According to one embodiment, an image processing apparatus includes a storage, a calculation unit, a generation unit and a display. The storage stores data relating to an X-ray image. The calculation unit calculates a first noise quantity of the X-ray image. The generation unit obtains a first X-ray dose corresponding to a first noise image represented by the first noise quantity based on relationship of an X-ray dose and a noise quantity, and calculates at least one second noise image corresponding to a second X-ray dose different from the first X-ray dose, and generates at least one simulated image by adding the second noise image to the X-ray image. The display displays the X-ray image and the simulated image.
