<p>Disclosed is a low cost computer tomographic (CT) scanner system specifically designed for radiation therapy treatment planning. A 512-channel photo-diode array with digitizing electronics converts image intensifier optical projection data directly into digital signals and has a dynamic range on the order of 100,000:1. The new simulator includes a rotating gantry, an X-ray generator with radiographic and fluoroscopic modes and a therapy style patient support assembly. Results on head and body size phantoms indicate that the simulator X-ray generator and image intensifier tube (IIT) with multi-channel photo-detector can produce photon statistic limited CT images. Software and hardware compensation methods are described which minimize geometrical distortions. Low noise, high input impedance electronics are employed which are phase-locked to the line frequency. A dual sample interval method is employed which effectively increases the range of the digital signal produced by the front-end electronics by three additional bits.</p>
申请公布号
DE69129008(T2)
申请公布日期
1998.08.20
申请号
DE1991629008T
申请日期
1991.07.02
申请人
VARIAN ASSOCIATES, INC., PALO ALTO, CALIF., US
发明人
SEPPI, EDWARD, J., PORTOLA VALLEY, CA 94028, US;SHAPIRO, EDWARD, G., MOUNTAIN VIEW, CA 94043, US;ANDERSON, ROBERT, L., PALO ALTO, CA 94306, US