A fundamental radiologic principle is that patient dose can be reduced with x-ray beam hardening [1,2], which can be achieved by increasing tube voltage and/or beam filtration [3,4]. Unfortunately, tube voltage augmentation and beam filtration both diminish subject contrast. Although subject contrast can be partly recovered with image processing techniques after digital image acquisition, these manipulations can increase the apparent image noise. Thus, despite the adoption of digital technology by many imaging centers, a common strategy still is to simultaneously add beam filtration and reduce...

Study concept:Extremities of a cadaver, not preserved in formaldehyde, were selected as radiographic imaging objects, in particular the hand, wrist, forearm, foot, ankle and the tibia/fibula. The cadaver was supplied by the Department of Forensic Medicine at the Frankfurt University Hospital.Image acquisition:Study objects were imaged in two standard projections using stepwise decreasing dose levels and variation of added filtration (no filtration, 1.0 mm aluminum, 1.0 mm aluminium + 0.1 mm copper) under digital projection radiography. The initial dose level for all body parts imaged was...

Dosimetry:Using the 1-mm-thick aluminum filter, mean entrance skin dose in all images was 5.9% less (dose level 100%), 11.2% less (dose level 75%), 2.6% less (dose level 50%) and 12.9% less (dose level 25%) than without added filtration. Integration of a 1-mm-thick aluminum filter in combination with a 0.1-mm-thick copper filter led to a still larger decrease of mean entrance skin dose compared to the images obtained without any added filtration, in detail: 26.9% (dose level 100%), 21.1% (dose level 75%), 25.7% (dose level 50%)...

It is possible, in the case of extremities, to lower mAs to 75 % of the normal value, a reduction of ca. 25% in dose, under simultaneous use of added aluminum or aluminum/copper filtration, without compromising diagnostic value.

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T. Lehnert, M. Kissner, H. Korkusuz, U. Voigt-Koop, M.G. Mack, T.J. VoglDepartment of Diagnostic and Interventional RadiologyClinic of Johann Wolfgang Goethe University, Frankfurt/Main, GermanyEmail contact: [email protected]