Abstract
New method is proposed for the measurement of the CT slice thickness. This method is to measure the CT number of a traveling material, placed perpendicularly to the slice plane, as a function of the traveling distance. Movement of the rod was controlled using a traveling microscope with an accuracy of 0.5 mm, The rod was inserted from the outside to the inside of the scan plane. CT number of the imaged rod increases gradually, initially from the air CT number, finally to the genuine CT number of the rod. Full slice width is evaluated as the difference of moving distances. As the rod is projected in a parallel way with the detector aperture, the partial volume effect due to the aperture size is no problem. This method provides a direct and accurate estimate of slice thickness. Comparative study has been made with the 45 degree aluminium strip method.
