Conclusion

This systematic review and meta-analysis provide the first quantitative synthesis of the application of micro-computed tomography for the detection and characterization of gunshot residue in forensic contexts. Across experimental models, micro-CT consistently identified radiodense inorganic residues and demonstrated a progressive decline in detectable deposition with increasing shooting distance, supporting the biological and physical plausibility of its use as a spatial mapping and screening tool. However, the available evidence base remains limited in size, methodologically homogeneous, and characterized by substantial between-study heterogeneity, with shooting distance explaining only a small proportion of the observed variability. These findings restrict the precision and generalizability of pooled estimates and preclude reliable distance prediction based solely on micro-CT–derived metrics.

Consequently, micro-CT should currently be interpreted as a complementary, non-destructive imaging modality that facilitates three-dimensional localization of potential residues and guides targeted confirmatory analyses rather than serving as a standalone method for elemental identification or definitive shooting-distance estimation. Future research should prioritize independent replication under diverse ballistic conditions, standardized acquisition and segmentation protocols, and integration with compositional techniques, particularly SEM/EDS as the primary confirmatory framework, to establish robust performance benchmarks and define the operational limits of micro-CT within forensic ballistic investigations.