Kp. Hermann et al., DIMA-MAGNIFICATION MAMMOGRAPHY - USE OF PHANTOMS FOR THE INVESTIGATION OF IMAGE QUALITY AND RADIATION EXPOSURE, RoFo. Fortschritte auf dem Gebiete der Rontgenstrahlen und der neuenbildgebenden Verfahren, 167(3), 1997, pp. 304-310
Purpose: A mammographic system has been developed to provide direct ra
diographic magnification; investigation of image quality and radiation
exposure for surveys and aimed exposures were carried out on phantoms
and the results compared with two modern screen methods. Material and
method: Image quality was defined by contrast transfer function, reso
lution of low contrast, contrast of large areas and recognition of low
contrast detail, using suitable phantoms. Measurements of entrance su
rface dose were made with a 1 cm(3) flat chamber. Results: For survey
examinations, the new mammographic system provided image quality equal
to a screen system but using 50% radiation dose. For localised views,
the new system used similar radiation dose but provided significantly
better demonstration of diagnostic detail. Conclusion: Using a focal
spot of 40-120 mu m, the new mammographic system provides markedly imp
roved direct radiographic magnification. With reduced radiation exposu
re at times, there is a significant gain in diagnostic information com
pared with current standard systems.