Radiographic method and apparatus for reducing the effects of scatter in the image

A radiographic method for irradiating an object with a conical radiation beam and for obtaining a two-dimensional transmitted image of the object based upon a beam transmitted through the object, comprising:

• arranging radiation shielding means;
• irradiating said object with radiation beams from different positions;
• allowing the shielding means to pass to an image converter some of transmitted primary radiation beams not scattered by but transmitted through the object and some of scattered radiation beams scattered by the object so as to obtain, in a form of electrical signals, a first radiation image of the object when the object is irradiated from at least one of the positions, and allowing the radiation shielding means to shield the transmitted primary radiation beams and to pass to the image converter some of the scattered radiation beams so as to obtain, in the form of electrical signals, a second radiation image of the object when the object is irradiated from at least one of the positions;
• and
• obtaining the two-dimensional transmitted image of the object by electrically processing the first and second radiation images obtained in the image forming step, the two-dimensional transmitted image being substantially free from the influence of spatial modulation caused by the radiation shielding means, and substantially free from the influence of the scattered radiation beams.

A radiographic apparatus for irradiating an object with a conical radiation beam and for obtaining a two-dimensional transmitted image of the object based upon a beam transmitted through the object, comprising:

• irradiating means for irradiating the object with primary radiation beams of conical shape from a radiation source at least two times while the object is at a position with respect to the radiation source;
• first and second shielding means arranged in a primary radiation beam passing region and being movable between first and second states, the first and second shielding means passing both some of transmitted primary radiation beams transmitted through the object and some of scattered radiation beams scattered by the object when the first and second shielding means are in the first state, the first and second shielding means shielding the transmitted primary radiation beams and passing some of the scattered radiation beams when the first and second shielding means are in the second state;
• an image converter arranged on an opposite side of said first and second shielding means from the radiation source and having a screen opposing the object, the image converter receiving a first radiation image on the screen and converting the first radiation image into a first converted image when the first and second shielding means are in the first state, and the image converter receiving a second radiation image on the screen and converting the second radiation image into a second converted image when the first and second shielding means are in the second state;
• imaging means, arranged to oppose the first and second converted images of the image converter, for converting the first and second converted images of the first and second radiation images into electrical signals to obtain image data;
• and
• reproduction/display means, electrically coupled to the imaging device, for storing the image data of the first and second radiation images and electrically processing the image data of the first radiation image, and for reproducing and displaying the two-dimensional transmitted image of the object which is substantially uninfluenced by the scattered radiation beams.

A radiographic apparatus for irradiating an object with a conical radiation beam and for obtaining a two-dimensional transmitted image of the object based upon a beam transmitted through the object, comprising:

• irradiating means for irradiating the object from first and second positions;
• radiation shielding means, arranged in a primary radiation beam passing region, for passing some of transmitted primary radiation beams and some of scattered radiation beams when the irradiating means irradiates from the first position, and for shielding the transmitted primary radiation beams transmitted through the object while passing some of the scattered radiation beams scattered by the object when the irradiating means irradiates from the second position;
• an image converter arranged on an opposite side of shielding means from the irradiating means and having a screen facing the object, the image converter receiving a first radiation image on the screen and converting the first radiation image into a first converted image when the irradiating means irradiates the object from the first position, and the image converter receiving a second radiation image on the screen and converting the second radiation image into a second converted image when the irradiating means irradiates the object from the the second position;
• imaging means, arranged to oppose the first and second converted images of the image converter, for converting the first and second converted images into electrical signals, thereby obtaining image data;
• and
• reproduction/display means, electrically coupled to the imaging means, for storing the image data of the first and second radiation images, and for electrically processing the image data of the first radiation image, to produce and display a two-dimensional transmitted image of the object which is substantially free from the influence of the scattered radiation beams.