Diagnostic Reference Range (DRR) in Computed Tomography (CT) Imaging Based on Clinical Indications Related to Thorax, Abdomen and Pelvic Regions

The concept of diagnostic reference range (DRR) is introduced to address the balance between a patient’s risk (radiation dose) and benefit (image quality necessary for an accurate diagnosis). R provides minimum estimated dose that covers 25–75% distribution. International Commission on Radiological Protection, ICRP (2017) recommended 75th percentile as upper d 25th lower limit DRR [1]. Dose below should compromise interpretation image above may be in excess need reviewed. Meanwhile, Diagnostic Reference Levels (DRLs) are set at distribution by guidance identify any unusual computed tomography (CT) procedures consistently exceed established DRLs.
 aim this study was establish local CT scanning based clinical indications associated thorax, abdomen, pelvic regions adult patients Department Radiology, Hospital Universiti Sains Malaysia (HUSM), Kelantan. This involved retrospective survey data underwent 5 most common related two departments, Radiology Trauma Department, HUSM. obtained human ethical approval from university committee (Protocol code: USM/JEPeM/22010025). metrics (dose length product, DLP total DLP) technical factors were collected.
 Results showed five cancer staging, coronary artery disease, pulmonary embolism, stones (CTU protocol) (KUB protocol). values varied their scanner types. Figure 1 shows boxplots representing DRRs scans Toshiba Siemens scanners. highest 4722 mGy.cm observed staging using scanner. While lowest value 40 KUB protocol also main factor contributes higher longer length.
 demonstrates descriptor values, similar anatomical region different requirement each indication. Thus, utilisation both DRL crucial minimise unnecessary patient ensure optimum produced scanning.