Abstract
Systems and methods are disclosed for trapping or focusing magnetizable particles comprising therapeutic agents at a distance using a dynamic magnetic field and feedback control, to enable the treatment of diseased areas deep inside a patient's body. The methods may be used to diagnose or treat diseased areas deep within a patient, for example tumors of the lungs, intestines, and liver, and is also useful in enhancing the permeability of solid tumors to chemotherapeutic agents.