IEC 60627 pdf download.Diagnostic X-ray imaging equipment – Characteristics of general purpose and mammographic anti-scatter grids
1 Scope and object
This International Standard deals with the definitions, determination and indication of characteristics of ANTI – SCATTER GRIDS used in diagnostic X-ray imaging equipment, in order 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 . 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 for MAMMOGRAPHIC ANTI – SCATTER GRIDS . 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 demonstration of the characteristics of ANTI – SCATTER GRIDS under test conditions. These conditions are not usually available at the USER ‘s site.
3.1 Degree of requirements In this standard, certain terms which are not printed in SMALL CAPITALS have particular meanings: – “shall” indicates a requirement that is mandatory for compliance; – “should” indicates a strong recommendation that is not mandatory for compliance; – “may” indicates a permitted manner of complying with a requirement or of avoiding the need to comply; – “specific” is used to indicate definitive information stated in this standard or referenced in other standards, usually concerning particular operating conditions, test arrangements or values connected with compliance; – “specified” is used to indicate definitive information stated by the MANUFACTURER in ACCOMPANYING DOCUMENTS or in other documentation relating to the EQUIPMENT under consideration, usually concerning its intended purpose, or the parameters or conditions associated with its use or with testing to determine compliance. 3.2 Use of terms In this standard, terms printed in SMALL CAPITALS are used as defined in IEC 60601-1, in IEC 60788, in 3.3 of this standard or in other IEC publications referenced in annex B. NOTE Attention is drawn to the fact, that in cases where the concept addressed is not strongly confined to the definition given in one of the publications listed above a corresponding term is printed in lower-case letters. An index of defined terms used in this standard is given in annex B. 3.3 Defined terms For the purpose of this International Standard, the following definitions apply. NOTE Some of the defined terms given in this standard deviate from those given in the current edition of IEC 60788. 3.3.1 ANTI – SCATTER GRID device with a fixed periodic arrangement of materials with different X-ray ATTENUATION properties to be placed in front of the IMAGE RECEPTION AREA in order to reduce the incidence of SCATTERED RADIATION upon that area and thus increase the contrast in the X- RAY PATTERN 3.3.4 FOCUSED GRID LINEAR GRID in which the planes of the absorbing strips converge to a straight line at the FOCUSING DISTANCE 3.3.5 TAPERED GRID LINEAR GRID in which the height of the absorbing strips decreases as the distance between the absorbing strips and the TRUE CENTRAL LINE increases. This decrease is symmetrical about the TRUE CENTRAL LINE 3.3.6 CROSS – GRID ANTI – SCATTER GRID composed of two LINEAR GRIDS built together in such a way that the directions of their absorbing strips form an angle 184.108.40.206 ORTHOGONAL CROSS – GRID CROSS – GRID in which the directions of the absorbing strips form an angle of 90° 220.127.116.11 OBLIQUE CROSS – GRID CROSS – GRID in which the directions of the absorbing strips form an angle other than 90° 3.3.7 STATIONARY GRID ANTI – SCATTER GRID used in such a way that it does not move in relation to the RADIATION BEAM 3.3.8 MOVING GRID ANTI – SCATTER GRID used in an ACCESSORY that enables the ANTI – SCATTER GRID to be moved, when irradiated by a RADIATION BEAM , in order to avoid the imaging of the absorbing strips and the consequent loss of information 3.3.9 MAMMOGRAPHIC ANTI – SCATTER GRID FOCUSED GRID specially designed for mammography NOTE In this standard the term “general purpose ANTI – SCATTER GRID ” is used to describe any ANTI – SCATTER GRID not specially designed for mammography. 3.3.10 Geometric characteristics 18.104.22.168 GRID RATIO , r ratio between the height of the absorbing strips and the distance between the absorbing strips in the centre of a LINEAR GRID