In search of optimum chest radiography techniques.

A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.

Assessment and comparison of chest radiography techniques in the United States and Sweden.

The United States Center for Devices and Radiological Health and the Swedish National Institute of Radiation Protection started a collaborative project in 1983. The purpose of the project was to test the adequacy and practicability of the United States (US) Nationwide Evaluation of X-ray Trends (NEXT) programme in Sweden. The NEXT protocol for the postero-anterior chest projection was modified and expanded to make it both "statistical" and "investigational" (in the US, NEXT gives mainly "statistical" information). All chest X-ray units in Sweden were surveyed in 1986-87. The project showed that the NEXT programme is applicable to countries other than the United States and provides a standardized protocol that enables intercomparison of the radiological techniques. This paper presents the comparison of the radiological techniques used in Sweden and the United States. The results of the investigational modifications made to the protocol used in Sweden are discussed. Recommendations concerning expansion of the NEXT protocol to include these valuable tools for investigational surveys are presented.