Patent Number: 
Section: claims

1. A method comprising:receiving a first instruction to enter an imaging mode;in response to the first instruction, automatically reducing a focal spot size of a radiation beam, moving a flattening filter out of a path of the radiation beam, moving a first target for photon emission out of the path of the radiation beam and moving a second target for photon emission into the path of the radiation beam, and moving a scatter-reducing filter into the path of the radiation beam;receiving a second instruction to enter a first radiation treatment mode; andin response to the second instruction, automatically increasing a focal spot size of the radiation beam, moving the flattening filter into the path of the radiation beam, moving the second target out of the path of the radiation beam and moving the first target into the path of the radiation beam, and moving the scatter-reducing filter out of the path of the radiation beam. 2. A method according to claim 1, wherein the second instruction comprises an instruction to enter a photon radiation treatment mode, and further comprising:receiving a third instruction to enter an electron radiation treatment mode; andin response to the third instruction, automatically moving the first target out of the path of the radiation beam so that neither the first target or the second target is in the path of the radiation beam. 3. A method according to claim 1, wherein reducing the focal spot size of the radiation beam comprises energizing deflector plates disposed adjacent to the path of the radiation beam to focus the radiation beam. 4. A method according to claim 1, wherein an atomic weight of the second target is less than an atomic weight of the first target. 5. A method according to claim 1, wherein, for a given incident electron beam, photons emitted by the second target exhibit a lower average energy than photons emitted by the first target. 6. A method according to claim 1, further comprising:presenting an interface to receive the first instruction and the second instruction. 7. A method according to claim 1, further comprising:in response to the first instruction, automatically changing dosimetric characteristics of the radiation beam. 8. An apparatus comprising:an input device to receive a first instruction to enter an imaging mode, and a second instruction to enter a first radiation treatment mode;an accelerator waveguide to emit a radiation beam;a first device to reduce a focal spot size of a radiation beam in response to the first instruction, and to increase a focal spot size of the radiation beam in response to the second instruction;a second device to move a flattening filter out of a path of the radiation beam in response to the first instruction, and to move the flattening filter into the path of the radiation beam in response to the second instruction;a third device to move a first target for photon emission out of the path of the radiation beam and to move a second target for photon emission into the path of the radiation beam in response to the first instruction, and to move the second target out of the path of the radiation beam and to move the first target into the path of the radiation beam in response to the second instruction; anda fourth device to move a scatter-reducing filter into the path of the radiation beam in response to the first instruction, and to move the scatter-reducing filter out of the path of the radiation beam in response to the second instruction. 9. An apparatus according to claim 8, the first device comprising:deflector plates disposed adjacent to the path of the radiation beam. 10. An apparatus according to claim 8, wherein an atomic weight of the second target is less than an atomic weight of the first target. 11. An apparatus according to claim 8, wherein, for a given incident electron beam, photons emitted by the second target exhibit a lower average energy than photons emitted by the first target. 12. An apparatus according to claim 8, further comprising:a fifth device to change dosimetric characteristics of the radiation beam in response to the first instruction. 13. A medium storing program code, the program code comprising:code to receive a first instruction to enter an imaging mode;code to, in response to the first instruction, automatically reduce a focal spot size of a radiation beam, move a flattening filter out of a path of the radiation beam, move a first target for photon emission out of the path of the radiation beam and move a second target for photon emission into the path of the radiation beam, and move a scatter-reducing filter into the path of the radiation beam;code to receive a second instruction to enter a first radiation treatment mode; andcode to, in response to the second instruction, automatically perform at least one of: increase a focal spot size of the radiation beam, move the flattening filter into the path of the radiation beam, move the second target out of the path of the radiation beam and move the first target into the path of the radiation beam, and move the scatter-reducing filter out of the path of the radiation beam. 14. A medium according to claim 13. wherein the second instruction comprises an instruction to enter a photon radiation treatment mode, and the program code further comprising:code to receive a third instruction to enter an electron radiation treatment mode; andcode to, in response to the third instruction, automatically move the first target out of the path of the radiation beam so that neither the first target or the second target is in the path of the radiation beam. 15. A medium according to claim 13, wherein the code to reduce the focal spot size of the radiation beam comprises code to energize deflector plates disposed adjacent to the path of the radiation beam to focus the radiation beam. 16. A medium according to claim 13, wherein an atomic weight of the second target is less than an atomic weight of the first target. 17. A medium according to claim 13, wherein, for a given incident electron beam, photons emitted by the second target exhibit a lower average energy than photons emitted by the first target. 18. A medium according to claim 13, the program code further comprising:code to present an interface to receive the first instruction and the second instruction. 19. A medium according to claim 13, the program code further comprising:code to, in response to the first instruction, automatically change dosimetric characteristics of the radiation beam.