| 摘要 |
A scalable data acquisition system (SDAS) that may be used in connection with both single slice and multislice imaging systems is described. Generally, the SDAS in configured for use in a computed tomography system and converts the low level electrical current signal from the x-ray detector to digital values for image reconstruction, display and archive. The SDAS also includes an anti-alias filter for each cell prior to analog to digital conversion (ADC). More specifically, the analog current signals from the detector are supplied to the SDAS input channels via shielded ribbon or flex cables. The cables are connected to the SDAS at the SDAS backplane. The SDAS Converter boards are also plugged into the SDAS backplane. This interconnection provides several advantages. For example, the backplane enables ganging the detector cells on the outside edges of the fan beam. The backplane also allows a redistribution of the detector cells to appropriate converter boards. Signals from more than one slice are contained in the same flex cable, and each converter board only serves one slice since the reconfiguration of SDAS from one multi-slice configuration to another or to the single slice configuration requires only the removal or addition of converter boards. Also, the backplane enables a blending or weaving of SDAS channels and detector cells near the end channels of a converter board. Artifacts such as a band in the image are usually the result of common or uniform error source across one group of adjacent channels versus a neighboring group of channels. If all the channels on one converter board have a common error difference compared to a neighboring converter board, this type of image artifact is quite likely. By interweaving detector cell assignments versus converter card on the edges of the converter card, the susceptibility to a band artifact is reduced.
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