Establishing local diagnostic reference levels (DRLs) for abdomino-pelvic computed tomography (CT) examinations using size-specific dose estimates (SSDE) in Malta

Abstract

Purpose To establish local diagnostic reference levels (DRLs) for abdomino-pelvic computed tomography examinations using size-specific dose estimates (SSDEs) across different patient size categories in Malta, addressing the current gap in national SSDE-based DRLs. Methodology Quantitative, non-experimental, retrospective analysis was carried out on a total of 198 adult patients who underwent abdominopelvic CT examinations at Malta’s general hospital. These patients were categorized by BMI class and SSDEs were calculated using the CTDIvol and effective diameter. The 75th percentile values for CTDIvol, DLP, and SSDE were used to establish DRLs. Results The study’s local DRLs abdominopelvic CT examinations based on DLP and CTDIvol are 595.87mGy.cm and 10.67mGy respectively. The proposed SSDE-based DRL is 12.60mGy. These DRL values were generally lower or comparable to international research findings, highlighting effective local dose optimisation. Categorisation by BMI class showed that patients in the obese category consistently received higher DLP radiation doses (950.05mGy.cm) compared to those in the overweight (444.56mGy.cm), and normal weight category (317.90mGy.cm), underscoring the need for further protocol adjustments. Conclusion This research is the first to propose DRLs based on SSDE for abdomino-pelvic CT exams in Malta. The findings suggest that while current CT protocols are optimised, further adjustments based on patient size, particularly in obese patients is important. These results support the integration of SSDE in routine clinical practice to strengthen radiation protection and provide a foundation for the development of national DRLs based on size.