Direct radiographic magnification as a means of complementing diagnostic imaging is not a new concept.1 The technique has been used widely, but never applied generally because a "bigger" image was not necessarily a "better" image. The physics of direct roentgenographic imaging is a complex marriage of x-ray beam geometry and the physicochemistry of photon absorption within a cassette.
Until the time of development of the Radiological Sciences Inc (RSI) x-ray tube, virtually all medical x-ray tubes depended on a hot tungsten filament as the initial source of electrons for the generation of x-ray photons (ie, since 1913, when Coolidge2 introduced the first filament x-ray tube). Detail in magnification is adversely affected by imperfections in the beam source. The standard filament x-ray tubes usually produce two point sources and a trailing edge of radiation off their axes. The resultant images are blurred, and this blurring is amplified by magnification. Therefore, the
X-ray AP, BRODEUR AE, SILBERSTEIN MJ, GRAVISS ER. The Many Advantages of Direct Microfocus Roentgenographic Magnification in Pediatric Radiology. Am J Dis Child. 1980;134(3):245–247. doi:10.1001/archpedi.1980.02130150003001
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