The present invention includes new techniques for radiotherapy and other external electromagnetic influence of treatment subjects. In one aspect of the invention, a plurality of nano-scale or other small-scale machines is introduced to the blood stream (for example, by hypodermic injection). The design of each small-scale machine may include different sub-devices and electrostatic or magnetic charges, at different surface or internal locations. An electromagnetic and/or electrostatic control system the remotely alters the orientation and location of the small-scale machines, and applies the machines, and variably applies different sub-devices to different treatment targets. In some aspects, the sub-devices include actuable protection and sub-devices, to deliver drugs or other factors at specific locations commanded by the control system or a user.
