Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Switzerland.
Department of Psychiatry, Psychotherapy and Psychosomatics, Hospital of Psychiatry, University of Zurich, Switzerland.
Med Sci Law. 2020 Jul;60(3):188-195. doi: 10.1177/0025802420911555. Epub 2020 Mar 31.
Special deformation bullets were developed for police forces to achieve a defined penetration depth (avoiding over-penetration) and a controlled energy transfer (avoiding collateral damage). This article focuses on Action 4, SECA and QD-PEP bullets. These 9 mm bullets were specially designed for controlled deformation. The characteristic slight mushrooming with a front cross-section of approximately 11.5 mm after entering a ballistic simulant was verified in ballistic tests. To achieve such slight mushrooming, the projectile's core is hollowed. The purpose of this study was to investigate the feasibility of visualising the hollowed cores of Action 4, SECA and QD-PEP bullets using a standard clinical computed tomography (CT) scanner for non-invasive identification of these special bullets from police ammunitions.
First, undeformed specimens were scanned to reveal the shape of the hollowed core of each type of special bullet. Second, Action 4, SECA and QD-PEP bullets were fired towards animal cadaver models to visualise their hollow core after deformation inside biological tissue. Third, two reviewers were tasked with identifying special bullets from police ammunition (Action 4 bullets: = 3) among 10 CT examinations of humans with lodged projectiles who were selected by the supervisor of the study.
The CT scans of the undeformed specimens revealed the special design of the bullets' metal core. All special bullets from police ammunitions that were fired towards an animal cadaver model demonstrated the characteristic slight mushrooming. In accordance with the CT scans of the undeformed bullets, visualisation of the individual internal cavities of the special bullets allowed the Action 4, SECA and QD-PEP bullets to be clearly distinguished. With regard to the real forensic cases, both reviewers clearly identified each of the three Action 4 bullets among all other lodged projectiles.
This study demonstrates the feasibility of identifying Action 4, SECA and QD-PEP bullets from special police ammunitions by CT. The individual shapes of the cavity inside the bullets were clearly visible on CT. In situ identification of these bullets can aid in the assessment of injuries, and since these bullets are fabricated from non-ferromagnetic metals, their clear identification allows for magnetic resonance imaging (MRI) without the risk of bullet movement inside the body due to the magnetic pull of the MRI unit. Furthermore, this approach could be of great interest to forensic investigators if patients who received gunshot wounds underwent non-operative treatments and the projectile remains in the body. Since the use of CT is also increasing for medico-legal post-mortem examinations, the identification of lodged projectiles is of interest for a virtual autopsy or 'Virtopsy'.
特殊变形子弹是为警察部队开发的，目的是实现特定的穿透深度（避免穿透过度）和可控的能量传递（避免附带损伤）。本文重点介绍 Action 4、SECA 和 QD-PEP 子弹。这些 9 毫米子弹是专门为可控变形设计的。在弹道模拟物中进入后前端横截面约为 11.5 毫米的轻微蘑菇状变形特征在弹道测试中得到了验证。为了实现如此轻微的蘑菇状变形，弹丸的核心被掏空。这项研究的目的是探讨使用标准临床计算机断层扫描（CT）扫描仪对 Action 4、SECA 和 QD-PEP 子弹的空心核心进行可视化的可行性，以便从警察弹药中对这些特殊子弹进行非侵入式识别。
首先，对未变形的样本进行扫描，以揭示每种特殊子弹空心核心的形状。其次，将 Action 4、SECA 和 QD-PEP 子弹发射到动物尸体模型中，以观察它们在生物组织内变形后的空心核心。第三，由研究主管选择的 10 例人体中植入弹丸的 CT 检查中，两位审查员负责识别来自警察弹药的特殊子弹（Action 4 子弹：n=3）。
未变形样本的 CT 扫描显示了子弹金属核心的特殊设计。所有发射到动物尸体模型的警察弹药中的特殊子弹都表现出特征性的轻微蘑菇状变形。根据未变形子弹的 CT 扫描，特殊子弹的各个内部空腔的可视化可以清楚地区分 Action 4、SECA 和 QD-PEP 子弹。在真实的法医案例中，两位审查员都能在所有其他植入弹丸中清楚地识别出三个 Action 4 子弹中的每一个。
本研究证明了通过 CT 识别来自特殊警察弹药的 Action 4、SECA 和 QD-PEP 子弹的可行性。子弹内部空腔的个体形状在 CT 上清晰可见。在体内对这些子弹进行原位识别有助于评估损伤，并且由于这些子弹由非铁磁金属制成，因此它们的清晰识别允许进行磁共振成像（MRI），而不会因 MRI 单元的磁力吸引而导致子弹在体内移动的风险。此外，如果接受枪伤治疗的患者接受非手术治疗且弹丸留在体内，这种方法对法医调查人员也非常有兴趣。由于 CT 也越来越多地用于法医死后检查，因此对于虚拟尸检或“虚拟尸检”来说，识别植入弹丸是有意义的。
