Non-destructive identification of wood from XVII Century panel painting using clinical X-ray computed tomography Hounsfield Units scale

X-ray Computed Tomography (CT) is a well-established non-destructive imaging technique mainly used to investigate structures and materials of complex objects that can be useful for conservation purposes. In this study, a novel methodology for cultural heritage materials identification directly on computed tomography (CT) images is shown. The approach consists of the adoption of the Hounsfield Units (HU) scale, generally used in medical radiology, which corresponds to the linear attenuation coefficient (µ) and is related to the density of the material expressed in Kg/m3. Clinical instrumentation and software were employed to analyse different types of wood material that constitute the support of a seventeenth-century panel painting from the collection of the National Academy of San Luca Gallery in Rome. These data were compared with reference samples elaborated with the same methodology and three-dimensional Volume Render Techniques (VRT) CT filters, calibrated on human body tissues, were selected, and classified as the most suitable for non-destructive heritage material identification in order to develop a protocol optimized for art radiology.