Detection of Foreign Bodies in Simulated Wounds Using the Acoustic Emission Method

Introduction: Shrapnel and ballistic injuries are common in modern warfare, with many foreign bodies (FBs) undetectable by conventional imaging methods like X-ray or MRI. There is a critical need for a reliable, portable, and radiation-free method to detect radiolucent FBs in soft tissues, particularly in resource-limited or battlefield conditions. Methods: We developed and tested a prototype device using the Acoustic Emission (AE) method, which detects transient elastic waves generated when a flexible probe contacts a foreign object. Simulated wound channels were created in bovine muscle tissue, embedding fragments of metal, plastic, glass, and stone. Signals were captured with a microphone, analyzed with spectral tools and Fourier decomposition, and evaluated using fuzzy logic algorithms. Multiple probe configurations and contact conditions were evaluated. Results: Fragments ≥2.5 mm were detected with >50% accuracy; metal fragments ≥5.0 mm reached 80% accuracy. The detection of plastic fragments was least reliable. Glass and stone fragments showed moderate accuracy that increased with size. Short probes (300 mm, 5.2 mm diameter) produced the most consistent and clear signals. Signal analysis revealed that frequency spectrum width, rather than amplitude, correlated best with fragment type and size. Signal-to-noise ratios improved with gain adjustments and optimized filters. Conclusion: The AE method shows promise as a diagnostic tool for identifying foreign bodies, including radiolucent fragments, in wound channels. The technique offers a low-cost, portable, and radiation-free alternative suitable for field and emergency use. Further development and clinical validation could improve early detection and management of shrapnel injuries in both military and civilian settings.