The authors of these studies concluded that visual assessments and caliber measurements on CT are often impeded or infeasible since lodged bullets are frequently heavily deformed or fragmented. The feasibility of visual assessment or caliber measurement of lodged bullets using CT was assessed on real shooting victims in postmortem studies. The in situ identification of a bullet can be particularly interesting in forensic investigations when a lodged bullet will not be removed from the patient, for example, to avoid the risk of neural damage due to an intervention. Ballistic experts examine bullets secured at a crime scene or removed from a body, and laboratory analysis of the deposits from an entrance wound can provide information on the bullet used. This study presents a viable method for distinguishing copper and lead bullets in situ via CT and highlights the potential pitfalls of incorrect classifications.Ĭomputed tomography (CT) allows identification of the location of a lodged projectile and detection of gunshot residues indicating a contact shot. The 120/140 DEIs calculated from the maximum CT numbers obtained from ROIs at the edge of copper versus lead bullets presented a significant difference ( p = 0.002) and a gap between the CT numbers of copper and lead bullets and was successfully applied for the decedents. DEI calculations revealed significant differences between the two groups of bullets. ResultsĬT numbers demonstrated no significant difference between copper and lead bullets, and false classifications can easily occur. The most appropriate method was applied for decedents with fatal gunshot wounds. In addition to comparing CT numbers, the dual-energy index (DEI), representing the ratio between the CT numbers of two energy levels, was calculated. CT numbers were measured within regions of interest (ROIs). Copper and lead bullets were fired into animal cadavers, which then underwent CT scanning at four energy levels (80, 100, 120, and 140 kVp). MethodsĮthical approval was not required (animal cadavers) or waived by the ethics committee (decedents). Independent from the bullet’s intactness, x-ray attenuation values (CT numbers) may provide information regarding the material of the bullet. Although computed tomography (CT) is usually performed on shooting victims, visual assessment, or caliber measurements using CT can be challenging or infeasible if the bullets are deformed or fragmented. The in situ classification of bullets is of interest in forensic investigations when the bullet cannot be removed.
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