1. A medical image diagnosis apparatus configured to emit radiation to a breast as a subject, detect radiation that has passed through the subject, and generate three-dimensional image data including a plurality of tomographic images of the subject, the medical image diagnosis apparatus comprising: an image generator configured to project the three-dimensional image data in a predetermined direction to generate a two-dimensional image; a setting unit configured to set a region of interest in the two-dimensional image; an image detector configured to detect, based on the region of interest and a corresponding region that corresponds to the region of interest in each of the tomographic images, a tomographic image including the corresponding region that is similar in pixel value to the region of interest from the three-dimensional image data; and a display controller configured to display the tomographic image detected by the image detector on a display unit.