Silver News
Silver X-Rays Outshine Digital Images for Health and Safety Applications
By Samuel Etris, Senior Technical Consultant to the Silver Institute.
Despite inroads made by digital imaging technology, silverbased film used in X-Rays continue to offer images with more detail and clarity. Now, new films entering the market offer even greater advantages not only for medical use but for a wide range of industrial and security applications as well.
For example, Eastman Kodak Co. has introduced a greater light-capturing surface area for its widely-used tabular silver halide grains, doubling the film speed and increasing its definition. AGFA Gevaert produces an extremely narrow grain size distribution which avoids uneven density of details in the image, and Fuji and Konica have likewise contributed to other advances in film performance.
These new advances have increased the usefulness of silver-based radiographic film for inspection of locations that cannot be reached by digital systems. Image definition has
improved as well. These factors have resulted in increased use, and radiography is the largest user of silver in the photographic sector.
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Radiography is an important data gathering technique because it is nondestructive. For example, without X-Rays, doctors might have to perform surgical biopsies, and quality
control professionals would have to cut open building walls to check structure integrity.
In health care, silver film possesses two advantages over digital recording. First, its very wide density range provides superior detailed images, especially the fine detail needed for images of the lungs and mammary glands. Second, the film is readily portable for field use.
In industry, the high image detail provided by silver-based radiographic film helps to discover manufacturing flaws and errors after a product is in use. For example, the fine grain
images are essential in the inspection of rotating and nonrotating turbine buckets or blades for aircraft jet engines. Radiographic inspection of jet engine components by such manufacturers as GE Aircraft
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Engine Group, the Pratt Whitney Corp., and Rolls Royce Corp is also an
integral step in assembly. Subcontracting firms also are required under FAA rules to conduct radiographic
inspection of repaired or reconditioned components.
Building inspection requires special flexibility in placing radiographic film to determine the position of steel reinforcement bars within the concrete and to discover if the bars have been broken or bent. With the portable convenience of silver-based radiographic film, checking of welded beams in buildings, weld points of ships, integrity of welded railroad rails and other structures offers a simple test to allay the possibility of failure.
In the field of electronics, radiography is used for quality control of components, such as the misplacement of microcircuit transistors, the presence of ‘voids’ in multi-circuit computer cable, and the location of short circuits caused by solder spreading during electronic circuit board manufacture.
Silver News - Third Quarter 2004
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