Investigation of a novel approach to forensic analysis using neutron imaging techniques

This proof-of-principle research focused on establishing the novel use of neutron radiography for forensic research and, more precisely, for the determination of post-mortem interval (PMI) by the measurement of changes in neutron attenuation in decaying canine skeletal muscle. This research answered two questions: (1) how to select the optimal tissues and how those tissues are best prepared for neutron radiography and (2) what is the effectiveness of using neutrons to measure changes in the decaying tissues as a function of time. Controlled (i.e. laboratory settings at the Oak Ridge National Laboratory) and uncontrolled (i.e. Anthropology Research Facility at the University of Tennessee, Knoxville) conditions were used to study the effects of different environmental conditions (mainly temperature and humidity) on the neutron transmission through the tissue samples. The primary hypothesis of this study is that by measuring the change in the hydrogen (H) content determined by neutron transmission, the state of canine skeletal muscle degradation can be predicted. Results demonstrated that the increase in neutron transmission that corresponded to a decrease in hydrogen content in the tissue was correlated with the time of decay of the tissue. Tissues depleted in hydrogen are brighter in the neutron transmission radiographs of skeletal muscles, lung, and bone, under controlled conditions. Over a period of 10 days, changes in neutron transmission through lung and muscle were found to be higher than bone by 8.3%, 7.0 %, and 2.0 %, respectively. In conclusion, neutron radiography can be used for detection of hydrogen changes in decaying tissues that are correlated with the post-mortem interval.