Research On CT High-speed Data Transmission Technology And Its Application

CT images have high accuracy and good resolution.Therefore,CT imaging equipment has become one of the most widely used detection devices in diagnostic imaging.It is widely used in the preoperative diagnostic analysis,lesion location,and many routine screenings.The CT slip ring is one of the key components of the CT imaging device and is used for power and data transmission between the CT rotating end and the fixed end.With the continuous upgrading of CT equipment,the number of detectors in CT equipment is increasing,the amount of data collected by DAS is also increasing,and the number of layers of DAS is also getting higher and higher.The transmission rate of the ring data transmission system has also raised higher and higher requirements.At present,China's CT data transmission technology has serious shortages and deficiencies,which seriously restricts the healthy development of China-made medical CT imaging equipment.Therefore,the CT high-speed data transmission technology has important theoretical research significance and engineering application value:?1?Through the analysis and summary of the data transmission technology between the relevant non-contact rotating body,we can find out its shortcomings and propose an improvement.Then,the CT high-speed data transmission technology is conducive to promoting the technical progress and development of the CT slip ring industry;?2?The application research of the proposed CT high-speed data transmission technology can prompt the technology to realize engineering application as soon as possible,so as to be able to external CT manufacturers provide more CT data transmission solutions,reduce the price of CT slip rings and promote the healthy development of the entire CT equipment industry;?3?The CT data transmission technology developed has independent intellectual property rights and can fill in the field in Chinese technology gap,at the same time,through the technical cooperation with the domestic electric slip ring manufacturers,we can develop the CT slip ring products with independent intellectual property rights,to fill the gap in China's CT slip ring products,promoting the price of CT slip ring products to reduce,save CT equipment development costs and use costs,ultimately benefit the majority of domestic and foreign consumers.This dissertation will focus on the corresponding systematic research on some key technologies in optical fiber transmission and spatial optical transmission in the communication link of non-contact rotating high-speed data transmission system.First of all,through a large number of domestic and foreign literature research and patent analysis,in light of the deficiencies of current non-contact high-speed rotating data transmission technologies or patent barriers,the overall solution for non-contact rotating high-speed data transmission systems with independent intellectual property rights has been determined.Radial type optical path single-wavelength?1550nm?light transmission technology combines optical fiber communication with free space optical communication to achieve high-speed data transmission from the rotating end to the fixed end,thus conquering the large-diameter hollow slip of domestic slip ring manufacturers.High-speed data transmission in the ring of key technical solutions,the current research work in this paper has been applied for five invention patents,of which three have been authorized.At the same time,the off-axis spatial light folding technology studied was tested.The results show that,during the continuous rotation of the CT turntable,the light detector can always detect the optical signals transmitted by the respective fiber collimators,and the eye traces are clear.The eye pattern is relatively correct,the eye-crossing ratio is 50%,and the bit error rate?BER?is better than 10^-12?data transmission rate 10 Gbps,test time 300 second,BER confidence 95%?,therefore,the off-axis spatial light folding technology studied satisfies the requirements for use.Secondly,in the optical signal transmission system in this paper,in order to reduce the alignment accuracy between the exit spot and the optical receiver,it is easy to reduce the difficulty of engineering implementation,and the beam spot of the fiber collimator needs to be appropriately expanded.Based on the actual requirements of this thesis,Galileo-type beam-expanding structure mode was chosen,and Zemax software was used to perform optical design and simulation of the beam expander system.The beam expander system uses three spherical mirrors.The results show that the beam expander system reaches 10X.The spot diameter of the exit spot of the 1550nm laser was changed from 0.7mm to 7mm.The beam expansion requirements and the aberrations of the beam expansion system have also been well controlled,meeting the beam expansion requirements of the subject optical transmission system.Next,on the basis of the existing laser shaping theory,combined with the special requirements of the laser shaping structure of this paper,and using the improved laser technology of the compound eye lens,the Gaussian beam has become a flat-top beam with a wavelength of 1550 nm and a spot diameter of 7 mm.The uniformity of the spot on the light receiving surface at a distance of 425 mm from the light exit surface has reached 85%,which satisfies the design requirements of the CT high-speed data transmission system.Subsequently,in order to meet the requirements of equal optical path design,the equal length detection technology for optical transmission links was studied.Aiming at the shortage and inconvenience of multi-channel high-speed data transmission synchronization detection technology,a new multi-channel data transmission link isometric detection technology based on phase method laser ranging technology is designed,and the relevant theoretical calculation and experimental verification are performed.The maximum relative optical path difference of the optical communication links in the high-speed data transmission process of 10 Gbps in the static state of the thesis is 0.9 mm,which is less than the maximum allowable optical path difference?3mm?.At the same time,it is verified that the BER of the optical communication system in the static optical communication system during the transmission of 10Gbps data is better than 10^-12?test time 300 second,BER confidence 95%?,that is,the designed optical communication system meets 10Gbps high speed.The technical requirements for data transmission also verify that the optical link isometric testing technology developed in this paper is reasonable and feasible.Related technologies have applied for an invention patent,and the project is in the stage of substantive examination.At the same time,an SCI paper has been published based on the technology and method.For details,see the first article in the list of the papers that have been published in the last part of the paper.Afterwards,applied research on the CT high-speed data transmission technology researched in this dissertation is to study and design the opto-mechanical structure of the adaptable CT scanner and form the prototype of the CT high-speed data transmission system so that the technology can be applied successfully.Lay the foundation for the actual project.An opto-mechanical structure system adapted to a high-speed data transmission smooth ring system was designed by using a systematic scheme design method.A three-dimensional solid design software Solid Works was used to perform 3D solid modeling.The model was then simplified and processed into a large CAE analysis software.ANSYS Workbench performed static analysis on it.The analysis structure showed that the optimized spare parts of several components independently designed at the rotating end of the optomechanical structure of the developed CT high-speed data transmission system were limited,in order to reduce the quality of the entire light machine structure,and it was convenient.The overall movement and adjustment of the machine,the design of the top end of the support arm and cushion corner column topology optimization design,its quality was reduced by21.45%and 30.51%,to reduce the prototype quality,beautify the purpose of the prototype structure.Then,the harmonic response vibration at different modal frequencies during the normal operation of the high-speed data transmission system was analyzed and evaluated.The maximum resonance generated during the normal operation of the designed structure was determined.CT high-speed data transmission system data transmission stability and accuracy have an impact.Finally,the BER test of the CT high-speed data transmission technology test prototype developed in this thesis is performed.The BER test is an effective method to verify the data transmission performance.Therefore,the overall performance of the CT high-speed data transmission technology prototype can be tested by the BER test.The experimental results show that when the output optical power value of the EDFA module takes 33dbm,the frequency and duty ratio of the carrier signal output by the FPGA module are taken as 200MHz and 50%respectively,the experimental data transmission of the experimental high-speed CT data transmission prototype is best.When the best position and optical communication module parameters are set in each mechanical adjustment module,the data transmission rate is 2.5Gbps and the rotation speed is 120rpm,the BER of the CT high-speed data transmission technology prototype is better than 10^-12?test time 1200s,BER confidence 95%?,which meeting the technical requirements of the Suzhou Science and Technology Plan project;However,when the speed is 150rpm,the data rate is 10Gbps,the BER is 10^-3?test time 300s,BER confidence 95%?,there is a certain gap between the technical requirements and the national key R&D project.In conclusion,the theoretical and practical aspects of the CT high-speed data transmission technology studied in this paper are feasible,and can achieve high-speed data transmission between the rotating end and the fixed end of the CT system.Currently,the developed experimental prototype of CT high-speed data transmission technology can achieve CT data transmission of no more than 2.5Gbps,and further research is needed to achieve non-contact transmission of higher-rate data in the rotating state.