检测器模块精要.pptVIP

Data Acquisition system (DAS) of Competitive CT Philips and Neusoft Medical Systems Co.,Ltd Abstract The function of DAS: Measure the intensity of X-ray radiated from the tube and after though the patient’s body. Supply the additional information for image reconstruction. Flow of Signal Brief Introduction of the Main Part Detector: Convert the attenuated X-ray to current signal. DAS board: Convert the current signal from the detector to digital signal and store the DAS data temporarily. MONITOR: Convert the current signal from monitor detector to digital signal. Measure the intensity of X-ray before its attenuation; and measure the focus of tube’s swaying along Z-axis DAS Interface board: Transform the data from DAS-Board and monitor to set format; realize the communication between RCS and GCS. Important Concepts Channel: A dimensional concept. The minimal unit in dimension of DAS. There are 1440(720×2) channels in Competitive CT DAS. VIEW: A temporal concept, each acquisition process is called one view. Detail Information Detector Working Principle: When the tube works, X-ray radiated in the scintillator causes light which will be received by the photodiode. Then the photodiode can generate current signal under the effect of the light. The intensity of the outputted current signal and of the X-ray are in direct ratio. Function: Receive x-ray and convert it to current signal, and transfer this signal to DAS board. In Competitive CT, the detector module is connected with the DAS motherboard by flat cable. the DAS board is installed on the DAS motherboard. Structure: Each detector module consists of 16×2 channels. The DAS of Competitive CT include 45 detector modules, so there are 720×2=1440channels. Photodiode Sketch DAS Board Working Principle: Receive the current signal from detector and convert it to digital signal. The core element of DAS board is DDC112, Dual Current Input 20-Bit. DAS Board Sketch Brief Introduction of Functions DDC