Küchler M, Friedrich M
Abteilung für Radiologie und Nuklearmedizin, Krankenhaus Am Urban, Berlin.
Aktuelle Radiol. 1992 Jul;2(4):205-11.
The visibility of microcalcifications in mammography is limited, inter alia, by the dimensions of the focal spot of the x-ray tube. The user should be able to evaluate a given nominal value of the focal spot and to assess the effective size of the focal spot in his x-ray tube. Determination of the resolution with the help of the mammographic phantom suggested by the German DIN standards specifications requires special care. In the framework of the German Mammography Study, 45 mammography devices at different locations were tested with regard to their focal spot sizes. All devices complied with the acceptance test without any adverse comment, although--if judged objectively--only half of them have the resolution demanded by DIN standards. Consequently, in most of the cases the users are unaware of this, and the negative effects on the visibility of possibly present microcalcifications are often underestimated. The diagnostic importance of microcalcifications for the detection of breast cancer suggests, however, to abstain from devices which are only of limited usefulness in relevant mammography screening.
乳腺钼靶摄影中微钙化的可见性尤其受到X射线管焦点尺寸的限制。用户应该能够评估焦点的给定标称值，并评估其X射线管中焦点的有效尺寸。借助德国DIN标准规范建议的乳腺摄影体模来确定分辨率需要格外小心。在德国乳腺摄影研究的框架内，对不同地点的45台乳腺摄影设备的焦点尺寸进行了测试。所有设备都通过了验收测试，没有任何负面评价，尽管——如果客观判断——其中只有一半设备具有DIN标准要求的分辨率。因此，在大多数情况下，用户并不知道这一点，而且对可能存在的微钙化可见性的负面影响常常被低估。然而，微钙化对乳腺癌检测的诊断重要性表明，应避免使用在相关乳腺钼靶筛查中实用性有限的设备。
