PHANTOM DEVELOPMENT FOR CONSTANCY AND ACCEPTANCE TEST FOR DIGITAL RADIOGRAPHIC EQUIPMENT

摘要

The development of specific phantoms to study the image obtained by computerized and direct digital ra-diographic equipment is the objective of this work to characterize the physical properties of the image chain. We have developed a specific phantom, named RACON, that is applied to an acceptance and constancy test to assess the image quality of digital radiographic equipment. This phantom has been designed with different test objects recommended by international and national associations (IEC-61223-2-9, RD 1976-1999) as low-contrast objects varying in diameter and size for threshold contrast resolution, a high-resolution test for the limitingrnspatial resolution, a dynamic step wedge for the dynamic range of the system, and a homogeneity zone and alignment marks for the position and size of the radiation field. Furthermore, we have developed specific software to analyze automatically and objectively the phantom images. The algorithms are based on digital image processing techniques, and they have been specifically designed for each test object in the phantom. The developed phantom is sensitive enough to the operating conditions of the radiographic digital system, and the automatic image evaluation allows the objective study of the global state of the image system.