IEC 60627:2013 is applicable to anti-scatter grids used in medical diagnostic X-ray imaging equipment. Anti-Scatter Grids are used to reduce the incidence of scattered radiation, produced particularly in the body of the patient, upon the image reception area and thus to improve the contrast of the X-ray pattern. This International Standard specifies the definitions, determination and indication of characteristics of anti-scatter grids. In this standard only linear grids are considered. Since at present only focused grids are used in mammography, this standard is restricted to focused grids where mammographic anti-scatter grids are concerned. This standard is not intended to be applied for acceptance tests. This standard does not cover the homogeneity of performance over the area of a grid. This standard is intended to be applied for the determination of the characteristics of anti-scatter grids under test conditions. These conditions are not usually available at the site of the responsible organization. This third edition cancels and replaces the second edition published in 2001, and constitutes a technical revision. In this revision calcium tungstate phosphor fluorescent screens, which are no longer available, have been replaced by gadolinium oxysulphide (GOS) fluorescent screens. Further, a new quality parameter is introduced: the Image Improvement Factor or Q-factor, which better describes the properties of the anti-scatter grid, especially for digital detector applications. Further differences between this third edition and the previous second edition are: - new instrumentation is prescribed for measurements of the transmission of primary radiation, the transmission of scattered radiation and the transmission of total radiation, because fluorescent screens made of calcium tungstate phosphors are outdated and are no longer available; - the definition of the phantom used for measurements of the transmission of primary radiation, the transmission of ...