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H Vrooman

Publications and source records attributed to H Vrooman.

2 recordsLinked to original sources
PubMed1994

Scanning equalization mammography: preliminary evaluation.

The authors show preliminary work with an experimental scanning equalization mammography system intended to increase contrast and achieve adequate dose throughout the breast. The unit uses a modulated, segmented fan beam. Tests with and without scanning equalization were performed with contrast-latitude phantoms and a breast specimen with superimposed microcalcifications. Films of varying contrast were evaluated. Contrast at low and very high object densities was greatly improved with the equalization technique. Microcalcifications were better appreciated, especially in those regions of the specimen that were outside the optimal optical density range of the conventional technique.

Female↗
PubMed1993

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography. Preliminary evaluation.

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: the SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique.

Adult↗