International survey on diagnostic reference levels based on clinical indications in plain radiography

To collect and analyze radiation dose-related data as part of international cooperation; to define diagnostic reference levels (DRL) for 24 X-ray projections in plain radiography (DX) considering anatomical region, clinical task, and procedural technique; and to harmonize the exposure practice across country borders.

A multicenter study was performed in Austria, Germany, Italy, and Switzerland in 2022–23 to provide dose-related data. Healthcare facilities were asked to provide processed data from their dose management systems. A 5%-level was used for assessing the statistical significance of dose differences between various groups.

Dose-related data from 85 radiographic systems in academic and non-academic, public, and private healthcare facilities were analyzed. Dose-related parameters differed significantly for many projections with different clinical tasks and techniques. Dose-related data of the procedures varied by a maximum factor of 16 for the same system, and median dose values also differed between hospitals by a maximum factor of 31. A fifth of the surveyed systems exhibit doses above more than half of the new DRLs defined in this study. Apart from the three reference procedures, no significant dose differences were observed between X-ray systems of different ages, from different manufacturers, or from different countries.

This is the first survey in which exposure practices were investigated in institutions in different central European countries by establishing clinical DRLs for radiography. The observed dose variations could be explained by different reasons, such as non-optimized dose protocols. The new DRLs help to harmonize the exposure practice across country borders.

Question What is the exposure practice for plain radiography procedures for which no clinical diagnostic reference levels (DRLs) have been defined? Are there differences between countries?

Findings The dose for the same clinical task and technique can vary considerably among institutions but, on average, do not significantly differ between neighboring countries in Europe.

Clinical relevance In this international multicenter study, clinical DRLs were defined for 24 plain radiography projections to promote the optimization of the exposure practice, to reduce dose variations among institutions even across national borders, and to strengthen international cooperation among users.