title: Refrigeration and freezing of porcine tissue does not affect the retardation of fragment simulating projectiles.
abstract: Explosively propelled fragments are the most common cause of injury to UK service personnel in modern conflicts. Numerical injury models to simulate such injuries utilise algorithms based upon gelatin and animal tissue testing but data is limited on many fragment simulating projectiles and these simulants cannot represent human anatomy. Testing with post mortem specimens may overcome this limitation but no information exists about how post mortem tissue changes and storage conditions in humans or animals may affect projectile penetration. Two chisel nosed cylinders (0.49 g and 1.10 g) and a 0.51 g (5 mm) sphere were fired into three groups of porcine tissue (fresh, refrigerated and frozen then refrigerated) and compared to 20% gelatin. Depth of projectile penetration was ascertained with the assistance of computed tomography and kinetic energy absorption by tissues measured using Doppler radar and high speed photography. No difference in depth of penetration was found between porcine tissue stored in the different manners compared with 20% gelatin by impact velocities less than 100 m/s. Insufficient numbers of projectiles were retained in tissue at higher velocities for statistical analysis to be undertaken. Energy absorbed per millimetre of tissue ranged between 0.42 and 0.98 J/mm for different porcine tissue despite differing storage. This pilot study would suggest that the effect of refrigerating or freezing porcine tissue followed by thawing has no effect on its ability to retard these projectiles. Further research is required to ascertain if these results occur at greater velocities and for other types of projectile.
authors.affiliation: Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham Research Park, Birmingham B15 2SQ, United Kingdom. Electronic address: johno.breeze@me.com.
authors.forename: J
authors.initials: J
authors.lastname: Breeze
authors.affiliation: Impact and Armour Group, Centre for Defence Engineering, Cranfield Defence and Security, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom.
authors.forename: D J
authors.initials: DJ
authors.lastname: Carr
authors.affiliation: Impact and Armour Group, Centre for Defence Engineering, Cranfield Defence and Security, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Mabbott
authors.affiliation: Cranfield Forensic Institute, Cranfield Defence and Security, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Beckett
authors.affiliation: The Royal British Legion Centre for Blast Injury Studies at Imperial College London, London, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Clasper
mesh_terms: D000818:Animals; D044709:Forensic Ballistics / Q000379:methods*; D005615:Freezing; D008954:Models, Biological; D012034:Refrigeration; D013048:Specimen Handling / Q000379:methods*; D013552:Swine
keywords: Ballistic; Gelatin; Military; Penetration