Abstract: Objective Using microbeam X-ray fluorescence（Micro-XRF） analyzer for determination of acid-resistant silicic particles in lung, and to explore its potential application in diagnosis of drowning. Methods Thirty two white rabbits were divided randomly into drowning group（n=12）, post-mortem immersion group （n=10） and control group （n=10）. Lungs and water sample were collected for determination of area concentration of acid-resistant silicic particles using Micro-XRF method. Results The area concentration of acid-resistant silicic particles for the drowning water sample was 4.4 mm2/mL. For the lungs of drowning group, the post-mortem immersion group and the control group, the determined average values were （25.30±10.95） mm2/g, （1.68±0.63） mm2/g and （1.65±0.85） mm2/g, respectively, with a statistically significant difference between the drowning group and the other two groups. Conclusion The area concentration of acid-resistant silicic particles in lungs may be used as an indicator of drowning. The method is highly sensitive and rapid. It provides a potential application in drowning diagnosis.

Key words: forensic pathology, drowning, lung, microbeam X-ray fluorescence, silica parti, rabbits