The role of computed tomography in terminal ballistic analysis

Abstract

Terminal ballistics concerns the science of projectile behaviour within a target and includes wound ballistics that considers what happens when a projectile strikes a living being. A number of soft tissue ballistic simulants have been used to assess the damage to tissue caused by projectiles. Standard assessment of these materials, such as ballistic soap or ordnance gelatine, requires the block to be opened or that a mould to be made to visualize the wound track. This is time consuming and may affect the accuracy of the findings especially if the block dries and alters shape during the process. Therefore, accurate numerical analysis of the permanent or temporary cavity is limited. Computed tomography (CT) potentially offers a quicker non-invasive analysis tool for this task. Four commercially purchased ballistic glycerine soap blocks were used. Each had a single firearm discharged into it from a distance of approximately 15 cm using both gunshot and shotgun projectiles. After discharge, each block was imaged by a modern 16 slice multi-detector CT scanner and analysed using 3-D reconstruction software. Using the anterior-posterior and lateral scout views and the multi-plane reconstructed images, it was possible to visualize the temporary cavity, as well as the fragmentation and dispersal pattern of the projectiles, the distance travelled and angle of dispersal within the block of each projectile or fragment. A virtual cast of the temporary cavity can be also be made. Multi-detector CT with 3-D analysis software is shown to create a reliable permanent record of the projectile path allowing rapid analysis of different firearms and projectiles.

Effect of shortening the barrel in contact shots from rifles and shotguns

“…The results once more underline the usefulness of an inderdisciplinary approach to experimental wound ballistics, as was also emphasized recently in some other publications [17][18][19].…”

“…Computed tomography has repeatedly been used in studies of wound ballistics (e.g., [15][16][17]). By applying it to the determination of cavity volumes in simulants, as described in this paper, sectional measurements can be performed, allowing exact conclusions as to the energy released along the bullet path.…”

Secondary skull fractures in head wounds inflicted by captive bolt guns: autopsy findings and experimental simulation

“…Recently, computed tomography has been introduced into ballistic research as a non-invasive tool for visualization and numerical analysis of the permanent and temporary cavity in glycerin soap [12,17,32]. Sectional measurements can be performed without manipulating the soap block and allow exact conclusions as to the energy released along the bullet's and bolt's path, respectively.…”

Suicide by shooting with a tiling hammer

“…This revealed that this device had been used in the present case and that it was possible to create the energy and projectile velocity necessary to penetrate the chest in a manner consistent with the victim's wound channel. More recent publications have suggested a CT-based approach for the ballistic analysis in firearm deaths [18].…”