The mammography images obtained in thismanner had the desired spatial resolution (20 lp mm 1), but had a less than desirable radiographic contrast. This combination of "high entrance dose" with "low radiographic contrast" was not an acceptable approach. The radiology community was searching for a new breast imaging solution. In the 1970s, xeromammography imaging plates provided the much needed improvement in image quality and lowered the breast entrance dose by a factor of two thirds to one half compared to using the thick emulsion industrial type film (9).
Figure 1. Geometric arrangement of conventional radiography.
The portable x-ray machine system, the anatomy of interest, and the screen-film cassette are centered and aligned for exposure.
Due to its unique patient positioning of breast imaging, the geometrical arrangement of dedicated mammography units should be pointed out. As shown in Fig. 1, with the range of 50–60 kVp. Breast tissues contain no high attenuation anatomy, such as bones, a lower tube potential (
The article comes from:http://www.medicalequipment-msl.com/htm/medical-device-news/The-initially-use-in-X-RAY-MAMMOGRAPHY.html
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