Estimation of the firing distance through micro-CT analysis of gunshot wounds

Abstract

Estimation of the firing range is often critical for reconstructing gunshot fatalities, where the main measurable evidence is the gunshot residue (GSR). In the present study intermediate-range gunshot wounds have been analysed by means of a micro-computed tomography (micro-CT) coupled to an image analysis software in order to quantify the powder particles and to determine the firing distance. A total of 50 shootings were performed on skin sections obtained from human legs surgically amputated for medical reasons. For each tested distance (5, 15, 23, 30 and 40 cm), firing was carried out perpendicularly at the samples using a 7.65-mm pistol loaded with jacketed bullets. Uninjured skin sections were used as controls. By increasing the firing distance, micro-CT analysis demonstrated a clear decreasing trend in the mean GSR percentage, particularly for shots fired from more than 15 cm. For distances under 23 cm, the powder particles were concentrated on the epidermis and dermis around the hole, and inside the cavity; while, at greater distances, they were deposited only on the skin surface. Statistical analysis showed a nonlinear relationship between the amount of GSR deposits and the firing range, well explained by a Gaussian-like function. The proposed method allowed a good discrimination for all the tested distances, proving to be an objective, rapid and inexpensive tool for estimating the firing range in intermediate-range gunshot wounds

Is it possible to determine firearm calibre and shooting range from the examination of gunshot residue in close range gunshot wounds? An experimental study

“…Gunshot analysis has been widely studied in the forensic literature for the estimation of the fi ring range and in the last decades a lot of techniques have been used for the detection and identifi cation of GSR particles in the gunshot wound (11). Th ese experiments have clarifi ed that the amount is strictly correlated to the shooting distance (2,12,13). Th ere are many histochemistry (12-15) studies and electron microscopy methods who are accurate and precise for estimating fi ring distance (16,17).…”

“…from the bullet and cartridge case (2). In the matter of reconstruction of gunshot fatalities, the macroscopic examination of gunshot wounds as well as the investigation of GSR particles gains extensive forensic signifi cance (1,2).…”

“…In the matter of reconstruction of gunshot fatalities, the macroscopic examination of gunshot wounds as well as the investigation of GSR particles gains extensive forensic signifi cance (1,2). Physical and chemical investigations of fi rearm discharge residues are nowadays performed routinely in order to solve a number of forensic problems such as identifi cation of gunshot wounds together with establishing of the entrance and exit (3), estimation of the time since discharge of a fi rearm (4,5), distribution of GSR at the crime scene, estimation of shooting distance (6,7), as well as establishing whether a person has fi red a gun (8).…”

Micro-CT features of intermediate gunshot wounds covered by textiles

“…Beside visual inspection, chemical investigation, immunohistochemistry, and scanning electron microscopy coupled with energy-dispersive X-ray analysis, which are widely used tools for GSR identification, in the last decade, microcomputed tomography (micro-CT) has been applied to the identification and quantification of GSR around and inside the gunshot wound cavity [6][7][8][9].…”

Performance of post-mortem CT compared to autopsy in children

“…Post-mortem imaging (PMI) methods, including conventional radiography, computed tomography (CT) with or without contrast agent injection, and magnetic resonance imaging (MRI), have been applied and evaluated in many cases, including the detailed analysis of traffic accidents [3][4][5], detection of sources of bleeding [6,7], bone age estimation [8,9], gunshot injuries [10][11][12][13], and deaths occurring during or shortly after surgery [14]. PMI may add substantial information to the results of conventional autopsy and, in some cases, may serve as a non-or minimally invasive alternative method to conventional autopsy, especially if conventional autopsy cannot be performed.…”