PROBLEM TO BE SOLVED: To provide a noise suppression processor which performs noise suppression processing without destroying a faint shadow such as mammary glands appearing a radiation image capturing a breast, a method, and a program.SOLUTION: A breast composition information acquisition section 84 acquires a mammary gland content rate for each unit pixel of a breast area of a radiation image P acquired by irradiating a breast M of a subject with radiation rays. A noise suppression section 86 acquires an index value indicating the size of a range where pixel values are dispersed at each unit pixel position from the mammary gland content rate of the unit pixel, performs noise suppression processing in which the smaller the index value is, the lower level of the noise suppression is set at a position of a target pixel, while performing noise suppression processing in which the larger the index value is, the higher the level of the noise suppression is set at the position of the target pixel.SELECTED DRAWING: Figure 4【課題】乳房を撮影した放射線画像に現れる乳腺のような淡い陰影を潰すことなくノイズ抑制処理を行うノイズ抑制処理装置および方法並びにプログラムを提供する。【解決手段】乳房組成情報取得部８４で、被写体の乳房Ｍに放射線を照射して得られた放射線画像Ｐの乳房領域の各単位画素ごとに乳腺含有率を取得する。ノイズ抑制部８６で、単位画素の乳腺含有率から、各単位画素位置で、画素値が分散する範囲の大きさを表す指標値を取得して、指標値が小さいほど注目画素の位置でノイズ抑制の程度を小さくしたノイズ抑制処理を施し、指標値が大きいほど注目画素の位置でノイズ抑制の程度を大きくしたノイズ抑制処理を施す。【選択図】図４
