Research review _20240920_095203_0000.pdf

bullet behavior in gelatin block, examine with the help of CT scan

1. THREE-DIMENSIONAL VISUALIZATION
OF GUNSHOT CAVITIES IN BALLISTIC
GELATINE WITH
COMPUTED TOMOGRAPHY
CREDITS:
PETTERI OURA
MIKEAL BRIX
TIMO LIMATAINEN
JUHO ANTTI JUNNO

2. The research explores CT-based 3D reconstruction to digitally visualize gunshot
cavities in ballistic gelatine. Three types of .30 caliber bullets (full metal jacket,
soft point, and expanding monolithic) were fired into gelatine blocks, which were
then scanned using clinical CT equipment. The differences in cavitation between
bullet types were clearly visible, with gelatine segmentation offering higher
resolution. A key benefit of the 3D reconstructions is the ability to freely rotate and
take measurements from any angle, with the data being stored for future analysis.
OVERVIEW

3. INTRODUCTION
This research discusses the importance of 3D imaging, particularly
computed tomography (CT), in the forensic analysis of gunshot injuries. CT
is widely used to reveal critical information such as projectile trajectory and
fragmentation in gunshot victims. In forensic ballistics, materials like
ballistic soap and gelatine are often used to simulate human tissue.CT-
based 3D analysis offers a non-destructive alternative, providing rapid,
accurate, and permanent digital records of gunshot cavities. While previous
research has mainly focused on ballistic soap, this case study aims to
explore the use of CT and 3D reconstruction for visualizing gunshot cavities
in ballistic gelatine, which more closely mimics human tissue. The
experiment involved three types of bullets (full metal jacket, soft point, and
expanding monolithic), and the study introduces a method for digital
analysis that could improve forensic documentation and analysis in both
research and routine forensic practice, with potential applications in
medico-legal and judicial settings.

4. GELATINE BLOCK
TEST FIRING
COMPUTED TOMOGRAPHY
3D RECONSTRUCTION
MATERIAL AND METHODS

5. Three blocks of 10% ballistic gelatine (Gelita, Eberbach, Germany) were prepared
according to Jussila's guidelines.
GELATINE BLOCK
The study used three types of .30 caliber bullets from Norma Precision (Sweden), chosen
for their popularity in hunting, target shooting, and military use
TEST FIRING
The gelatine blocks were CT scanned within 16 hours of firing at Oulu University Hospital,
Finland, using dual-source clinical equipment (Somatom Definition Flash, Siemens).
COMPUTED TOMOGRAPHY
The CT scans were processed using the open-source 3D Slicer platform (version 5.4.0).
The scans were uploaded in DICOM format and visually inspected in axial, sagittal, and
coronal planes.
3D RECONSTRUCTION
MATERIAL AND METHODS

6. RESULT
The Jaktmatch bullet fragmented and rotated at a depth of
25 cm, causing large cavitation (15–20 cm wide) near the
top-right corner of the gelatine block. The Ecostrike and
Oryx bullets traveled more steadily, with the Ecostrike
forming a cavity up to 12 cm deep with a maximum
diameter of 10 cm, and the Oryx creating a larger cavity up
to 25 cm deep with a 10 cm diameter, narrowing to 5 cm.
Gelatine segmentation highlighted smaller cavities more
clearly than air segmentation. The 3D reconstructions
allowed for flexible viewing, rotation, and measurements,
providing detailed visual comparisons of the cavities.
FIG. PHOTOGRAPH OF THE ECOSTRIKE GELATINE BLOCK
(A), THE CORRESPONDING COMPUTED TOMOGRAPHY RECONSTRUCTION
(B), AND A FUSION IMAGE COMBINING THE TWO
(C). BULLET DIRECTION WAS FROM LEFT TO RIGHT.

7. CONCLUSION
This forensic ballistics case study explored the use of CT-based 3D
reconstruction to digitally visualize gunshot cavities in ballistic gelatine
blocks. A preliminary method was introduced for future refinement and
use by researchers and forensic professionals. The study's findings may
benefit forensic pathologists, trauma centers, and ballistic experts by
enhancing the documentation and evaluation of gunshot injuries. It also
offers potential value for judicial proceedings by providing clear, accurate
visualizations of gunshot-related findings. Additionally, the method may
have applications in wildlife forensics and serves as a foundation for
future studies on larger datasets.

9. THANK YOU