The invention comprises an X-ray tomography method and apparatus used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. In various embodiments, 3-D images are generated from a series of 2-D X-rays images; the X-ray source and detector are stationary while the patient rotates; the 2-D X-ray images are generated using an X-ray source proximate a charged particle beam in a charged particle cancer therapy system; and the X-ray tomography system uses an electron source having a geometry that enhances an electron source lifetime, where the electron source is used in generation of X-rays. The X-ray tomography system is optionally used in conjunction with systems used to both move and constrain movement of the patient, such as semi-vertical, sitting, or laying positioning systems. The X-ray images are optionally used in control of a charged particle cancer therapy system.