1 Scope
This document is applicable to X-ray source assemblies and X-ray tube assemblies.
NOTE 1 If, for certain medical electrical systems, special radiation fields are required such that the scope of IEC 60806 does not apply (e. g., using CT collimators with bow-tie filters), the appropriate system particular standard applies.
This document specifies a method for the determination of the greatest geometrically
symmetrical radiation field at a specified distance from the focal spot for which the percentage air kerma rate along the major axes of the radiation field does not fall below a permitted value.
NOTE 2 In practical use air kerma or air kerma rate are the most practical physical measures to quantify X-ray patterns.
In case multiple focal spots are not super-imposed, each focal spot has its own reference axis. Then the maximum radiation field can be given for each focal spot separately.
NOTE 3 The maximum symmetrical radiation field can change from its initial value as the X-ray tube ages through use.