EVALUATING PHANTOM OF CT APPARATUS AND EVALUATING METHOD USING THIS AND METHOD OF MANUFACTURING EVALUATING PHANTOM

摘要

PROBLEM TO BE SOLVED: To accurately evaluate spatial resolution of a cross-sectional image obtained by a high resolution type CT apparatus. SOLUTION: A copper film 3 and a polyethylene film 4 different in an absorbing factor of a radioactive ray and thinly workable in a thickness are alternately laminated on a side surface of a columnar material 2 to constitute an evaluating phantom 1, a cross-sectional image is photographed by using the CT apparatus on a cross section of the evaluating phantom 1 almost vertical to the axis of the columnar material 2, and a layer of a stripe-shaped film on the cross-sectional image is observed to evaluate spatial resolution of the cross-sectional image. The spatial resolution can be more accurately evaluated by measuring MTF by using a difference in contrast between two kinds of films in the cross- sectional image.