IEC 60627 pdf download Diagnostic X-ray imaging equipment — Characteristics of general purpose and mammographic anti-scatter grids
The arrangement shall be as described in 5.2.2 except that the PRIMARY RADIATION blockerand the ANTI-SCATTER GRID are removed.The MEASURED vALUEs of the detector signal shall beobtained with the detector shielded against the light excited in the FLuORESCENT sCREEN, andwith the detector unshielded.
The ratio of these values shall not exceed 0,002.
NOTE A constant dark current of the RADIATION DETECTOR may be subtracted from the MEASURED VALUES.5.1.3 PHANTOMs
a) For general purpose ANTIl-SCATTER GRIDs,the PHANTOM used for the determination of
TRANSMISsION OF PRIMARY RADIATION and for the determination of TRANSMISSION oFSCATTERED RADIATION shall be the PHANTOM described in 8.3 of lEC 61267.This PHANTOMshall be a water-filled container.The container shall have
– sides of outside dimensions of 300 mm ± 1 mm and height of 200 mm ± 1 mm;
– top,bottom and walls made of polymethyl-methacrylate(PMMA) or of other materialhaving similar ATTENUATION properties, each being 10 mm ± 2 mm thick; and
– the interior filled with water.
NOTE When used under NARROW-BEAM CONDITIONs,the above PHANToM may be replaced by a PHANTOMidentical except for reduced outside dimensions.This equivalence should be checked.
NOTE Alternatively to the above PHANTOM，a PHANTOM made up of water-equivalent material (“solid water”)having the same overall dimensions as the container,may be used.This equivalence should be checked.
b) For MAMMOGRAPHIC ANTI-SCATTER GRIDs the PHANTOM used for the determination of
TRANSMISsION OF PRIMARY RADIATION and for the determination of TRANSMISSION OFSCATTERED RADIATION shall be a PMMA block of square cross-section with sides of 150 mmand an area density of 5,95 g · cm-2 ± 0,10 g . cm-2.This corresponds to a thickness ofapproximately 50 mm, as indicated in figure 3b.
a) For general purpose ANTIl-SCATTER GRIDs,the arrangements for the measurements are
shown in figure 3a (PHANTOM in the upper position，NARROW-BEAM CONDITION) and figure 4a(PHANTOM in the lower position，BROAD-BEAM CONDITION).
The positions of the FOcAL SPOT, general purpose ANTI-SCATTER GRID and measuring fieldare the same for both configurations.They are defined in terms of the arrangements withthe PHANTOM in the lower position.
The arrangements for the measurements are similar to the ones described in lEC 61267for the generation of RADIATION QUALITIES RQN and RQB with the following deviations:
– the same PHANTOM may be used in both arrangements;
– the positions of the DIAPHRAGMs are slightly modified;
– the value of the RADIATION BEAM diameter in NARROW-BEAM CONDITIONs shall be 8 mm;- aRADIATION blocker is added for some of the BROAD-BEAM measurements.
The distance from the FOCAL SPoT to the supporting plane of the general purpose ANTl-SCATTER GRID shall be 100 cm ± 1 cm, even if the FocusING DISTANCE of the FocuSED GRIDunder consideration is not 100 cm. For the geometry described, the results of themeasurements are insensitive to the FocuSING DISTANCE fo-