The present invention is a method and system for computed tomography imaging. The tubular body includes an open base end and an open top end. The trace-detecting unit further has at least a light source and a sensor. m, said silica fume representing at most 15 parts by weight per 100 parts of cement; an antifoaming agent; water-reducing superplasticiser; optionally fibers; and water. Each of the storage units stores a count value obtained by the counter in accordance with a comparison result of the comparator, the count value corresponding to an elapsed time until the voltage of the slope signal is changed from the initial voltage to a voltage coinciding with the pixel signal. The connection terminal and the wiring are covered by an interlayer insulating film, and an opening is provided in a portion corresponding to the connection terminal.