Clinical experience with a new developed whole body CT-scanner (Dynamic Scanner)

Employing an x-ray generator based on scanning electron microscope principles, a new CT-scanner was developed. Early clinical experience with this scanner is discussed, and several normal and pathological scans are presented. This scanner was named the ''Jeol Dynamic Scanner'', and it has quite a unique structural system. The electron beam is generated from an electron gun and is focused by an electron-optical lens. The beam is accelerated and projected onto a plane anode target by electromagnetically deflection at a high speed and with great accuracy. High-intensity x-rays generated from the target pass through a pin hole and form an x-ray microbeam which scans a cross-section of the patient's body. The x-ray generator and the detector are rotated around the imaging chamber by means of a digital servo-drive system. The detector only catches the beam intensity, without any position information, since the irradiated position of the electron beam on the target is prearranged by the computer. This scanner has the following features. 1) A whole-body scanner with a scanning time of 5 sec/slice. 2) According to the size of an object, the width of the x-ray beam and the scanning area can be controlled so as to get a high-resolution image. 3) The system, with its high detection efficiency of x-ray photons, makes low-dosage CT-imaging possible. 4) It allows the taking of a plain x-ray scanning image which can identify the portion of the patient's body for which CT-scanning is requested. (author)