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Energy absorbed in calcium tungstate x‐ray screens
Author(s) -
Shuping Ralph E.,
Judy Philip F.
Publication year - 1977
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 - 10.1118/1.594373
Subject(s) - optics , absorbed dose , materials science , phosphor , range (aeronautics) , beam (structure) , tungsten , optical density , absorption (acoustics) , dosimetry , x ray , energy (signal processing) , computational physics , physics , optoelectronics , radiation , nuclear medicine , medicine , quantum mechanics , metallurgy , composite material
The energy which must be absorbed in a CaWO 4 x‐ray intensifying screen to produce unit net optical density on a film has been evaluated by measurement and calculation for a screen–film system over a range of beam qualities (1.4–7.4 mm Al HVL) spanning the diagnostic x‐ray region. It was found to be constant within experimental error. The absorbed‐energy constant for three additional CaWO 4 screens is presented for a single beam quality. To correct the estimation of absorbed energy, the fractional escape of tungsten K x rays has been evaluated and the results are presented as a function of phosphor loading. The absorbed‐energy constant is useful for predicting optical density for variable beam conditions; a family of characteristic curves based on exposure is reduced to one curve for a particular film–screen system, expressed as optical density as a function of absorbed energy.