Local diagnostic reference levels for routine chest X-ray examinations: first pilot study in Kazakhstan

X-ray imaging is one of the most frequently used diagnostic tools in Kazakhstan and globally. Despite its clinical benefits, it involves exposure to ionizing radiation, requiring dose optimization. The International Atomic Energy Agency (IAEA) recommends establishing Diagnostic Reference Levels (DRLs) to enhance radiation protection in diagnostic radiology. This study aimed to propose local DRLs for posteroanterior (PA) chest radiography in adult patients in selected medical centers in Astana, Kazakhstan. A secondary objective was to assess the quality control of X-ray systems used in routine clinical practice. The study was performed across three diagnostic centers, each using different radiography systems: Siemens Axiom Aristos MX (2009), Siemens Opti 150/30/50HC-100 (2007), and Floormounted DR Series ANGELL TECHNOLOGY DFM818 (2024). Standard chest radiographs were taken from 60 adult patients (≥18 years, 70 ± 20 kg; 20 per system). Entrance Surface Air Kerma (ESAK) and incident air kerma (Ki) were measured using calibrated RTI X-ray multimeters. Exposure parameters were recorded, and descriptive statistics and comparative analysis (Stata 16) were used to analyze the data. ESAK and Ki values showed significant differences among systems (p < 0.05), with older units yielding higher doses. These findings support the proposal of preliminary local DRLs for adult chest radiography in Astana. This study provides the first local DRLs for Kazakhstan and highlights the need for nationwide DRL implementation, aligned with IAEA safety standards (GSR Part 3, SSG-46), to improve radiation protection and diagnostic quality.