Intra-individual comparison of average glandular dose of two digital mammography units using different anode/filter combinations.
OBJECTIVE
The aim of this study was to compare average glandular dose (AGD) in two full-field digital mammography units using different anode/filter combinations.


METHODS
Mammographies of 50 consecutive patients on a mammography system using a tungsten/rhodium (W/Rh) anode/filter combination were retrospectively compared to prior examinations on a different mammography unit using combinations of Molybdenum (Mo) and Rhodium (Rh). To exclude effects of increasing patient age, two prior examinations within 5 years were used. Both views of one breast were chosen for analysis. AGD was recorded as stated by each mammography unit. Accuracy of stated AGD and contrast-detail resolution were assessed using different breast phantoms.


RESULTS
The mean AGDs from the examinations using W/Rh were 0.95 mGy and 1.01 mGy for craniocaudal (CC) and mediolateral oblique (MLO) views compared to 1.51 mGy and 1.54 mGy, respectively, using combinations of Mo and Rh (P < .001). Relative reduction of AGD was independent of breast thickness but decreased with increasing breast density (partial correlation coefficient of 0.46, P < .005 and 0.57, P < .001, for CC and MLO views, respectively). Low-level contrast resolution was equal in both units using standard acquisition parameters.


CONCLUSIONS
In clinical mammographies, higher energy beam spectra obtained using W/Rh anode/filter combinations may significantly contribute to lowering AGD compared to Mo/Mo, Mo/Rh, and Rh/Rh in breasts that are not extremely dense.
Engelken
Florian J F
FJ
Institut für Radiologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany. florian.engelken@charite.de
Meyer
Henning
H
Juran
Ralf
R
Bick
Ulrich
U
Fallenberg
Eva
E
Diekmann
Felix
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D001940:Breast; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008327:Mammography / Q000295:instrumentation*; D008875:Middle Aged; D009928:Organ Specificity; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity