An external immobilizer for cancer treatment has a plurality of inflatable bladders that are independent finable depending on computer instruction based on patient position data provided from integrated or separate position determining means, such as external cameras or sensors, optionally with internal and/or external markers. In preferred embodiments, the immobilizer is fully integrated with an imaging means as well as the external beam radiation source, thus allowing both real time, independent anatomical compensation or correction for patient movement and fine control of beam shape and position to accurately target the tumor, even if the patient moves.