Setting the benchmark : morocco's first local diagnostic reference levels by clinical indication for pediatric computed tomography across all protocols.

PURPOSE: Optimizing radiation protection in pediatric computed tomography (CT) requires diagnostic reference levels (DRLs) adapted to local practice and clinical indication. This study establishes the first Moroccan pediatric CT DRLs stratified by anatomical protocol and diagnostic purpose.

METHODS

A descriptive-analytical study was conducted at a single center including 224 children (≤ 15 years) who underwent CT examinations across four main protocols: head, thorax, abdomino-pelvic and thoraco-abdomino-pelvic (TAP). Dosimetric indices (CTDIvol, DLP) and effective doses (E) were analyzed per ICRP recommendations, and DRLs were derived from the 75th percentile of patient-level dose data by clinical indication.

RESULTS

Head CT was the most frequent (54%), dominated by trauma (63.6%) with optimized exposure (median CTDIvol 21.5 mGy; E 3.1 mSv). Structural pathologies showed lower doses (E 2.2 mSv), while infectious cases reached the highest (E 7.2 mSv) due to extended protocols. Thoracic CT exhibited variability, with cardiovascular/malformative cases showing the highest exposures (E 5.8 mSv) and functional respiratory cases the lowest (E 4.0 mSv). Abdomino-pelvic CT delivered the highest doses in tumoral imaging (E 23.6 mSv) and TAP protocols showed comparable DRLs for tumoral and traumatic cases (~ 15-16 mSv).

CONCLUSION

Clinical indication significantly influences pediatric CT dose, with up to five-fold variation across subgroups. The DRLs established here provide the first national benchmarks for Morocco, supporting protocol optimization, radioprotection policy development and ALARA-compliant pediatric imaging practice.