T. Amalia et al. / Atom Indonesia Vol. 48 No. 2 (2022) 159 - 167 The Establishment of Institutional Diagnostic Reference Levels (DRLs) in the Cipto Mangunkusumo Hospital T. Amalia 1 *, B. Zulkarnaien 2 , C. Anam 3 , K. Nurcahyo 1 , H. Tussyadiah 4 , D. E. Pradana 5 1 Installation of Radiology and Nuclear Medicine, dr. Cipto Mangunkusumo Hospital, Jakarta 10430, Indonesia 2 Medical Staff Group of Radiology and Nuclear Medicine, dr. Cipto Mangunkusumo Hospital, Jakarta 10430, Indonesia 3 Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Semarang 50275, Indonesia 4 Integrated Heart Service Installation, dr. Cipto Mangunkusumo Hospital, Jakarta 10430, Indonesia 5 RSCM-Kiara, dr. Cipto Mangunkusumo Hospital, Jakarta 10430, Indonesia A R T I C L E I N F O A B S T R A C T Article history: Received 17 March 2021 Received in revised form 14 December 2021 Accepted 15 December 2021 Keywords: Diagnostic reference levels Diagnostic radiology Optimization Patient safety Institutional diagnostic reference levels are used for quality assurance in radiology departments. The purpose of this study was to establish an institutional diagnostic reference level (DRL) and to provide a practical tool in diagnostic radiology and nuclear medicine. For each type of procedure/examination, it needs at least 20 patients. The patients with regular size (average body size is 65 ± 10 kg for adult patients and 15±15 kg for pediatric patients) were enrolled in this project. The 75 percentile values of doses were used as institutional DRLs. For nuclear medicine, the administered activities was based on the dose of activity to produce a good image. The DRL values were obtained for general radiography, nuclear medicine, mammography, CT examination, and interventional radiography. The DRL's result was compared to national DRL (NDRL) and values in other countries. The DRL values for general radiography in this study are higher compared to NDRL and Japanese study. The administered activities (MBq) for nuclear medicine in this study are higher compared to European Commission but lower when compared to a Japanese study. The DRL values for mammography in this study are higher compared to ARPANSA; however, they are lower than NDRL and UK studies. The DRL values for CT examination in this study are higher compared to Netherland, Canadian, and USA studies but lower than NDRL. The DRL values in interventional radiography (IR) in this study are lower compared to the IAEA study. This finding indicates that it is still necessary to optimize procedures in the future. The established institutional DRL values can be used as a tool for optimization. © 2022 Atom Indonesia. All rights reserved INTRODUCTION  Optimization is a pillar in the system of radiological protection and safety as defined by the International Commission on Radiological Protection (ICRP) %1]. However, the principle of optimization is complex, and to further clarify the issue, optimization is described as a process depending on various factors [2]. The ICRP describes the optimization for medical exposures as follows: ‘Optimization is best described as the management of radiation dose to the patient to be commensurate with the medical purpose’ [3].  Corresponding author. E-mail address: tuti.amalia08@gmail.com DOI: https://doi.org/10.17146/aij.2022.1131 The radiation dose varies significantly among different diagnostic radiology applications and patients [4]. One core activity in optimization is the management of radiation dose to the patient [5]. One practical tool to manage the radiation dose for diagnostic X-ray examination and nuclear medicine examination is diagnostic reference levels (DRLs) [5]. A DRL is an investigation level used as a tool to aid in the optimization of protection in the medical exposure of patients for diagnostic and interventional procedures. It is used in medical imaging with ionizing radiation to indicate whether, in routine conditions, the amount of radiation used for a specified procedure is unusually high or low for that procedure. For nuclear medicine, the Atom Indonesia Vol. 41 No. xxx (2015) xx xxx Atom Indonesia Journal homepage: http://aij.batan.go.id Atom Indonesia Vol. 48 No. 2 (2022) 159 - 167 159