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Contrast effects of a gadolinium filter
Author(s) -
Burgess A. E.
Publication year - 1981
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.594933
Subject(s) - gadolinium , contrast (vision) , materials science , imaging phantom , filter (signal processing) , optics , nuclear medicine , physics , medicine , computer science , metallurgy , computer vision
Several authors have suggested using heavy metal filters with K edges in the diagnostic energy range to reduce the width of the x‐ray spectrum and hence reduce patient radiation exposure. This spectral narrowing also increases subject contrast and permits an increase in tube potential. Results of contrast measurements are presented for a 250 μ gadolinium filter. It was found that aluminum filter contrast could be matched by using 8 to 10 kVp higher potential with the gadolinium filter. Similar results were found for calcium tungstate and rare‐earth screens. Measurements were also done to determine skin exposure and mAs ratios for both constant contrast and constant kVp technique conversion methods. A simple theory with one adjustable parameter gives a reasonable fit to the experimental results.