the contrast agent dispersion area, (f) marking the therapeutic agent dispersion area on the base image of the target site, and (g) repeating (b) through (f) until the target site is substantially covered with overlapping therapeutic agent dispersion areas corresponding to a plurality of injections at a plurality of injection locations at the target site.