Background <p>Whole body computed tomography (WBCT) is widely used in the initial assessment of pediatric trauma patients to rapidly identify injuries; however, its routine use exposes children to substantial ionizing radiation. Clear guidance on which pediatric trauma patients truly benefit from WBCT is lacking, leading to practice variability and potential overuse in emergency departments. The proposed score is intended to complement existing pediatric imaging decision frameworks that emphasize selective and risk-based use of computed tomography.</p> Methods <p>This retrospective, single-center observational study included trauma patients under 18 years of age who underwent WBCT in a tertiary pediatric trauma center between June 2021 and June 2022. The primary outcome was the presence of traumatic injuries involving ≥ 2 anatomical regions on WBCT not necessarily the clinical need for WBCT. Candidate predictors were identified from the literature and clinical practice and evaluated using multivariable logistic regression. Continuous variables were dichotomized based on receiver operating characteristics (ROC) analysis. Independent predictors were used to develop a clinical decision support tool, the WHOLE score. Model performance was assessed using ROC analysis and diagnostic accuracy metrics.</p> Results <p>A total of 407 pediatric trauma patients who underwent WBCT were included; 37.6% (<i>n</i> = 153), had injuries involving two or more anatomical regions. Independent predictors of multi-region injury were age ≥ 133 months, tachycardia, hypoxia, positive physical examination findings in the head, thoracic, pelvic, or lower extremity regions, and aspartate aminotransferase (AST) ≥ 50 U/L. These variables were incorporated into the WHOLE score (range 0–8). The WHOLE score demonstrated good discrimination (AUC 0.84; 95% CI 0.80–0.88). Using a cut-off of ≥ 2 points, sensitivity was 96.7% (CI 92.5–98.9) and NPV was 94.8% for detecting multi-region injuries.</p> Conclusions <p>The WHOLE score is a simple clinical decision support tool designed to identify pediatric trauma patients at low risk for multi-region injuries, thereby supporting emergency physicians in safely withholding WBCT in appropriately selected cases. The score functions as a rule-out tool: a low score (0–1) may support a decision to forego WBCT, whereas a high score does not independently mandate it. By reducing unnecessary WBCT in low-risk patients, the score has the potential to decrease radiation exposure while maintaining diagnostic safety. This is a preliminary single-center derivation study, and external prospective validation is required before routine clinical implementation.</p> Trial registration <p>The study protocol was registered retrospectively at clinicaltrials.gov (Clinical Trials Identifier: NCT07411235, Date:11/02/2026).</p>