Micro X-ray computed tomography (μCT) for forensic investigation of wood

Wood is a common material and is widely used in daily life. Small wood fragments or wooden products are sometimes found at crime scenes as evidence. We investigated the usefulness of micro-computed tomography (μCT) for forensic wood examination. First, X-ray and image acquisition conditions were optimized, and the relation between the μCT image resolution and the observable anatomical features of wood was examined. The minimum resolution mainly depended on the μCT instrument specifications; thus, the relationship between the voxel size in μCT images and the size of anatomical features should be checked. Next, μCT technique was applied to the forensic wooden samples such as fragile charcoal, wooden household items, and building materials damaged by fire. μCT analysis is useful for the estimation of wood species, forensic discrimination for trace or fragile wooden evidence, identification of broken household items, and imaging the fire damage of building materials in the fire investigation. μCT is a non-destructive technique and could be used for many types of forensic wood investigation.