FIG. 1.

Conceptual schematic of the FLASH experimental X-ray small animal conformal therapy (FLASH-EXACT) system currently being developed. A next-generation compact electron linac produces a high current (1.5 mA average), 10 MeV beam that generates X rays through bremsstrahlung for FLASH dose rates exceeding 50 Gy/s at 20–25 cm from the X-ray source. The collimated X-ray beam is directed toward the mouse target at the isocenter. The mouse is immobilized securely within a body weight-specific conforming mold, and rotated relative to a kV X-ray source/detector combination for CT imaging, and the 10 MV X-ray treatment beam for conformal arc irradiation, both of which are stationary and share a common isocenter.