抄録
We have calculated scatter to primary X-ray ratios at detector position in the cone-beam 3D X-ray CT scanner using the Monte Carlo simulation and evaluated the effects of scatter on reconstructed images. Without bow-tie filter, the intensity of scatter at detector center is twice as much as that of primary for water phantom of 11.5cm rasius, and the CT number of reconstructed image fall by about 30 % at center. With bow-tie filter, the scatter ratio to primary at center decrease largely and the CT number fall by about 10 % in the whole image. Furthermore, the usage of the filter decreases in absorbed dose of 60% compare with no usage of filter.
