High-speed cone-beam reconstruction: an embedded systems approach

摘要

Cone-beam reconstruction (CBR) is growing in importance, but current computer systems are slower than desirable for clinical use. We have built a high-speed system for high-quality, 3-D imaging. We partitioned the problem into input, filtering, backprojection, postprocessing, and output components. We mapped most of the components to standard RACE++ processing nodes. The backprojection component is very compute-intensive; we mapped it to a field-programmable gate array (FPGA)-based adjunct processor. We built a prototype FPGA card, optimized for flexibility, and implemented the backprojection in that FPGA. This strategy allows for redesigning the backprojection function when necessary, and keeps the other details of the CBR algorithm in easily programmable processors. We present a system that performs Feldkamp CBR of 300 projections into a 512 cubical image in 38.7 seconds. The system is designed to be scalable, so that Feldkamp CBR of 21.4 seconds can be performed with two adjunct processors, and Feldkamp CBR of other regions of interest or dimensions could be performed in proportionately shorter times. Further optimization and faster-processing parts will also contribute to continual speed improvements. This system is flexible and can be extended to perform other imaging functions, such as real-time planar angiography, with the same hardware.