| 摘要 |
An x-ray source for use in computerized tomographic applications focuses an electron beam on an arcuate anode ring to produce an x-ray beam which passes through a planar slice of the subject under study. Electromagnetic focusing and directing of the electron beam acts to produce the same effects as those produced by a single x-ray source which is mechanically rotated about the patient. Because it is very difficult to focus and to bend an electron beam having a cross section with other than cylindrical symmetry, and because it is highly desirable that the cross section of the electron beam have a rectangular cross section as it impinges upon the anode, an electromagnetic means is disposed adjacent the electron beam path between the anode and the beam bending coils to oscillatorily deflect the beam so that it effectively exhibits a substantially rectangular cross section, the long dimension of the rectangle always pointing toward the system axis. This configuration permits either a more intense x-ray source or, alternately, an x-ray source with a smaller projected spot size.
|
