本文件规定用X射线照相法测定由放射性核素铱192、镱169、硒75或钴60制成的0.5mm或更大的伽玛射线源的尺寸。γ射线源的源尺寸是影响γ射线图像质量的重要因素。源尺寸的测定精度为±10%，但通常不超过±0.1 mm。源尺寸由制造商提供，作为源插件的机械尺寸。如果在将源实施到保持架后，对制造过程进行验证或监控，则可能需要进行测量。本文件经验证后可用于其他放射性核素。标准试验方法ASTM E1114提供了关于Ir-192源尺寸测量、源形状特征及其正确组装和包装的进一步信息。

This document specifies the determination of the size of gamma radiographic sources of 0,5 mm or greater, made from the radionuclides Iridium 192, Ytterbium 169, Selenium 75 or Cobalt 60, by a method of radiography with X-rays. The source size of a gamma radiography source is an important factor which affects the image quality of gamma ray images. The source size is determined with an accuracy of ± 10 % but typically not better than ± 0,1 mm. The source size is provided by the manufacturer as the mechanical dimension of the source insert. A measurement may be required if the manufacturing process is validated or monitored after implementation of the source into the holder. This document can be used for other radionuclides after validation. The standard test method ASTM E1114 provides further information on the measurement of the Ir-192 source size, the characterization of the source shape, and its correct assembly and packaging.