National Diagnostic Reference Levels in General Radiography: A Scoping Review

The aim of this scoping review was to explore the state of proposed and established national diagnostic reference levels (NDRLs) in general radiography. It examined survey harmonization, radiological examinations, doses, and 20-year international trends in NDRLs. It also highlights NDRL survey strategies for dose optimization. A scoping review of the literature was carried out in accordance with the guidelines of the Preferred Reporting Items for Systematic and Meta-Analyses extension for Scoping Reviews. Searches were conducted in gray literature and electronic databases such as ScienceDirect, PubMed, CINAHL via EBSCOhost, and MEDLINE for NDRLs in general radiography for papers published from January 01, 1990, to April 20, 2024. A total of 4932 studies were identified with 22 articles selected for review. These articles were those based on an adult-human dosimetry survey. The NDRLs were set at the 75th percentile of 7 radiographic examinations and 13 projections. These have been presented with thematic analysis, narrative synthesis, and descriptive statistics. A consistent adherence to guidelines for NDRL surveys was observed despite methodological variations. NDRLs were less prevalent in low- and lower-middle-income countries. Chest PA and lumbar spine examinations were commonly reported, with lumbar spine LAT yielding the highest and chest PA the lowest doses. Proposed NDRLs from 2004 to 2013 indicated higher doses than those from 2014 to 2024, aligning with established NDRLs in the last decade. The introduction of quality control tests and radiographic image quality assessments is recommended to enhance result reliability and support dose optimization strategies, addressing gaps in current practices.