A treatment system includes a magnetic targeting catheter and a plurality of MNP. The MNP may include one or more magnetic field-responsive agents and one or more therapeutic agents. The catheter may include an inner shaft having at least one lumen and a fluid delivery balloon adapted to administer a fluid from the inner shaft into a space surrounding the catheter. An expandable mesh formed of a magnetizable material may surround the fluid delivery balloon. The catheter may further include one or more occlusion balloons for controlling blood flow through a vessel in which the catheter is placed. A method of treating a medical condition may include advancing a magnetic targeting catheter to a site, deploying an expandable mesh connected to the catheter, applying a magnetic field to the mesh and depositing a plurality of MNP or cells loaded with MNP near the mesh.