The invention relates generally to treatment of solid cancers. More particularly, a method and apparatus for efficient radiation dose delivery to a tumor is described. Preferably, radiation is delivered through an entry point into the tumor and Bragg peak energy is targeted to a distal or far side of the tumor from an ingress point. Delivering Bragg peak energy to the distal side of the tumor from the ingress point is repeated from multiple rotational directions. Beam intensity is proportional to radiation dose delivery efficiency. The multi-field irradiation process with energy levels targeting the far side of the tumor from each irradiation direction provides even and efficient charged particle radiation dose delivery to the tumor. Preferably, the charged particle therapy is timed to patient respiration via control of charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus.
