Aspects of the invention relate to radiotherapy methods and devices that use local field enhancements induced by metal particles in order to irradiate a target volume with a lower intensity as compared to conventional treatment methods. The metal particles may be coupled to vehicles and administered to a patients body. As vehicles may have a higher affinity to the target volume than to the rest of the body, metal particles may concentrate within the target volume. When in irradiating the target volume, the metal particles cause local field enhancements of the treatment radiation, thus allowing irradiating the body with a lower overall intensity. Local field enhancements may be determined and used to control a radiation therapy device.
