Apparatus for minimising the effect of concentrated high density material outside a small scan circle in computed tomography.

摘要

A method and apparatus for minimizing a streaking effect found in reconstructed images obtained from high resolution CT scanning of a small scan circle that corresponds to a limited region of interest, such as portions of the spinal cord of a patient, particularly in scans that include concentrated high density material, such as bone, situated outside the small scan circle. The approximate range of view angles that will project bone from outside the limited region of interest is determined. Detectors corresponding to the determined region are selected out. The projection data acquired by the selected detectors is filtered. The filtering is accomplished by convolving the projection data with a preselected filter function or in machine implemented form by passing the electrical signal representing the projection data through a low pass filter.