Journal article
The influence of 1.5 and 3 T magnetic resonance unit magnetic fields on the movement of steel-jacketed projectiles in ordnance gelatin.
- Eggert S Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, Zurich, 8057, Switzerland.
- Kubik-Huch RA Department of Radiology, Kantonsspital Baden AG, Baden, Switzerland.
- Lory M Forensic Institute Zurich, Zurich, Switzerland.
- Froehlich JM Federal Institute of Technology, Pharmaceutical Sciences, Zurich, Switzerland.
- Gascho D Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, Zurich, 8057, Switzerland.
- Thali MJ Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, Zurich, 8057, Switzerland.
- Bolliger SA Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, Zurich, 8057, Switzerland. stephan.bolliger@irm.uzh.ch.
- 2015-10-31
Published in:
- Forensic science, medicine, and pathology. - 2015
Bullets
Ferromagnetic foreign bodies
MR
MR safety
Firearms
Forensic Ballistics
Gelatin
Humans
Magnetic Fields
Magnetic Resonance Imaging
Models, Biological
Multidetector Computed Tomography
English
PURPOSE
Ferromagnetic bullets can move in air or gelatin in magnetic resonance (MR) units. According to our experience, ferromagnetic bullets do not always present consistent movement. We examined factors affecting ferromagnetic projectile movement in a 1.5T and a 3T MR unit, focusing in this study on the steel-jacketed Swiss ordnance ammunition 7.5 mm GP11 Suisse.
METHODS
Five 7.5 mm GP11 Suisse bullets were embedded horizontally and vertically in 10 % ordnance gelatin phantoms. Before and after exposing the bullets to 1.5T (Siemens) and 3T (Philips) MR units each bullet's position was documented by a CT scan. In a second phase, the magnetic polarization of the bullets in relation to the MR units was measured by a dry magnetic portable compass (Suunto).
RESULTS
Our results showed that the displacement of the bullets increased when subjected to a stronger magnetic field (max. Movement 1.5T: 24.4 mm vs. 3T: 101.5 mm) and that the position, i.e. orientation of the bullet toward the gantry, strongly influenced its mobility (horizontally embedded projectiles showed poor movement, vertically placed ones strong movement). One of the bullets presented a 180° rotation in the 3T MR unit. Magnetization and changing of the polarization of these ferromagnetic bullets is possible when subjected to MR units.
CONCLUSION
In conclusion, the location of a bullet, and its orientation toward the gantry must be taken into account when assessing the risk of performing an MR examination on a gunshot victim in clinical and in forensic cases.
Ferromagnetic bullets can move in air or gelatin in magnetic resonance (MR) units. According to our experience, ferromagnetic bullets do not always present consistent movement. We examined factors affecting ferromagnetic projectile movement in a 1.5T and a 3T MR unit, focusing in this study on the steel-jacketed Swiss ordnance ammunition 7.5 mm GP11 Suisse.
METHODS
Five 7.5 mm GP11 Suisse bullets were embedded horizontally and vertically in 10 % ordnance gelatin phantoms. Before and after exposing the bullets to 1.5T (Siemens) and 3T (Philips) MR units each bullet's position was documented by a CT scan. In a second phase, the magnetic polarization of the bullets in relation to the MR units was measured by a dry magnetic portable compass (Suunto).
RESULTS
Our results showed that the displacement of the bullets increased when subjected to a stronger magnetic field (max. Movement 1.5T: 24.4 mm vs. 3T: 101.5 mm) and that the position, i.e. orientation of the bullet toward the gantry, strongly influenced its mobility (horizontally embedded projectiles showed poor movement, vertically placed ones strong movement). One of the bullets presented a 180° rotation in the 3T MR unit. Magnetization and changing of the polarization of these ferromagnetic bullets is possible when subjected to MR units.
CONCLUSION
In conclusion, the location of a bullet, and its orientation toward the gantry must be taken into account when assessing the risk of performing an MR examination on a gunshot victim in clinical and in forensic cases.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.1007/s12024-015-9725-1
- PMID 26514689
- Persistent URL
- https://sonar.ch/global/documents/35996
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