National and Local Diagnostic Reference Levels for 18F-FDG and CT in Jordanian PET/CT Scanning: Findings and Implications in Practice

Background: Positron emission tomography-computed tomography (PET/CT) is a widely utilized hybrid imaging technique that combines functional and anatomical information. To ensure the safe and effective use of this imaging modality, Diagnostic Reference Levels (DRLs) have been established as standardized benchmarks for assessing and managing radiation doses in clinical practice. Several studies have reported DRLs for different radiotracers and imaging modalities, including PET/CT. However, there is a need for country-specific DRL data that reflect national clinical practices. While existing literature provides insights into DRLs for PET/CT procedures in various settings, there is a lack of PET/CT DRLs specific to the Jordanian context. Given the variations in patient populations, equipment specifications, and clinical protocols, it is crucial to establish NDRLs and local DRLs (LDRLs) in Jordan. Therefore, the study aimed to derive the country-specific reference levels for fluoride-18 fluorodeoxyglucose (18F-FDG) PET/CT scans in Jordan. Results The survey revealed that Jordanian NDRL for administered activity (AA) (303 MBq) was within the acceptable range compared to the published-peer NDRL data (240 to 590 MBq). However, the 18 F-FDG AA varied across the participated PET/CT centres. The reported LDRL CTDI vol and DLP of CT used for attenuation correction and anatomical localization (AC-AL) was 4.3 mGy and 459.3 mGy.cm for half-body (HB) CT scan range, and 4.05 mGy and 659.9 mGy.cm for whole-body (WB) CT scans. The reported LDRL for CTDI vol and DLP for HB CT was higher when compared with the United Kingdom (3.2 mGy and 310 mGy.cm). Meanwhile, it remained higher than both Kuwait (3.6 mGy and 659 mGy.cm) and Slovenia (3.6 mGy and 676 mGy.cm) for WB CT. The reported HB attenuation correction diagnostic CT(AC-DX) CT was higher than previously identified peer-reviewed NDRL data and lower than Slovenia for WB AC-DX CT acquisition protocols. Conclusion This study reported the first Jordanian NDRL for 18 F-FDG and LDRL for HB and WB CT associated with 18 F-FDG PET/CT scans. The data provides a valuable reference point for Jordanian PET/CT centres to compare their LDRL with the suggested DRLs. By utilizing this data, centres need to optimize CT radiation doses and tailor them to ensure appropriate image quality.