The establishment and implementation of Indonesian diagnostic reference levels: a national framework for optimizing medical radiation exposure

Diagnostic Reference Levels (DRLs) are a fundamental instrument for optimizing patient radiation protection in medical imaging. However, establishing and sustaining a nationally representative DRL system in a geographically vast and resource-diverse country presents significant methodological, regulatory, and operational challenges. Ensuring nationwide dose reporting, harmonizing heterogeneous examination protocols, and translating benchmark values into sustained clinical optimization remain complex tasks, particularly in large archipelagic settings. This study presents Indonesia's experience in establishing, implementing, and periodically reviewing its national DRLs across all major diagnostic modalities through a regulator-led national dose optimization framework. The Indonesian DRLs was established through a nationwide dose survey using the National Patient Dose Data Information System, enabling cumulative nationwide dose data collection from more than 1000 licensed healthcare facilities between 2015 and 2025. Dose data were obtained using direct and indirect dosimetry methods, and Indonesian DRL (IDRL) values were derived as the 75th percentile of facility median doses following regulator-led multi-stakeholder validation. Indonesian DRLs have been established for general radiography, computed tomography (CT), interventional fluoroscopy, mammography, dental radiography, and diagnostic nuclear medicine. The IDRL is subject to periodic review at least every five years, or earlier in response to significant technological advancements or changes in clinical practice. The 2025 review showed reduced DRL values in radiography and CT, indicating improved optimization practices, whereas increases in interventional fluoroscopy reflected growing procedural complexity and the need for complexity-adjusted approaches. Key challenges include variable facility participation, heterogeneous examination protocols, gaps in dosimetry expertise, and a shortage of medical physicists. Indonesia's experiences highlight that sustainable DRL implementation requires robust data systems, stakeholder engagement, regulatory enforcement, and capacity building. This experience offers valuable insights for other large and diverse countries seeking to establish effective national DRL frameworks.