Patent US 5,081,660

An X-ray image pick-up method causes X-rays from an X-ray source to be irradiated on an object for picking up its image as passed through a filter capable of restricting any fluctuation of the effective X-ray energy within .+-.10%, and then the X-rays thus penetrated through the object to be picked up by an image pick-up means. Radiation dose with respect to the object and eventually to operators is thereby minimized, while the image pick-up can be realized with a high resolution.