ELECTRON ACCELERATOR AND RADIOTHERAPY APPARATUS USING SAME

摘要

A small-sized lightweight electron accelerator (2, 40, 60) providing a strong electron beam and using fixed-field strong focusing, comprising a vacuum vessel (10), an electromagnet (20) disposed in the vacuum vessel (10), an electron beam injecting unit (11) for injecting an electron beam into the vacuum vessel (10), an accelerator (13) for accelerating the electron beam, and an electron beam transporting unit (26) for transporting the accelerated electron beam from the vacuum vessel (10). The electromagnet (20) is a strong-focusing electromagnet composed of a focusing electromagnet (21) and diverging electromagnets (22) disposed on both sides of the focusing electromagnet (21), or composed of a focusing electromagnet (21) and diverging units disposed on both sides of the focusing electromagnet (21). An inner target (25) for generating X-ray radiation is disposed in the vacuum vessel (10) immediately in front of the electron beam transporting unit (26) so as to selectively take out the accelerated beam and the X-ray radiation. Thus an electron beam of 1 to 10 mA that is 10 or more times that of conventional electron beam accelerators can be produced with an accelerating voltage of 10 MeV. Consequently a radiotherapy apparatus (1) capable of applying an electron beam to a tumor tissue in a short time that is 1/10 or less of conventional ones.