156 results about "X ray attenuation" patented technology

System and method for XRD-based false alarm resolution in computed tomography (“CT”) threat detection systems. Following a scan of an object with a megavoltage CT-based threat detection system, a suspicious area in the object is identified. The three dimensional position of the suspicious area is used to determine a ray path for the XRD-based threat detection system that provides minimal X-ray attenuation. The object is then positioned for XRD scanning of the suspicious area along this determined ray path. The XRD-based threat detection system is configured to detect high density metals (“HDMs) as well as shielded Special Nuclear Materials (“SNMs”) based on cubic or non-cubic diffraction profiles.

A novel process is for making ceramic based radiopac materials useful for X-ray radiation attenuation. The process is lead as well as rare earth free and thus obviates (i) the use of conventionally used lead metal and its compounds—which are toxic in nature and are heavy weight as the density of lead is 11.34 gm / cm-2. Further the low melting points of lead (325° C.) prohibits its use in high temperature shielding structures and (ii) the use of Rare earth is restricted because they are very costly and scarcely available. The novel process of the present invention utilizes different varieties of waste as raw materials such as fly ash (from thermal power plants), Red mud (from aluminum production), Rice husk silica (an agro waste) and pyrophyllite (an underutilized clay mineral). These waste materials contain various necessary constituents required for making radiopac materials namely silicon, titanium, iron and aluminum. The presence of different mineralizers in the raw materials used and use of phosphatic binders significantly helps in obtaining the radiopac materials, at relatively low temperature of 920° C. itself and thus leads to saving of considerable heat energy. Further as the waste are generated in powder form, the use of these waste also helps in saving on the account of grinding energy. The radiopac materials obtained by the novel process of present invention are capable of withstanding ambient to high temperature and thus finds wide applications in making aprons, gloves and ceramic tiles, bricks for attenuation of X-ray radiations. The radiopac materials are useful as materials for construction of partition wall of X-ray room in hospitals, research institutes and industries. Apart from this radiopac materials an also be used and in making high temperature X-ray attenuation structures.

The invention relates to a method and a device for automatically differentiating bones or other calcium-containing materials and contrast agent in soft tissue of an object area. In at least one embodiment of the method, two image data records of two computed tomography pictures of the object are provided that have been recorded in the context of a different spectral distribution of the X-radiation. For voxels of at least one interesting slice, there is calculated from the two image data records a ratio r that is yielded from measured or averaged X-ray attenuation values of the respective voxel or its environment in the context of the different spectral distributions of the X-radiation and prescribed X-ray attenuation values of soft tissue in the context of the different spectral distributions of the X-radiation according to a prescribed calculation rule. Upon overshooting of a threshold value for the ratio r the respective voxel is assigned either contrast agent or calcium-containing material as a function of the magnitude of r. The proposed method and / or the associated device enable a reliable automatic differentiation of bones or other calcium-containing materials and contrast agent in computed tomography pictures.